VLT® Frequency Converters Safe Torque O
Operating Guide.
Approvals.
®
EtherNet/IP MCA 121 Installation
WARNING
Indicates a potentially hazardous situation that could
result in death or serious injury.
CAUTION
Indicates a potentially hazardous situation that could
result in minor or moderate injury. It may also be used
to alert against unsafe practices.
NOTICE!
Indicates important information, including situations that
may result in damage to equipment or property.
The following conventions are used in this manual:
Numbered lists indicate procedures.
•
Bullet lists indicate other information and
•
description of illustrations.
Italicized text indicates:
•
-Cross-reference.
-Link.
-Footnote.
-Parameter name.
-Parameter group name.
-Parameter option.
All dimensions in drawings are in mm (inch).
•
Document and Software Version
1.2
This manual is regularly reviewed and updated. All
suggestions for improvement are welcome. Table 1.1 shows
the document version and the corresponding software
version.
EditionRemarksSoftware version
MG04H3xx EMC-correct Installation has been
updated.
Table 1.1 Document and Software Version
Denitions
1.3
1.3.1 Frequency Converter
I
VLT,MAX
Maximum output current.
I
VLT,N
Rated output current supplied by the frequency converter.
Start and stop the connected motor with LCP and digital
inputs.
Functions are divided into 2 groups.
Functions in group 1 have higher priority than functions in
group 2.
Group 1Reset, coast stop, reset and coast stop, quick stop,
DC brake, stop, the [OFF] key.
Group 2Start, pulse start, reversing, start reversing, jog,
freeze output.
Table 1.2 Function Groups
1.3.3 Motor
U
M,N
Rated motor voltage (nameplate data).
Break-away torque
11
Motor running
Torque generated on output shaft and speed from 0 RPM
to maximum speed on motor.
f
JOG
Motor frequency when the jog function is activated (via
digital terminals).
f
M
Motor frequency.
f
MAX
Maximum motor frequency.
f
MIN
Minimum motor frequency.
f
M,N
Rated motor frequency (nameplate data).
I
M
Motor current (actual).
I
M,N
Rated motor current (nameplate data).
n
M,N
Nominal motor speed (nameplate data).
n
s
Synchronous motor speed.
2 × par . 1 − 23 × 60s
ns=
n
slip
par . 1 − 39
Motor slip.
P
M,N
Rated motor power (nameplate data in kW or hp).
T
M,N
Rated torque (motor).
U
M
Instant motor voltage.
Figure 1.1 Break-away Torque
η
VLT
The eciency of the frequency converter is dened as the
ratio between the power output and the power input.
Start-disable command
A stop command belonging to Group 1 control commands
- see Table 1.2.
Stop command
A stop command belonging to Group 1 control commands
- see Table 1.2.
1.3.4 References
Analog reference
A signal transmitted to the analog inputs 53 or 54 (voltage
or current).
Binary reference
A signal transmitted to the serial communication port.
Preset reference
A dened preset reference to be set from -100% to +100%
of the reference range. Selection of 8 preset references via
the digital terminals.
Pulse reference
A pulse frequency signal transmitted to the digital inputs
(terminal 29 or 33).
Ref
MAX
Determines the relationship between the reference input at
100% full scale value (typically 10 V, 20 mA) and the
resulting reference. The maximum reference value is set in
parameter 3-03 Maximum Reference.
Determines the relationship between the reference input at
0% value (typically 0 V, 0 mA, 4 mA) and the resulting
reference. The minimum reference value is set in
parameter 3-02 Minimum Reference.
1.3.5 Miscellaneous
Analog inputs
The analog inputs are used for controlling various
functions of the frequency converter.
There are 2 types of analog inputs:
Current input, 0–20 mA, and 4–20 mA
Voltage input, -10 V DC to +10 V DC.
Analog outputs
The analog outputs can supply a signal of 0–20 mA, 4–
20 mA.
Automatic motor adaptation, AMA
AMA algorithm determines the electrical parameters for
the connected motor at standstill.
Brake resistor
The brake resistor is a module capable of absorbing the
brake power generated in regenerative braking. This
regenerative brake power increases the DC-link voltage
and a brake chopper ensures that the power is transmitted
to the brake resistor.
CT characteristics
Constant torque characteristics used for all applications
such as conveyor belts, displacement pumps, and cranes.
Digital inputs
The digital inputs can be used for controlling various
functions of the frequency converter.
Digital outputs
The frequency converter features 2 solid-state outputs that
can supply a 24 V DC (maximum 40 mA) signal.
DSP
Digital signal processor.
ETR
Electronic thermal relay is a thermal load calculation based
on present load and time. Its purpose is to estimate the
motor temperature.
Hiperface
Hiperface® is a registered trademark by Stegmann.
Initializing
If initializing is carried out (parameter 14-22 Operation
Mode), the frequency converter returns to the default
setting.
®
Intermittent duty cycle
An intermittent duty rating refers to a sequence of duty
cycles. Each cycle consists of an on-load and an o-load
period. The operation can be either periodic duty or nonperiodic duty.
LCP
The local control panel makes up a complete interface for
control and programming of the frequency converter. The
control panel is detachable and can be installed up to 3 m
(10 ft) from the frequency converter, that is, in a front
panel with the installation kit option.
lsb
Least signicant bit.
msb
Most signicant bit.
MCM
Short for mille circular mil, an American measuring unit for
cable cross-section. 1 MCM=0.5067 mm2.
Online/oine parameters
Changes to online parameters are activated immediately
after the data value is changed. Press [OK] to activate
changes to o-line parameters.
Process PID
The PID control maintains the required speed, pressure,
temperature, and so on, by adjusting the output frequency
to match the varying load.
PCD
Process control data.
Power cycle
Switch o the mains until display (LCP) is dark, then turn
power on again.
Pulse input/incremental encoder
An external, digital pulse transmitter used for feeding back
information on motor speed. The encoder is used in
applications where great accuracy in speed control is
required.
RCD
Residual current device.
Set-up
Save parameter settings in 4 set-ups. Change between the
4 parameter set-ups and edit 1 set-up, while another setup is active.
The frequency converter compensates for the motor slip by
giving the frequency a supplement that follows the
measured motor load keeping the motor speed almost
constant.
The SLC (smart logic control) is a sequence of user-dened
actions executed when the associated user-dened events
are evaluated as true by the SLC. (See chapter 4.9.1 SmartLogic Controller).
STW
Status word.
FC standard bus
Includes RS485 bus with FC protocol or MC protocol. See
parameter 8-30 Protocol.
THD
Total harmonic distortion states the total contribution of
harmonic.
Thermistor
A temperature-dependent resistor placed on the frequency
converter or the motor.
Trip
A state entered in fault situations, for example if the
frequency converter is subject to an overtemperature or
when the frequency converter is protecting the motor,
process, or mechanism. The frequency converter prevents a
restart until the cause of the fault has disappeared. To
cancel the trip state, restart the frequency converter. Do
not use the trip state for personal safety.
Trip lock
The frequency converter enters this state in fault situations
to protect itself. The frequency converter requires physical
intervention, for example when there is a short circuit on
the output. A trip lock can only be canceled by disconnecting mains, removing the cause of the fault, and
reconnecting the frequency converter. Restart is prevented
until the trip state is canceled by activating reset or,
sometimes, by being programmed to reset automatically.
Do not use the trip lock state for personal safety.
VT characteristics
Variable torque characteristics used for pumps and fans.
+
VVC
If compared with standard voltage/frequency ratio control,
voltage vector control (VVC+) improves the dynamics and
the stability, both when the speed reference is changed
and in relation to the load torque.
The power factor indicates to which extent the frequency
converter imposes a load on the mains supply.
The lower the power factor, the higher the I
RMS
for the
same kW performance.
I
RMS
=
I
+ I
1
5
+ I
2
+ .. + I
7
2
n
2
2
In addition, a high-power factor indicates that the dierent
harmonic currents are low.
The DC coils in the frequency converters produce a highpower factor, which minimizes the imposed load on the
mains supply.
Target position
The nal target position specied by positioning
commands. The prole generator uses this position to
calculate the speed prole.
Commanded position
The actual position reference calculated by the prole
generator. The frequency converter uses the commanded
position as setpoint for position PI.
Actual position
The actual position from an encoder, or a value that the
motor control calculates in open loop. The frequency
converter uses the actual position as feedback for position
PI.
Position error
Position error is the dierence between the actual position
and the commanded position. The position error is the
input for the position PI controller.
The voltage of the frequency converter is dangerous
whenever connected to mains. Correct planning of the
installation of the motor, frequency converter, and
eldbus are necessary. Follow the instructions in this
manual, and the national and local rules and safety
regulations. Failure to follow design recommendations
could result in death, serious personal injury, or damage
to the equipment once in operation.
WARNING
HIGH VOLTAGE
Touching the electrical parts may be fatal - even after
the equipment has been disconnected from mains.
In planning, ensure that other voltage inputs can be
disconnected, such as external 24 V DC, load sharing
(linkage of DC intermediate circuit), and the motor
connection for kinetic back-up.
Systems where frequency converters are installed must, if
necessary, be equipped with additional monitoring and
protective devices according to the valid safety
regulations, for example law on mechanical tools,
regulations for the prevention of accidents, and so on.
Modications on the frequency converters by means of
the operating software are allowed.
Failure to follow design recommendations, could result in
death or serious injury once the equipment is in
operation.
NOTICE!
Hazardous situations have to be identied by the
machine builder/integrator who is responsible for taking
necessary preventive means into consideration.
Additional monitoring and protective devices may be
included, always according to valid national safety
regulations, for example, law on mechanical tools,
regulations for the prevention of accidents.
NOTICE!
Crane, lifts, and hoists:
The controlling of external brakes must always be
designed with a redundant system. The frequency
converter can in no circumstances be the primary safety
circuit. Comply with relevant standards, for example.
Hoists and cranes: IEC 60204-32
Lifts: EN 81
Protection mode
Once a hardware limit on motor current or DC-link voltage
is exceeded, the frequency converter enters protection
mode. Protection mode means a change of the PWM
modulation strategy and a low switching frequency to
minimize losses. This continues 10 s after the last fault and
increases the reliability and the robustness of the
frequency converter while re-establishing full control of the
motor.
In hoist applications, protection mode is not usable
because the frequency converter is usually unable to leave
this mode again and therefore it extends the time before
activating the brake – which is not recommended.
The protection mode can be disabled by setting
parameter 14-26 Trip Delay at Inverter Fault to 0 which
means that the frequency converter trips immediately if 1
of the hardware limits is exceeded.
NOTICE!
Disable protection mode in hoisting applications
(parameter 14-26 Trip Delay at Inverter Fault=0).
WARNING
DISCHARGE TIME
The frequency converter contains DC-link capacitors,
which can remain charged even when the frequency
converter is not powered. High voltage can be present
even when the warning LED indicator lights are o.
Failure to wait the specied time after power has been
removed before performing service or repair work can
result in death or serious injury.
Stop the motor.
•
Disconnect AC mains and remote DC-link power
•
supplies, including battery back-ups, UPS, and
DC-link connections to other frequency
converters.
Disconnect or lock PM motor.
•
Wait for the capacitors to discharge fully. The
•
minimum waiting time is specied in Table 1.3
and is also visible on the product label on top
of the frequency converter.
Before performing any service or repair work,
•
use an appropriate voltage measuring device to
make sure that the capacitors are fully
discharged.
CE labeling is a positive feature when used for its original
purpose, that is, to facilitate trade within the EU and EFTA.
However, CE labeling may cover many
cations. Check what a given CE label specically covers.
The specications can vary greatly. A CE label may
therefore give the installer a false sense of security when
using a frequency converter as a component in a system
or an appliance.
Danfoss CE labels the frequency converters in accordance
with the Low Voltage Directive. This means that if the
frequency converter is installed correctly, compliance with
the Low Voltage Directive is achieved. Danfoss issues a
declaration of conformity that conrms CE labeling in
accordance with the Low Voltage Directive.
The CE label also applies to the EMC directive, if the
instructions for EMC-correct installation and
followed. On this basis, a declaration of conformity in
accordance with the EMC directive is issued.
dierent speci-
ltering are
What is CE conformity and labeling?
The purpose of CE labeling is to avoid technical trade
obstacles within EFTA and the EU. The EU has introduced
the CE label as a simple way of showing whether a
product complies with the relevant EU directives. The CE
label says nothing about the specications or quality of
the product. Frequency converters are regulated by 2 EU
directives:
The Low Voltage Directive (2014/35/EU)
Frequency converters must be CE-labeled in accordance
with the Low Voltage Directive of January 1, 2014. The Low
Voltage Directive applies to all electrical equipment in the
50–1000 V AC and the 75–1500 V DC voltage ranges.
The aim of the directive is to ensure personal safety and
avoid property damage when operating electrical
equipment that is installed, maintained, and used as
intended.
The EMC Directive (2014/30/EU)
The purpose of the EMC (electromagnetic compatibility)
Directive is to reduce electromagnetic interference and
enhance immunity of electrical equipment and installations. The basic protection requirement of the EMC
Directive is that devices that generate electromagnetic
interference (EMI), or whose operation could be aected
by EMI, must be designed to limit the generation of
electromagnetic interference. The devices must have a
suitable degree of immunity to EMI when properly
installed, maintained, and used as intended.
Electrical equipment devices used alone or as part of a
system must bear the CE mark. Systems do not require the
CE mark, but must comply with the basic protection
requirements of the EMC Directive.
The frequency converter is most often used by professionals of the trade as a complex component forming part
of a larger appliance, system, or installation.
The design guide oers detailed instructions for installation
to ensure EMC-correct installation.
1.5.1 Conformity
The Machinery Directive (2006/42/EC)
Frequency converters do not fall under the machinery
directive. However, if a frequency converter is supplied for
use in a machine, Danfoss provides information on safety
aspects relating to the frequency converter.
The EU EMC Directive 2014/30/EU outline 3 typical
situations of using a frequency converter. See below for
EMC coverage and CE labeling.
The frequency converter is sold directly to the
•
end user. The frequency converter is for example
sold to a do-it-yourself market. The end user is a
layman, installing the frequency converter for use
with a hobby machine, a kitchen appliance, and
so on. For such applications, the frequency
converter must be CE labeled in accordance with
the EMC directive.
The frequency converter is sold for installation in
•
a plant. The plant is built up by professionals of
the trade. It could be a production plant or a
heating/ventilation plant designed and installed
by professionals of the trade. The frequency
converter and the nished plant do not have to
be CE labeled under the EMC directive. However,
the unit must comply with the basic EMC
requirements of the directive. This is ensured by
using components, appliances, and systems that
are CE labeled under the EMC directive.
The frequency converter is sold as part of a
•
complete system. The system is marketed as
complete, for example an air-conditioning system.
The complete system must be CE labeled in
accordance with the EMC directive. The
manufacturer can ensure CE labeling under the
EMC directive either by using CE labeled
components or by testing the EMC of the system.
If only CE labeled components are used, it is
unnecessary to test the entire system.
Approvals
1.7
Table 1.4 FCD 302 Approvals
The frequency converter complies with UL 508C thermal
memory retention requirements. For more information,
refer to chapter 3.4.3.2 Motor Thermal Protection.
1.8 Disposal
Equipment containing electrical
components may not be disposed of
together with domestic waste.
It must be separately collected with
electrical and electronic waste according
to local and currently valid legislation.
Table 1.5 Disposal Instruction
Compliance with EMC Directive
1.6
2004/1087EC
The frequency converter is mostly used by professionals of
the trade as a complex component forming part of a larger
appliance, system, or installation.
NOTICE!
The responsibility for the nal EMC properties of the
appliance, system, or installation rests with the installer.
As an aid to the installer, Danfoss has prepared EMC installation guidelines for the power drive system. The standards
and test levels stated for power drive systems are complied
with, if the EMC-correct instructions for installation are
followed, see chapter 2.9.4 EMC.
relevant creepage/clearance distances. These requirements
are described in the EN 61800-5-1 standard.
The components that make up the electrical isolation, as
described in Figure 2.3, also comply with the requirements
for higher isolation and the relevant test as described in
EN 61800-5-1.
The PELV galvanic isolation can be shown in 6 locations
(see Figure 2.3).
To maintain PELV, all connections made to the control
terminals must be PELV, for example, thermistor must be
reinforced/double insulated.
1Power supply (SMPS) including signal isolation of UDC,
indicating the voltage of intermediate DC Link circuit.
2Gate drive that runs the IGBTs (trigger transformers/opto-
Figure 2.2 Large Unit
2.1 Galvanic Isolation (PELV)
2.1.1 PELV - Protective Extra Low Voltage
PELV oers protection by way of extra low voltage.
Protection against electric shock is ensured when the
electrical supply is of the PELV type and the installation is
couplers).
3Current transducers.
4Opto-coupler, brake module.
5Internal inrush, RFI, and temperature measurement circuits.
6Custom relays.
7Mechanical brake.
8Functional galvanic isolation for the 24 V back-up option
and for the RS485 standard bus interface.
9Functional galvanic isolation for the 24 V back-up option
and for the RS485 standard bus interface.
made as described in local/national regulations on PELV
supplies.
Figure 2.3 Galvanic Isolation
All control terminals and relay terminals 01–03/04–06
comply with PELV (protective extra low voltage), except for
grounded delta leg above 400 V.
Galvanic (ensured) isolation is obtained by fullling
NOTICE!
Installation at high altitude:
380–500 V: At altitudes above 2000 m (6561 ft), contact
Danfoss regarding PELV.
requirements for higher isolation and by providing the
Follow national and local codes regarding protective
grounding of equipment with a leakage current >3.5 mA.
Frequency converter technology implies high frequency
switching at high power. This generates a leakage current
in the ground connection. A fault current in the frequency
converter at the output power terminals might contain a
DC component which can charge the lter capacitors and
cause a transient ground current.
The leakage current also depends on the line distortion.
NOTICE!
When a lter is used, turn oparameter 14-50 RFI Filter
when charging the lter, to avoid that a high leakage
current makes the RCD switch.
EN/IEC61800-5-1 (power drive system product standard)
requires special care if the leakage current exceeds 3.5 mA.
Grounding must be reinforced in 1 of the following ways:
Figure 2.4 Inuence of Cut-o Frequency of the RCD
Ground wire (terminal 95) of at least 10 mm
•
(7 AWG). This requires a PE adapter (available as
an option).
Two separate ground wires both complying with
•
the dimensioning rules.
See EN/IEC61800-5-1 and EN 50178 for further information.
Using RCDs
Where residual current devices (RCDs), also known as
ground leakage circuit breakers (CLCBs), are used, comply
with the following:
Use RCDs of type B, which are capable of
•
detecting AC and DC currents.
Use RCDs with an inrush delay to prevent faults
•
due to transient ground currents.
Dimension RCDs according to the system
•
ration and environmental considerations.
2
congu-
See also RCD Application Note.
Control
2.2
A frequency converter recties AC voltage from mains into
DC voltage. This DC voltage is converted into an AC
current with a variable amplitude and frequency.
The motor is supplied with variable voltage, current, and
frequency, which enables innitely variable speed control
of 3-phased, standard AC motors and permanent magnet
synchronous motors.
The VLT® Decentral Drive FCD 302 frequency converter is
designed for installations of multiple smaller frequency
converters, especially on conveyor applications, for
example, in the food and beverage industries and materials
handling. In installations where multiple motors are spread
around a facility such as bottling plants, food preparation,
packaging plants, and airport baggage handling installations, there may be dozens, perhaps hundreds, of
frequency converters, working together but spread over a
large physical area. In these cases, cabling costs alone
outweigh the cost of the individual frequency converters
and it makes sense to get the control closer to the motors.
The frequency converter can control either the speed or
the torque on the motor shaft.
speed feedback to an input. A properly optimized
speed closed-loop control is more accurate than a
speed open-loop control.
Torque control
The torque control function is used in applications where
the torque on motor output shaft controls the application
as tension control.
Closed loop in ux mode with encoder feedback
•
comprises motor control based on feedback
signals from the system. It improves performance
in all 4 quadrants and at all motor speeds.
Open loop in VVC+ mode. The function is used in
•
mechanical robust applications, but the accuracy
is limited. Open-loop torque function works only
in 1 speed direction. The torque is calculated on
basis of current measurement internal in the
frequency converter. See application example
chapter 2.3.1 Control Structure in VVC+ Advanced
Vector Control.
Speed/torque reference
The reference to these controls can either be a single
reference or be the sum of various references including
relatively scaled references. The handling of references is
explained in detail in chapter 2.6 Handling of Reference.
22
2.2.1 Control Principle
The frequency converter is compatible with various motor control principles such as U/f special motor mode, VVC+, or ux
vector motor control.
In addition, the frequency converter is operable with permanent magnet synchronous motors (brushless servo motors) and
normal squirrel lift cabin asynchronous motors.
The short circuit behavior depends on the 3 current transducers in the motor phases and the desaturation protection with
feedback from the brake.
The frequency converter features an integral current limit control which is activated when the motor current, and thus the
torque, is higher than the torque limits set in parameter 4-16 Torque Limit Motor Mode, parameter 4-17 Torque Limit GeneratorMode, and parameter 4-18 Current Limit.
When the frequency converter is at the current limit during motor operation or regenerative operation, it reduces torque to
below the preset torque limits as quickly as possible without losing control of the motor.
2.3 Control Structures
2.3.1
Control Structure in VVC+ Advanced Vector Control
Figure 2.6 Control Structure in VVC+ Open-loop and Closed-loop Congurations
In the conguration shown in Figure 2.6, parameter 1-01 Motor Control Principle is set to [1] VVC+ and parameter 1-00 Congu-
ration Mode is set to [0] Speed open loop. The resulting reference from the reference handling system is received and fed
through the ramp limitation and speed limitation before being sent to the motor control. The output of the motor control is
then limited by the maximum frequency limit.
If parameter 1-00
and speed limitation into a speed PID control. The speed PID control parameters are in the parameter group 7-0* Speed PIDCtrl. The resulting reference from the speed PID control is sent to the motor control limited by the frequency limit.
Select [3] Process in parameter 1-00 Conguration Mode to use the process PID control for closed-loop control of, for example,
speed or pressure in the controlled application. The process PID parameters are in parameter group 7-2* Process Ctrl. Feedb
and parameter group 7-3* Process PID Ctrl.
Conguration Mode is set to [1] Speed closed loop, the resulting reference passes from the ramp limitation
+
_
+
_
130BA053.11
Ref.
Cong. mode
P 1-00
P 7-20 Process feedback
1 source
P 7-22 Process feedback
2 source
Process
PID
P 4-11 Motor speed
low limit [RPM]
P 4-12 Motor speed
low limit [Hz]
P 4-14 Motor speed
high limit [Hz]
P 4-13 Motor speed
high limit [RPM]
Low
High
Ramp
P 3-**
+f max.
P 4-19
Max. output
freq.
Motor
controller
-f max.
Speed
PID
P 7-0*
Product Overview and Functi...Design Guide
2.3.2 Control Structure in Flux Sensorless
Control structure in ux sensorless open-loop and closed-loop congurations.
22
Figure 2.7 Control Structure in Flux Sensorless
In the conguration shown, parameter 1-01 Motor Control Principle is set to [2] Flux Sensorless and parameter 1-00 Congu-
ration Mode is set to [0] Speed open loop. The resulting reference from the reference handling system is fed through the
ramp and speed limitations as determined by the parameter settings indicated.
An estimated speed feedback is generated to the speed PID to control the output frequency.
The speed PID must be set with its P, I, and D parameters (parameter group 7-0* Speed PID Ctrl.).
Select [3] Process in parameter 1-00 Conguration Mode to use the process PID control for closed-loop control of speed or
pressure in the controlled application. The process PID parameters are in parameter group 7-2* Process Ctrl. Feedb. and
parameter group7-3* Process PID Ctrl.
P 7-20 Process feedback
1 source
P 7-22 Process feedback
2 source
P 4-11 Motor speed
low limit (RPM)
P 4-12 Motor speed
low limit (Hz)
P 4-13 Motor speed
high limit (RPM)
P 4-14 Motor speed
high limit (Hz)
High
Low
Ref.
Process
PID
Speed
PID
Ramp
P 7-00
PID source
Motor
controller
-f max.
+f max.
P 4-19
Max. output
freq.
P 1-00
Cong. mode
P 1-00
Cong. mode
Torque
Product Overview and Functi...
VLT® Decentral Drive FCD 302
2.3.3 Control Structure in Flux with Motor Feedback
22
Figure 2.8 Control Structure in Flux with Motor Feedback
In the conguration shown, parameter 1-01 Motor Control Principle is set to [3] Flux w motor feedb and parameter 1-00 Cong-
uration Mode is set to [1] Speed closed loop.
The motor control in this conguration relies on a feedback signal from an encoder mounted directly on the motor (set in
parameter 1-02 Flux Motor Feedback Source).
Select [1] Speed closed loop in parameter 1-00 Conguration Mode to use the resulting reference as an input for the speed
PID control. The speed PID control parameters are located in parameter group 7-0* Speed PID Ctrl.
Select [2] Torque in parameter 1-00 Conguration Mode to use the resulting reference directly as a torque reference. Torque
control can only be selected in the [3] Flux with motor feedback (parameter 1-01 Motor Control Principle) conguration. When
this mode has been selected, the reference uses the Nm unit. It requires no torque feedback, since the actual torque is
calculated based on the current measurement of the frequency converter.
Select [3] Process in parameter 1-00
Conguration Mode to use the process PID control for closed-loop control of a process
variable (for example, speed) in the controlled application.
2.3.4 Local [Hand On] and Remote [Auto
On] Control
The frequency converter can be operated manually via the
local control panel (LCP) or remotely via analog and digital
inputs and eldbus. If allowed in parameter 0-40 [Hand on]
Key on LCP, parameter 0-41 [O] Key on LCP,
parameter 0-42 [Auto on] Key on LCP, and
parameter 0-43 [Reset] Key on LCP, it is possible to start and
stop the frequency converter via the LCP using the [Hand
On] and [O] keys. Alarms can be reset via the [Reset] key.
After pressing the [Hand On] key, the frequency converter
goes into hand-on mode and follows (as default) the local
reference that can be set using the navigation keys on the
LCP.
After pressing the [Auto On] key, the frequency converter
goes into auto-on mode and follows (as default) the
remote reference. In this mode, it is possible to control the
frequency converter via the digital inputs and various serial
interfaces (RS485, USB, or an optional
about starting, stopping, changing ramps, parameter setups, and so on, in parameter group 5-1* Digital Inputs or
parameter group 8-5* Digital/Bus.
eldbus). See more
Active reference and conguration mode
The active reference can be either the local reference or
the remote reference.
In parameter 3-13 Reference Site, the local reference can be
permanently selected by selecting [2] Local.
For permanent setting of the remote reference, select [1]Remote. By selecting [0] Linked to Hand/Auto (default), the
reference site links to the active mode (hand-on mode or
auto-on Mode).
Parameter 5-40 Function Relay [32] Mechanical
Brake Control
of application control principle (that is, speed, torque, or
process control) is used when the remote reference is
active. Parameter 1-05 Local Mode Conguration determines
the type of application control principle that is used when
the local reference is active. One of them is always active,
but both cannot be active at the same time.
2.3.5 Programming of Torque Limit and
Stop
In applications with an external electro-mechanical brake,
such as hoisting applications, it is possible to stop the
frequency converter via a standard stop command and
simultaneously activate the external electro-mechanical
brake.
The example given below, illustrates the programming of
the frequency converter connections.
The external brake can be connected to relay 1 or 2.
Program parameter 5-01 Terminal 27 Mode to [2] Coast,
inverse or [3] Coast and Reset, inverse, and program
parameter 5-02 Terminal 29 Mode to [1] Output and [27]
Torque limit & stop.
ItemDescription
1External 24 V DC
2Mechanical brake connection
3Relay 1
Figure 2.12 Mechanical Brake Control
Description
If a stop command is active via terminal 18, and the
frequency converter is not at the torque limit, the motor
ramps down to 0 Hz.
If the frequency converter is at the torque limit and a stop
command is activated, parameter 5-31 Terminal 29 digitalOutput (programmed to [27] torque limit and stop) is
activated. The signal to terminal 27 changes from logic 1
to logic 0, and the motor starts to coast. The coast ensures
that the hoist stops even if the frequency converter itself
cannot handle the required torque (that is, due to
excessive overload).
Parameter 5-12 Terminal 27 Digital Input [2] Coast
Stop, inverse
Terminal 29 output
Product Overview and Functi...Design Guide
2.4 PID Control
2.4.1 Speed PID Control
22
Parameter 1-00 Congu-
ration Mode
[0] Speed open loop
[1] Speed closed loop–Active–Active
[2] Torque–––
[3] Process–
Table 2.2 Control Congurations where the Speed Control is Active
1) “Not active” means that the specic mode is available, but the speed control is not active in that mode.
Parameter 1-01 Motor Control Principle
U/f
Not active
1)
+
VVC
Not active
Not active
Flux sensorlessFlux w/ encoder feedback
1)
1)
Active–
Not active
ActiveActive
1)
NOTICE!
The speed PID control works under the default parameter setting, but tuning the parameters is highly recommended to
optimize the motor control performance. The 2 ux motor control principles are particularly dependent on proper
tuning to yield their full potential.
2.4.2 Parameters Relevant for Speed Control
ParameterDescription of function
Parameter 7-00 Speed PID Feedback SourceSelect from which input the speed PID should get its feedback.
Parameter 30-83 Speed PID Proportional GainThe higher the value - the quicker the control. However, too high value may lead to
oscillations.
Parameter 7-03 Speed PID Integral TimeEliminates steady state speed error. Lower value means quick reaction. However, too low
value may lead to oscillations.
Parameter 7-04 Speed PID Dierentiation Time Provides a gain proportional to the rate of change of the feedback. A setting of 0 disables
the dierentiator.
Parameter 7-05 Speed PID Di. Gain LimitIf there are quick changes in reference or feedback in a given application, which means
that the error changes swiftly, the dierentiator may soon become too dominant. This is
because it reacts to changes in the error. The quicker the error changes, the stronger the
dierentiator gain is. The dierentiator gain can thus be limited to allow setting of the
reasonable dierentiation time for slow changes and a suitably quick gain for quick
changes.
Parameter 7-06 Speed PID Lowpass Filter Time A low-pass lter that dampens oscillations on the feedback signal and improves steady
state performance. However, too large lter time deteriorates the dynamic performance of
the speed PID control.
Practical settings of parameter 7-06 Speed PID Lowpass Filter Time taken from the number of
pulses per revolution from encoder (PPR):
Encoder PPRParameter 7-06 Speed PID Lowpass Filter Time
In this case, the speed PID control is used to maintain a constant motor speed regardless of the changing load on the
motor. The required motor speed is set via a potentiometer connected to terminal 53. The speed range is 0–1500 RPM
corresponding to 0–10 V over the potentiometer. Starting and stopping is controlled by a switch connected to terminal 18.
The speed PID monitors the actual RPM of the motor by using a 24 V (HTL) incremental encoder as feedback. The feedback
sensor is an encoder (1024 pulses per revolution) connected to terminals 32 and 33.
Figure 2.13 Example - Speed Control Connections
The following must be programmed in the order shown (see explanation of settings in the
301/FC 302 Programming Guide)
In the list, it is assumed that all other parameters and switches remain at their default setting.
FunctionParameterSetting
1) Make sure that the motor runs properly. Do the following:
Set the motor parameters using nameplate data.Parameter group 1-2*
Motor Data
Perform an automatic motor adaptation.Parameter 1-29 Auto
matic Motor
Adaptation (AMA)
2) Check that the motor is running and that the encoder is attached properly. Do the following:
Press the [Hand On] LCP key. Check that the motor is
–Set a positive reference.
running and note in which direction it is turning
(referred to as the positive direction).
Go to parameter 16-20 Motor Angle. Turn the motor
slowly in the positive direction. It must be turned so
slowly (only a few RPM) that it can be determined if the
value in parameter 16-20 Motor Angle is increasing or
The following tuning guidelines are relevant when using 1
of the ux motor control principles in applications where
the load is mainly inertial (with a low amount of friction).
The value of parameter 30-83 Speed PID Proportional Gain
depends on the combined inertia of the motor and load,
and the selected bandwidth can be calculated using the
following formula:
Par . 7 − 02 =
Totalinertia k gm2xpar . 1 − 25
Par . 1 − 20x 9550
xBandwidth
NOTICE!
Parameter 1-20 Motor Power [kW] is the motor power in
[kW] (that is, enter 4 kW instead of 4000 W in the
formula).
A practical value for the bandwidth is 20 rad/s. Check the
result of the Parameter 30-83 Speed PID Proportional Gain
calculation against the following formula (not required
when using high-resolution feedback such as a SinCos
feedback):
rad/ s
other factors in the application might limit the
parameter 30-83 Speed PID Proportional Gain to a lower
value.
To minimize the overshoot, parameter 7-03 Speed PIDIntegral Time could be set to approximately 2.5 s (varies
with the application).
Parameter 7-04 Speed PID
to 0 until everything else is tuned. If necessary, nish the
tuning by experimenting with small increments of this
setting.
Dierentiation Time should be set
2.4.4 Process PID Control
The process PID Control can be used to control application
parameters that can be measured by a sensor (that is,
pressure, temperature, ow) and be aected by the
connected motor through a pump, fan, or otherwise.
Table 2.5 shows the control congurations where the
process control is possible. When a ux vector motor
control principle is used, take care also to tune the speed
control PID parameters. To see where the speed control is
active, refer to chapter 2.3 Control Structures.
Par . 7 − 02
0 . 01x4xEncoderResolutionxPar . 7 − 06
xMaxtorqueripple %
A good start value for parameter 7-06 Speed PID Lowpass
Filter Time is 5 ms (lower encoder resolution calls for a
higher lter value). Typically, a maximum torque ripple of
3% is acceptable. For incremental encoders, the encoder
resolution is found in either parameter 5-70 Term 32/33Pulses per Revolution (24 V HTL on standard frequency
converter) or parameter 17-11 Resolution (PPR) (5 V TTL on
VLT® Encoder Input MCB 102 option).
Generally, the practical maximum limit of
parameter 30-83 Speed PID Proportional Gain is determined
by the encoder resolution and the feedback lter time. But
MAX
=
2xπ
Parameter 1-00
Conguration
Mode
[3] Process–ProcessProcess
Table 2.5 Process PID Control Settings
Parameter 1-01 Motor Control Principle
U/f
VVC
+
Flux
sensorles
s
& speed
Flux with
encoder
feedback
Process &
speed
NOTICE!
The process PID control works under the default
parameter setting, but tuning the parameters is highly
recommended to optimize the application control
performance. The 2 ux motor control principles are
specially dependent on proper speed control PID tuning
(before tuning the process control PID) to yield their full
potential.
Figure 2.15 is an example of a process PID control used in a
ventilation system.
ItemDescription
1Cold air
2Heat generating process
3Temperature transmitter
4Temperature
5Fan speed
6Heat
22
Figure 2.16 Two-wire Transmitter
Figure 2.15 Process PID Control in Ventilation System
1.Start/stop via a switch connected to terminal 18.
In a ventilation system, the temperature is to be settable
from -5 to +35 °C (23–95 °F) with a potentiometer of 0–
10 V. The task of the process control is to maintain
temperature at a constant preset level.
2.Temperature reference via potentiometer (-5 to
35 °C (23–95 °F), 0–10 V DC) connected to
terminal 53.
3.Temperature feedback via transmitter (-10 to
40 °C (14–104 °F), 4–20 mA) connected to
The control is of the inverse type, which means that when
the temperature increases, the ventilation speed is
terminal 54. Switch S202 set to ON (current
input).
increased as well, to generate more air. When the
temperature drops, the speed is reduced. The transmitter
used is a temperature sensor with a working range of -10
to +40 °C (14–104 °F), 4–20 mA. Minimum/maximum
speed 300/1500 RPM.
The basic settings have now been made. All that needs to
be done is to optimize the proportional gain, the
integration time, and the dierentiation time
(parameter 7-33 Process PID Proportional Gain,
parameter 7-34 Process PID Integral Time,
parameter 7-35 Process PID Dierentiation Time). In most
processes, this can be done by following these guidelines:
1.Start the motor.
2.Set parameter 7-33 Process PID Proportional Gain
to 0.3 and increase it until the feedback signal
again begins to vary continuously. Then reduce
the value until the feedback signal has stabilized.
Now lower the proportional gain by 40–60%.
3.Set parameter 7-34 Process PID Integral Time to
20 s and reduce the value until the feedback
signal again begins to vary continuously. Increase
the integration time until the feedback signal
stabilizes, followed by an increase of 15–50%.
4.Only use parameter 7-35 Process PID
Time for very fast-acting systems only (dieren-
tiation time). The typical value is 4 times the set
integration time. The dierentiator should only be
used when the setting of the proportional gain
and the integration time has been fully
optimized. Make sure that oscillations on the
feedback signal are suciently dampened by the
lowpass lter on the feedback signal.
Dierentiation
NOTICE!
If necessary, start/stop can be activated several times to
provoke a variation of the feedback signal.
To tune the PID controls of the frequency converter,
Danfoss recommends the Ziegler Nichols tuning method.
NOTICE!
Do not use the Ziegler Nichols Tuning method in
applications that could be damaged by the oscillations
created by marginally stable control settings.
The criteria for adjusting the parameters are based on
evaluating the system at the limit of stability rather than
on taking a step response. Increase the proportional gain
until observing continuous oscillations (as measured on
the feedback), that is, until the system becomes marginally
stable. The corresponding gain (Ku) is called the ultimate
gain and is the gain, at which the oscillation is obtained.
The period of the oscillation (Pu) (called the ultimate
period) is determined as shown in Figure 2.17 and should
be measured when the amplitude of oscillation is small.
1.Select only proportional control, meaning that
the integral time is set to the maximum value,
while the dierentiation time is set to 0.
2.Increase the value of the proportional gain until
the point of instability is reached (sustained
oscillations) and the critical value of gain, Ku, is
reached.
3.Measure the period of oscillation to obtain the
critical time constant, Pu.
4.Use Table 2.8 to calculate the necessary PID
control parameters.
The process operator can do the nal tuning of the control
iteratively to yield satisfactory control.
A 24 V DC external supply can be used as low voltage
supply to the control card and any option cards installed.
This enables full operation of the LCP (including parameter
setting) without connection to mains.
NOTICE!
A warning of low voltage is given when 24 V DC has
been connected; however, there is no tripping.
Without galvanic isolation (type PELV), the control
terminals impose an electrical shock hazard. Failure to
follow the recommendations, may lead to death or
serious injury.
Use 24 V DC supply of type PELV to ensure
•
correct galvanic isolation (type PELV).
2.5.2 DIP Switches
2.5.3 Basic Wiring Example
Connect terminals 27 and 37 to +24 V terminals 12 and 13,
as shown in Figure 2.18.
Long control cables and analog signals may in rare cases
result in 50/60 Hz ground loops due to noise from mains
supply cables. If this occurs, it may be necessary to break
the shield or insert a 100 nF capacitor between shield and
chassis. Connect the digital and analog inputs and outputs
separately to the common inputs (terminal 20, 55, 39) to
avoid ground currents from both groups aecting other
groups. For example, switching on the digital input may
disturb the analog input signal.
2.5.5 Relay Output
The relay output with the terminals 01, 02, 03 and 04, 05,
06 has a capacity of maximum 240 V AC, 2 A. Minimum
24 V DC, 10 mA, or 24 V AC, 100 mA can be used for
indicating status and warnings. The 2 relays are physically
located on the installation card. These are programmable
through parameter group 5-4* Relays. The relays are Form C,
meaning each has 1 normally open contact and 1 normally
closed contact on a single throw. The contacts of each
relay are rated for a maximum load of 240 V AC at 2 amps.
Relay 1
Terminal 01: Common
•
Terminal 02: Normal open 240 V AC
•
Terminal 03: Normal closed 240 V AC
•
Relay 2
Terminal 04: Common
•
Terminal 05: Normal open 240 V AC
•
Terminal 06: Normal closed 240 V AC
•
Relay 1 and relay 2 are programmed in
parameter 5-40 Function Relay, parameter 5-41 On Delay,
Relay, and parameter 5-42
O Delay, Relay.
22
Figure 2.20 Input Polarity of Control Terminals
NOTICE!
To comply with EMC emission specications, shielded/
armored cables are recommended. If an unshielded/
unarmored cable is used, see chapter 2.9.7 EMC TestResults for more information.
The local reference is active when the frequency converter is operated with [Hand On] key active. Adjust the reference by
[▲]/[▼] and [◄]/[►] arrows, respectively.
Remote reference
The reference handling system for calculating the remote reference is shown in Figure 2.22.
The remote reference is calculated once in every scan
interval and initially consists of 2 types of reference
inputs:
X (the external reference): A sum (see
•
parameter 3-04 Reference Function) of up to 4
externally selected references. These comprise any
combination (determined by the setting of
parameter 3-15 Reference Resource 1,
parameter 3-16 Reference Resource 2, and
parameter 3-17 Reference Resource 3) of a xed
preset reference (parameter 3-10 Preset Reference),
variable analog references, variable digital pulse
references, and various eldbus references in the
unit, which controls the frequency converter ([Hz],
[RPM], [Nm] and so on).
Y (the relative reference): A sum of 1 xed preset
•
reference (parameter 3-14 Preset Relative Reference)
and 1 variable analog reference
(parameter 3-18 Relative Scaling ReferenceResource) in [%].
The 2 types of reference inputs are combined in the
following formula: Remote reference=X+X*Y/100%. If
relative reference is not used, set parameter 3-18 Relative
Scaling Reference Resource to [0] No function and
parameter 3-14 Preset Relative Reference to 0%. The catch
up/slow down function and the freeze reference function can
both be activated by digital inputs on the frequency
converter. The functions and parameters are described in
the VLT® AutomationDrive FC 301/FC 302 Programming
Guide.
The scalings of analog references are described in
parameter groups 6-1* Analog Input 1 and 6-2* Analog Input
2, and the scaling of digital pulse references are described
in parameter group 5-5* Pulse Input.
Reference limits and ranges are set in parameter group 3-0*Reference Limits.
22
Figure 2.23 Reference Range=[0] Min-Max
Figure 2.24 Reference Range=[1] -Max-Max
The value of parameter 3-02 Minimum Reference cannot be
set to less than 0, unless parameter 1-00 CongurationMode is set to [3] Process. In that case, the following
relations between the resulting reference (after clamping)
and the sum of all references is as shown in Figure 2.25.
2.6.1 Reference Limits
Parameter 3-00 Reference Range, parameter 3-02 Minimum
Reference, and parameter 3-03 Maximum Reference together
dene the allowed range of the sum of all references. The
sum of all references is clamped when necessary. The
relation between the resulting reference (after clamping) is
shown in Figure 2.23/Figure 2.24 and the sum of all
references is shown in Figure 2.25.
2.6.2 Scaling of Preset References and Bus References
22
Preset references are scaled according to the following
rules:
When parameter 3-00 Reference Range is set to [0]
•
Min-Max : 0% reference equals 0 [unit] where unit
can be any unit, for example RPM, m/s, bar, and
so on. 100% reference equals the maximum (abs
(parameter 3-03 Maximum Reference), abs
(parameter 3-02 Minimum Reference)).
When parameter 3-00 Reference Range: [1] -Max to
•
+Max 0% reference equals 0 [unit] -100%
reference equals -Maximum reference 100%
reference equals maximum reference.
2.6.3 Scaling of Analog and Pulse References and Feedback
References and feedback are scaled from analog and pulse
inputs in the same way. The only dierence is that a
reference above or below the specied minimum and
maximum endpoints (P1 and P2 in Figure 2.26) are
clamped whereas a feedback above or below is not.
Bus references are scaled according to the following
rules:
When parameter 3-00 Reference Range: [0] Min to
•
Max. To obtain maximum resolution on the bus
reference the scaling on the bus is: 0% reference
equals minimum reference and 100% reference
equals maximum reference.
When parameter 3-00 Reference Range: [1] -Max to
•
+Max -100% reference equals maximum reference
100% reference equals max reference.
Figure 2.26 Scaling of Analog and Pulse References and
The endpoints P1 and P2 are dened by the parameters in
Table 2.9, depending on which analog or pulse input is
used.
(RPM)
Resource output
Resource
input
Quadrant 2
Quadrant 3
Quadrant 1
Quadrant 4
Terminal X
low
Terminal X
high
Low reference/feedback
value
High reference/feedback
value
-11
130BA179.10
-1500
-66
(V)
1500
-1010
P1
P2
0
Product Overview and Functi...Design Guide
Analog 53
S201=OFF
P1=(Minimum input value, minimum reference value)
Minimum reference valueParameter 6-14
Terminal 53
Low Ref./Feedb.
Value
Minimum input valueParameter 6-10
Terminal 53
Low Voltage
[V]
P2=(Maximum input value, maximum reference value)
Maximum reference valueParameter 6-15
Terminal 53
High Ref./
Feedb. Value
Maximum input valueParameter 6-11
Terminal 53
High Voltage
[V]
Table 2.9 Input and Reference Endpoint Values
Analog 53
S201=ON
Parameter 6-14 T
erminal 53 Low
Ref./Feedb. Value
Parameter 6-12 T
erminal 53 Low
Current [mA]
Parameter 6-15 T
erminal 53 High
Ref./Feedb. Value
Parameter 6-13 T
erminal 53 High
Current [mA]
2.6.4 Dead Band Around Zero
Analog 54
S202=OFF
Parameter 6-24
Terminal 54
Low Ref./Feedb.
Value
Parameter 6-20
Terminal 54
Low Voltage
[V]
Parameter 6-25
Terminal 54
High Ref./
Feedb. Value
Parameter 6-21
Terminal 54
High
Voltage[V]
Analog 54
S202=ON
Parameter 6-24 T
erminal 54 Low
Ref./Feedb. Value
Parameter 6-22 T
erminal 54 Low
Current [mA]
Parameter 6-25 T
erminal 54 High
Ref./Feedb. Value
Parameter 6-23 T
erminal 54 High
Current[mA]
Pulse input 29 Pulse input 33
Parameter 5-52
Term. 29 Low
Ref./Feedb. Value
Parameter 5-50
Term. 29 Low
Frequency [Hz]
Parameter 5-53
Term. 29 High
Ref./Feedb. Value
Parameter 5-51
Term. 29 High
Frequency [Hz]
Parameter 5-57 Term.
33 Low Ref./Feedb.
Value
Parameter 5-55 Term.
33 Low Frequency
[Hz]
Parameter 5-58 Term.
33 High Ref./Feedb.
Value
Parameter 5-56 Term.
33 High Frequency
[Hz]
22
Sometimes the reference (in rare cases also the feedback)
should have a dead band around zero (that is, to make
sure that the machine is stopped when the reference is
near 0).
To make the dead band active and to set the amount of
dead band, the following settings must be done:
The size of the dead band is dened by either P1 or P2 as
shown in Figure 2.28.
Either minimum reference value (see Table 2.9 for
•
relevant parameter) or maximum reference value
must be 0. In other words, either P1 or P2 must
be on the X-axis in Figure 2.28.
Case 2: Positive reference with dead band, digital input to trigger reverse. Clamping rules.
22
This case shows how reference input with limits outside -maximum to +maximum limits clamps to the inputs low and high
limits before addition to external reference. The case also shows how the external reference is clamped to -maximum to
+maximum by the reference algorithm.
Case 3: Negative to positive reference with dead band, sign determines the direction, -maximum to +maximum
22
Figure 2.32 Example 3 - Positive to Negative Reference
Brake Functions
2.7
Brake function is applied for braking the load on the
motor shaft, either as dynamic brake or static braking.
NOTICE!
A frequency converter cannot provide Safe Torque O
control of a mechanical brake. A redundancy circuitry for
the brake control must be included in the installation.
2.7.1 Mechanical Brake
A mechanical holding brake mounted directly on the
motor shaft normally performs static braking. In some
applications (usually synchronous permanent motors), the
static holding torque holds the motor shaft. The holding
brake is either controlled by a PLC, directly by a relay, or a
digital output from the frequency converter.
within the electrical specication (voltage, current, and so
on) or with external relays. If the frequency converter is
congured without brake, the internal electrical control
VLT® Decentral Drive FCD 302 can be congured with or
without a brake (see position 18 in Figure 6.1).
If the inverter part is congured with brake, relay 1 can be
congured for various applications, while relay 2 should be
reserved only for the mechanical brake. Relay 2 is mounted
inside the installation box, but in this conguration state it
is not active.
The mechanical brake coil can be powered by a low
voltage (of 24 V DC) or from mains line AC voltage.
If the mechanical brake is a 24 V DC type, 1 of the 2
signal for relay 2 is active.
If the brake is powered by mains supply, or a mains
rectied DC voltage, it is recommended to order the FCD
302 with a mechanical brake. In this case, all the parameter
settings for relay 2 now control the internal solid-state
switch which gives the output voltage at the MBR+ and
MBR- terminals. In some motors, this mechanical brake can
be of AC-type or DC-type. If the unit is AC-type, the
mechanical brake has an internal diode D and the internal
MOV, as described in the electrical diagram in Figure 2.33.
custom relays, relay 1, or a functional relay 2, can be used
1Inverter part
2MBR+ terminal 122
3Mechanical brake coil
4MBR- terminal 123
5Solid state switch
6Galvanic isolated control circuit
Figure 2.33 Electrical Diagram of Mechanical Brake
The supply voltage is derived from the mains voltage
between phases L2 and L3, which is passed through a
single pulse diode rectication.
The output voltage of solid-state supply is not a constant
value, but rather a pulsed voltage with an average level
direct dependent on the mains voltage, as shown in
Figure 2.34:
22
Figure 2.35 Average Output Voltage
It is possible to supply the mechanical brake in the motor
with both DC and AC voltage. The output voltage is
rectied by the internal diode inside the mechanical brake
unit circuit. The average voltage applied to the brake coil
remains at the same value.
V
ILmInstant line voltage
Mechanical brake voltage
MBR
Figure 2.34 Instant Voltage V
with its average level of V
MBR
MBR
This rectied voltage is applied to the mechanical brake
inductor, with the smoothed current shape ILm.
The voltage shown in Figure 2.33 has the amplitude of the
line voltage and an average voltage level calculated as:
V
= 0.45 x V
MBR(DC)
AC
Examples:
VAC = 400 V
VAC = 480 V
rms
rms
⇒ V
⇒ V
= 180 VDC.
MBR
= 216 VDC.
MBR
The average level of output voltage is directly determined
by the amplitude of the line voltage measured between
phases L1 and L2.
NOTICE!
Maximum nominal voltage = 480 AC.
2.7.1.2 Mechanical Brake Control
For hoisting applications, it is necessary to be able to
control an electro-magnetic brake. For controlling the
brake, a relay output (relay 1 or relay 2/solid state brake)
or a programmed digital output (terminal 27 or 29) is
required. Normally, this output must be closed for as long
as the frequency converter is unable to hold the motor, for
example, because of excess load. For applications with an
electro-magnetic brake, select [32] mechanical brake control
in 1 of the following parameters:
Parameter 5-40 Function Relay (Array parameter),
•
Parameter 5-30 Terminal 27 Digital Output, or
•
Parameter 5-31 Terminal 29 digital Output
•
When [32] mechanical brake control is selected, the
mechanical brake relay stays closed during start until the
output current is above a preset level. Select the preset
level in parameter 2-20 Release Brake Current. During stop,
the mechanical brake closes when the speed is below the
level selected in parameter 2-21 Activate Brake Speed [RPM].
When the frequency converter is brought into an alarm
condition (that is, an overvoltage situation), or during Safe
Torque O, the mechanical brake immediately cuts in.
Figure 2.36 Mechanical Brake Control for Hoisting Applications
In hoisting/lowering applications, it must be possible to
control an electromechanical brake.
Step-by-step description
To control the mechanical brake, use any relay
•
output, digital output (terminal 27 or 29), or
solid-state brake voltage output (terminals 122–
123). Use a suitable contactor when required.
Ensure that the output is switched o as long as
•
the frequency converter is unable to drive the
motor. For example, due to the load being too
heavy, or when the motor is not yet mounted.
Select [32] mechanical brake control in parameter
•
group 5-4* Relays (or in parameter group 5-3*
Digital Outputs) before connecting the mechanical
brake.
The brake is released when the motor current
•
exceeds the preset value in
parameter 2-20 Release Brake Current.
The brake is engaged when the output frequency
•
is lower than a preset limit. Set the limit in
NOTICE!
Recommendation: For vertical lifting or hoisting
applications, ensure that the load can be stopped in an
emergency or a malfunction of a single part such as a
contactor.
When the frequency converter enters alarm mode or an
overvoltage situation, the mechanical brake cuts in.
NOTICE!
For hoisting applications, make sure that the torque limit
settings do not exceed the current limit. Set torque limits
in parameter 4-16 Torque Limit Motor Mode and
parameter 4-17 Torque Limit Generator Mode. Set current
limit in parameter 4-18 Current Limit.
Recommendation: Set parameter 14-25 Trip Delay at
Torque Limit to [0], parameter 14-26 Trip Delay at Inverter
Fault to [0], and parameter 14-10 Line Failure to [3]
Coasting.
if the frequency converter carries out a stop
command.
parameter 2-21 Activate Brake Speed [RPM] or
parameter 2-22 Activate Brake Speed [Hz] and only
To reduce the electrical noise from the wires between the
mechanical brake and the frequency converter, the wires
must be twisted.
For enhanced EMC performance, use a metal shield.
Twisted-pair cables, containing both the motor and brake
cables, can be used.
2.7.1.4 Hoist Mechanical Brake
For an example of advanced mechanical brake control for
hoisting applications, see chapter 4 Application Examples.
2.7.2 Dynamic Brake
Dynamic brake established by:
Resistor brake: A brake IGBT keeps the
•
overvoltage under a certain threshold by
directing the brake energy from the motor to the
connected brake resistor (parameter 2-10 BrakeFunction = [1] Resistor Brake).
AC brake: The brake energy is distributed in the
•
motor by changing the loss conditions in the
motor. The AC brake function cannot be used in
applications with high cycling frequency since
this overheats the motor (parameter 2-10 BrakeFunction = [2] AC Brake).
DC brake: An overmodulated DC current added to
•
the AC current works as an eddy current brake
(parameter 2-02 DC Braking Time≠ 0 s).
numbers can be found in chapter 6.2.1 Ordering Numbers:Accessories.
2.7.2.2 Selection of Brake Resistor
To handle higher demands by generatoric braking, a brake
resistor is necessary. Using a brake resistor ensures that the
energy is absorbed in the brake resistor and not in the
frequency converter. For more information, see the VLTBrake Resistor MCE 101 Design Guide.
If the amount of kinetic energy transferred to the resistor
in each braking period is not known, the average power
can be calculated based on the cycle time and braking
time also called intermittent duty cycle. The resistor
intermittent duty cycle is an indication of the duty cycle at
which the resistor is active. Figure 2.37 shows a typical
braking cycle.
®
NOTICE!
Motor suppliers often use S5 when stating the allowed
load, which is an expression of intermittent duty cycle.
The intermittent duty cycle for the resistor is calculated as
follows:
Duty cycle=tb/T
T=cycle time in s.
tb is the braking time in s (of the cycle time).
22
2.7.2.1 Brake Resistors
In certain applications, break down of kinetic energy is
required. In this frequency converter, the energy is not fed
back to the grid. Instead, the kinetic energy must be
transformed to heat, and this is achieved by braking using
a brake resistor.
In applications where the motor is used as a brake, energy
is generated in the motor and sent back into the
frequency converter. If the energy cannot be transported
back to the motor, it increases the voltage in the frequency
converter DC-line. In applications with frequent braking
and/or high inertia loads, this increase may lead to an
overvoltage trip in the frequency converter and nally a
shutdown. Brake resistors are used to dissipate the excess
energy resulting from the regenerative braking. The resistor
is selected in respect to its ohmic value, its power
dissipation rate, and its physical size. Danfoss brake
resistors are available in several types, for internal or
external installation to the frequency converter. Code
Brake resistors have a duty cycle of 5%, 10%, and 40%. If a
22
10% duty cycle is applied, the brake resistors are able to
absorb brake power for 10% of the cycle time. The
remaining 90% of the cycle time is used on dissipating
excess heat.
NOTICE!
NOTICE!
If a short circuit in the brake transistor occurs, power
dissipation in the brake resistor is only prevented by
using a mains switch or contactor to disconnect the
mains for the frequency converter (The contactor can be
controlled by the frequency converter).
Ensure that the resistor is designed to handle the
required braking time.
NOTICE!
Do not touch the brake resistor as it can get very hot
The maximum allowed load on the brake resistor is stated
as a peak power at a given intermittent duty cycle and can
while/after braking. The brake resistor must be placed in
a secure environment to avoid re risk.
be calculated as:
2
U
Rbr Ω =
dc
P
peak
where
P
peak=Pmotor
x Mbr [%] x η
motor
x η
VLT
[W]
The brake resistance depends on the DC-link voltage (Udc).
The brake function is settled in 4 areas of mains.
2.7.2.3 Brake Resistors 10 W
For frequency converters equipped with the dynamic brake
option, 1 brake IGBT along with terminals 81 (R-) and 82 (R
+) is included in each inverter module for connecting a
brake resistor(s).
An internal 10 W brake resistor can be mounted in the
installation box (bottom part). This optional resistor is
SizeBrake activeWarning
before cutout
FCD 302
3x380–480 V
Table 2.11 Brake Limit Values
778 V810 V820 V
NOTICE!
Check that the brake resistor can cope with a voltage of
Cutout (trip)
suitable for applications where braking IGBT is only active
for very short duty cycles, for example to avoid warning
and trip events.
For internal brake resistor use:
Brake resistor 1750 Ω 10 W/
100%
Brake resistor 350 Ω 10 W/
100%
For mounting inside installation
box, below motor terminals.
For mounting inside installation
box, below motor terminals.
820 V - unless brake resistors are used.
Table 2.12 Brake Resistors 10 W
Danfoss recommends that the brake resistance R
guarantees that the frequency converter is able to brake at
the highest brake power (M
) of 160%. The formula can
br(%)
be written as:
2
U
x100
Ω =
R
η
η
rec
motor
VLT
P
motor
is typically at 0.90
is typically at 0.98
For 480 V frequency converters, R
xM
dc
br( % )
xη
VLT
xη
motor
at 160% brake power
rec
is written as:
480
V: R
rec
375300
=
P
motor
Ω
rec
2.7.2.4 Brake Resistor 40%
Placing the brake resistor externally has the advantages of
selecting the resistor based on application need,
dissipating the energy outside of the control panel, and
protecting the frequency converter from overheating if the
brake resistor is overloaded.
NumberFunction
81 (optional function)R-Brake resistor terminals
82 (optional function)R+
Table 2.13 Brake Resistors 40%
NOTICE!
The connection cable to the brake resistor must
The resistance in the the brake resistor circuit should not
exceed the limits recommended by Danfoss. If a brake
resistor with a higher ohmic value is selected, the 160%
brake power may not be achieved because there is a risk
that the frequency converter cuts out for safety reasons.
•
be shielded/armored. Connect the shield to the
metal cabinet of the frequency converter and to
the metal cabinet of the brake resistor with cable
clamps.
The brake is protected against short-circuiting of the brake
resistor, and the brake transistor is monitored to ensure
that short-circuiting of the transistor is detected. A relay/
digital output can be used for protecting the brake resistor
against overloading in connection with a fault in the
frequency converter.
In addition, the brake makes it possible to readout the
momentary power and the mean power for the latest
120 s. The brake can also monitor the energizing power
and make sure that it does not exceed a limit selected in
parameter 2-12 Brake Power Limit (kW). In
parameter 2-13 Brake Power Monitoring, select the function
to carry out when the power transmitted to the brake
resistor exceeds the limit set in parameter 2-12 Brake PowerLimit (kW).
NOTICE!
Monitoring the brake power is not a safety function; a
thermal switch is required for that purpose. The brake
resistor circuit is not ground leakage protected.
Overvoltage control (OVC) (exclusive brake resistor) can be
selected as an alternative brake function in
parameter 2-17 Over-voltage Control. This function is active
for all units. The function ensures that a trip can be
avoided if the DC-link voltage increases. This is done by
increasing the output frequency to limit the voltage from
the DC link. It is a very useful function to avoid
unnecessary tripping of the frequency converter, for
example when the ramp-down time is too short. In this
situation, the ramp-down time is extended.
NOTICE!
OVC cannot be activated when running a PM motor
(when parameter 1-10 Motor Construction is set to [1] PMnon-salient SPM).
2.7.2.6 Brake Resistor Cabling
For enhanced EMC performance, use a metal shield.
2.8 Safe Torque O
To run STO, additional wiring for the frequency converter is
required. Refer to VLT® Frequency Converters Safe Torque OOperating Guide for further information.
2.9 EMC
2.9.1 General Aspects of EMC Emissions
Burst transient is usually conducted at frequencies in the
range 150 kHz to 30 MHz. Airborne interference from the
frequency converter system in the range 30 MHz to 1 GHz
is generated from the inverter, motor cable, and the motor.
Capacitive currents in the motor cable coupled with a high
dU/dt from the motor voltage generate leakage currents.
The use of a shielded motor cable increases the leakage
current (see Figure 2.38) because shielded cables have
higher capacitance to ground than unshielded cables. If
the leakage current is not ltered, it causes greater
interference on the mains in the radio frequency range
below approximately 5 MHz. Since the leakage current (I1)
is carried back to the unit through the shield (I3), there is
only a small electro-magnetic eld (I4) from the shielded
motor cable.
The shield reduces the radiated interference but increases
the low-frequency interference on the mains. Connect the
motor cable shield to the frequency converter and motor
enclosures. Use integrated shield clamps to avoid twisted
shield ends (pigtails). Twisted shield ends increase the
shield impedance at higher frequencies, which reduces the
shield eect and increases the leakage current (I4).
When a shielded cable is used for eldbus relay, control
cable, signal interface, or brake, ensure that the shield is
mounted on the enclosure at both ends. In some
situations, however, it is necessary to break the shield to
avoid current loops.
22
EMC (twisted cable/shielding)
To reduce the electrical noise from the wires between the
brake resistor and the frequency converter, the wires must
be twisted.
Mounting plates, when used, must be constructed of metal
to ensure that the shield currents are conveyed back to the
unit. Ensure good electrical contact from the mounting
plate through the mounting screws to the chassis of the
frequency converter.
When unshielded cables are used, some emission
requirements are not fullled. However, the immunity
requirements are observed.
To reduce the interference level from the entire system
(unit+installation), keep motor and brake cables as short as
possible. Avoid placing cables with a sensitive signal level
alongside motor and brake cables. Radio interference
frequency above 50 MHz (airborne) is generated by the
control electronics in particular.
According to the EMC product standard for adjustable speed frequency converters EN/IEC 61800-3:2004 the EMC
requirements depend on the intended use of the frequency converter. Four categories are dened in the EMC product
standard. The denitions of the 4 categories together with the requirements for mains supply voltage conducted emissions
are given in Table 2.14.
Conducted emission requirement
CategoryDenition
C1Frequency converters installed in the 1st environment (home and oce) with a
supply voltage less than 1000 V.
C2Frequency converters installed in the 1st environment (home and oce) with a
supply voltage less than 1000 V, which are neither plug-in nor movable and are
intended to be installed and commissioned by a professional.
C3Frequency converters installed in the 2nd environment (industrial) with a supply
voltage lower than 1000 V.
C4Frequency converters installed in the 2nd environment with a supply voltage equal
to or above 1000 V or rated current equal to or above 400 A or intended for use in
complex systems.
according to the limits given in EN
55011
Class B
Class A Group 1
Class A Group 2
No limit line.
An EMC plan should be made.
22
Table 2.14 Emission Requirements
When the generic emission standards are used, the frequency converters are required to comply with the limits in Table 2.15.
Conducted emission requirement
EnvironmentGeneric standard
First environment
(home and oce)
Second environment
(Industrial environment)
Table 2.15 Emission Limit Classes
EN/IEC 61000-6-3 Emission standard for residential, commercial,
and light industrial environments.
EN/IEC 61000-6-4 Emission standard for industrial environments.Class A Group 1
The immunity requirements for frequency converters
depend on the environment where they are installed. The
requirements for the industrial environment are higher
than the requirements for the home and oce
environment. All Danfoss frequency converters comply
with the requirements for the industrial environment and
consequently comply also with the lower requirements for
home and oce environment with a large safety margin.
To document immunity against burst transient from
electrical phenomena, the following immunity tests have
been made on a system consisting of a frequency
converter (with options if relevant), a shielded control
cable, and a control box with potentiometer, motor cable,
and motor.
:
The tests were performed in accordance with the following
basic standards
See Table 2.16.
EN 61000-4-2 (IEC 61000-4-2): Electrostatic
•
discharges (ESD): Simulation of electrostatic
discharges from human beings.
EN 61000-4-3 (IEC 61000-4-3): Incoming electro-
•
magnetic eld radiation, amplitude modulated
simulation of the eects of radar and radio
communication equipment and mobile communications equipment.
EN 61000-4-4 (IEC 61000-4-4): Burst transients:
•
Simulation of interference brought about by
switching a contactor, relay, or similar devices.
EN 61000-4-5 (IEC 61000-4-5): Surge transients:
•
Simulation of transients brought about for
example, by lightning that strikes near installations.
EN 61000-4-6 (IEC 61000-4-6): RF common
•
mode: Simulation of the eect from radiotransmission equipment joined by connection
cables.
The following is a guideline to good engineering practice
when installing frequency converters. Follow these
guidelines to comply with EN 61800-3 First environment. If
the installation is in EN 61800-3 Second environment, for
example industrial networks, or in an installation with its
own transformer. Deviation from these guidelines is
allowed but not recommended. See also chapter 1.5.1 CELabeling, chapter 2.9.1 General Aspects of EMC Emissions,
and chapter 2.9.7 EMC Test Results.
Good engineering practice to ensure EMC-correct
electrical installation:
Use only braided shielded/armored motor cables
•
and braided shielded/armored control cables. The
shield should provide a minimum coverage of
80%. The shield material must be metal, not
limited to but typically copper, aluminum, steel,
or lead. There are no special requirements for the
mains cable.
Installations using rigid metal conduits are not
•
required to use shielded cable, but the motor
cable must be installed in conduit separate from
the control and mains cables. Full connection of
the conduit from the frequency converter to the
motor is required. The EMC performance of
exible conduits varies a lot and information from
the manufacturer must be obtained.
Connect the shield/armor/conduit to ground at
•
both ends for motor cables and for control
cables. Sometimes, it is not possible to connect
the shield in both ends. If so, connect the shield
at the frequency converter.
Avoid terminating the shield/armor with twisted
•
ends (pigtails). It increases the high frequency
impedance of the shield, which reduces its
eectiveness at high frequencies. Use low
impedance cable clamps or EMC cable glands
instead.
Avoid using unshielded/unarmored motor or
•
control cables inside cabinets housing the
frequency converter(s), whenever this can be
avoided.
Leave the shield as close to the connectors as possible.
Figure 2.39 shows an example of an EMC-correct electrical
installation of the VLT® Decentral Drive FCD 302. The
frequency converter is connected to a PLC, which is
installed in a separate cabinet. Other ways of doing the
installation may have just as good an EMC performance,
provided the above guidelines are followed.
If the installation is not carried out according to the
guidelines, and if unshielded cables and control wires are
used, then certain emission requirements are not
although the immunity requirements are fullled. See
chapter 2.9.7 EMC Test Results.
Min. 200mm
between control cables,
motor cable and
Motor cable
Motor, 3 phases and
PLC etc.
Mains-supply
mains cable
PLC
Protective earth
Reinforced protective earth
Product Overview and Functi...
VLT® Decentral Drive FCD 302
22
Figure 2.39 EMC-correct Electrical Installation of a Frequency Converter
A minimum distance of 200 mm (7.87 in) is required
between the eldbus cable and the motor cable and also
between eldbus cable and the mains cable. If this cannot
be achieved, use the optional PE grounding plug on the
To obtain the electrical safety, always connect the safety
ground on the dedicated connections inside the VLTDecentral Drive FCD 302 installation box. See Figure 2.41.
®
Equalizing cable
As the shield of the communication cable needs to be
connected to ground by each drive/device, there is a risk
of having current in the communication cable. This might
lead to communication problems as the equalizing current
can interfere with the communication. To reduce currents
in the shield of the communication cable, always apply a
short grounding cable between units that are connected
to the same communication cable. Danfoss recommend
using minimum 16 mm2 (6 AWG) equalizing cable and
install the equalizing cable parallel with the communication cable.
®
For good equalizing between VLT
in a decentral installation, use the external equalizing
terminal from Danfoss (ordering number 130B5833).
Decentral Drive FCD 302
2.9.4.2 Use of EMC-correct Cables
Danfoss recommends braided shielded/armored cables to
optimize EMC immunity of the control cables and emission
from the motor cables.
The ability of a cable to reduce the in- and outgoing
radiation of electric noise depends on the transfer
impedance (ZT). The shield of a cable is normally designed
to reduce the transfer of electric noise; however, a shield
with a lower transfer impedance (ZT) value is more
eective than a shield with a higher transfer impedance
(ZT).
Transfer impedance (ZT) is rarely stated by cable manufacturers but it is often possible to estimate transfer
impedance (ZT) by assessing the physical design of the
cable.
Transfer impedance (ZT) can be assessed based on the
following factors:
The conductibility of the shield material.
•
The contact resistance between the individual
•
shield conductors.
The shield coverage, that is, the physical area of
•
the cable covered by the shield - often stated as
a percentage value.
With very long control cables, ground loops may occur. To
eliminate ground loops, connect 1 end of the shield-toground with a 100 nF capacitor (keeping leads short).
a.Aluminum-clad with copper wire
b.Twisted copper wire or armored steel wire cable
c.Single-layer braided copper wire with varying percentage
shield coverage. This is the typical reference cable
d.Double-layer braided copper wire
e.Twin layer of braided copper wire with a magnetic,
shielded/armored intermediate layer
f.Cable that runs in copper tube or steel tube
g.Lead cable with 1.1 mm (0.04 inch) wall thickness
Figure 2.42 Transfer Impedance
2.9.4.3 Grounding of Shielded Control
Cables
Correct shielding
The preferred method usually is to secure control cables
and cables with shielding clamps provided at both ends to
ensure best possible high frequency cable contact.
If the ground potential between the frequency converter
and the PLC is dierent, electric noise may occur that
disturbs the entire system. Solve this problem by tting an
equalizing cable next to the control cable. Minimum cable
cross-section: 16 mm2 (6 AWG).
Figure 2.44 Shielding for 50/60 Hz Ground Loops
Avoid EMC noise on serial communication
This terminal is connected to ground via an internal RC
link. Use twisted-pair cables to reduce interference
between conductors. The recommended method is shown
in Figure 2.45.
1
Minimum 16 mm2 (6 AWG)
2Equalizing cable
Figure 2.45 Shielding for EMC Noise Reduction, Serial
Alternatively, the connection to terminal 61 can be
omitted:
1
Minimum 16 mm2 (6 AWG)
2Equalizing cable
Figure 2.46 Shielding for EMC Noise Reduction, Serial
Communication, without Terminal 61
2.9.4.4 RFI Switch
Mains supply isolated from ground
When the frequency converter is supplied from an isolated
mains source (IT mains,
oating delta, and grounded delta)
or TT/TN-S mains with grounded leg, set the RFI switch to
[O] via parameter 14-50 RFI 1 on the frequency converter.
Otherwise, set parameter 14-50 RFI 1 to [On].
For further information, refer to:
IEC 364-3.
•
Application note VLT® on IT mains. It is important
•
to use isolation monitors that are capable for use
together with power electronics (IEC 61557-8).
2.9.5 Mains Supply Interference/Harmonics
A frequency converter takes up a non-sinusoidal current
from mains, which increases the input current I
sinusoidal current is transformed with a Fourier analysis
and split up into sine-wave currents with dierent
frequencies, that is, dierent harmonic currents IN with
50 Hz as the basic frequency:
RMS
. A non-
The harmonics do not aect the power consumption
directly but increase the heat losses in the installation
(transformer, cables). Therefore, in plants with a high
percentage of rectier load, maintain harmonic currents at
a low level to avoid overload of the transformer and high
temperature in the cables.
Figure 2.47 DC-link Coils
NOTICE!
Some of the harmonic currents might disturb communication equipment connected to the same transformer or
cause resonance in connection with power factor
correction batteries.
Input current
I
RMS
I
1
I
5
I
7
I
11-49
Table 2.18 Harmonic Currents Compared to
the RMS Input Current
To ensure low harmonic currents, the frequency converter
is equipped with DC-link coils as standard. DC coils reduce
the total harmonic distortion (THD) to 40%.
2.9.5.1 Eect of Harmonics in a Power
Distribution System
In Figure 2.48, a transformer is connected on the primary
side to a point of common coupling PCC1 on the medium
voltage supply. The transformer has an impedance Z
feeds a number of loads. The point of common coupling
where all loads are connected together is PCC2. Each load
is connected through cables that have an impedance Z1,
Z2, Z3.
Figure 2.48 Small Distribution System
Harmonic currents drawn by non-linear loads cause
distortion of the voltage because of the voltage drop on
the impedances of the distribution system. Higher
impedances result in higher levels of voltage distortion.
Current distortion relates to apparatus performance and it
relates to the individual load. Voltage distortion relates to
system performance. It is not possible to determine the
voltage distortion in the PCC knowing only the load’s
harmonic performance. To predict the distortion in the
PCC, the conguration of the distribution system and
relevant impedances must be known.
A commonly used term for describing the impedance of a
grid is the short circuit ratio R
between the short circuit apparent power of the supply at
the PCC (Ssc) and the rated apparent power of the load
(S
).
equ
S
sce
ce
=
S
equ
Ssc=
Z
2
U
supply
and
S
R
where
, dened as the ratio
sce
= U × I
equ
equ
xfr
and
The negative eect of harmonics is twofold
Harmonic currents contribute to system losses (in
•
cabling, transformer).
Harmonic voltage distortion causes disturbance
•
to other loads and increase losses in other loads.
Figure 2.49 Negative Eects of Harmonics
2.9.5.2 Harmonic Limitation Standards and
Requirements
The requirements for harmonic limitation can be:
Application-specic requirements.
•
Standards that must be observed.
•
The application-specic requirements are related to a
specic installation where there are technical reasons for
limiting the harmonics.
Example: A 250 kVA transformer with 2 110 kW motors
connected is sucient if 1 of the motors is connected
directly online and the other is supplied through a
frequency converter. However, the transformer is
undersized if a frequency converter supplies both motors.
Using extra means of harmonic reduction within the installation or selecting low harmonic frequency converter
variants makes it possible for both motors to run with
frequency converters.
There are various harmonic mitigation standards,
regulations, and recommendations. Dierent standards
apply in dierent geographical areas and industries. The
following standards are the most common:
IEC61000-3-2
•
IEC61000-3-12
•
IEC61000-3-4
•
IEEE 519
•
G5/4
•
See the VLT® Advanced Harmonic Filter AHF 005 & AHF 010
Design Guide for specic details on each standard.
Determining the degree of voltage pollution on the grid and needed precaution is done with the Danfoss VLT® Harmonic
Calculation MCT 31 software. The free tool MCT 31 can be downloaded from www.danfoss.com. The software is built with a
focus on user-friendliness and limited to involve only system parameters that are normally accessible.
2.9.6 Residual Current Device
22
Use RCD relays, multiple protective earthing, or grounding as extra protection to comply with local safety regulations.
If a ground fault appears, a DC content may develop in the faulty current.
If RCD relays are used, local regulations must be observed. Relays must be suitable for protection of 3-phase equipment
with a bridge rectier and for a brief discharge on power-up using RCDs.
2.9.7 EMC Test Results
The following test results have been obtained using a system with a frequency converter (with options if relevant), a
shielded control cable, a control box with potentiometer, a motor, and motor shielded cable.
RFI lter typeConducted emissionRadiated emission
Standards and
requirements
H1
FCD 302
EN 55011Class BClass A Group 1Class A Group 2Class BClass A Group 1
The frequency converter meets the IEC/EN 60068-2-3
standard, EN 50178 section 9.4.2.2 at 50 °C (122 °F).
3.1.2 Aggressive Environments
A frequency converter contains many mechanical and
electronic components. All are to some extent vulnerable
to environmental eects.
NOTICE!
The frequency converter should not be installed in
environments with airborne liquids, particles, or gases
capable of aecting and damaging the electronic
components. Failure to take the necessary protective
measures increases the risk of stoppages, thus reducing
the life of the frequency converter.
Degree of protection as per IEC 60529
In environments with high temperatures and humidity,
corrosive gases such as sulphur, nitrogen, and chlorine
compounds cause chemical processes on the frequency
converter components.
Such chemical reactions rapidly aect and damage the
electronic components. In such environments, mount the
equipment in a cabinet with fresh air ventilation, keeping
aggressive gases away from the frequency converter.
An extra protection in such areas is a coating of the
printed circuit boards, which can be ordered as an option.
NOTICE!
Mounting frequency converters in aggressive
environments increases the risk of stoppages and considerably reduces the life of the frequency converter.
3.1.3 Vibration and Shock
The frequency converter has been tested according to the
procedure based on the shown standards:
The frequency converter complies with requirements that
exist for units mounted on the walls and oors of
production premises, and in panels bolted to walls or
oors.
IEC/EN 60068-2-6: Vibration (sinusoidal) - 1970
•
IEC/EN 60068-2-64: Vibration, broad-band random
•
3.1.4 Acoustic Noise
The acoustic noise from the frequency converter comes
from these sources:
DC intermediate circuit coils.
•
RFI lter choke.
•
VLT® Decentral Drive FCD 302 has no signicant audible
noise. Refer to chapter 7 Specications for acoustic noise
data.
Mounting Positions
3.2
The VLT® Decentral Drive FCD 302 consists of 2 parts:
The installation box
•
The electronic part
•
Standalone mounting
The holes on the rear of the installation box are
•
used to x mounting brackets.
Ensure that the strength of the mounting location
•
can support the unit weight.
Make sure that the proper mounting screws or
•
bolts are used.
Before installing the frequency converter, check the
ambient air for liquids, particles, and gases. This is done by
observing existing installations in this environment. Typical
indicators of harmful airborne liquids are water or oil on
metal parts, or corrosion of metal parts.
Excessive dust particle levels are often found on installation cabinets and existing electrical installations. One
indicator of aggressive airborne gases is blackening of
copper rails and cable ends on existing installations.
Figure 3.1 FCD 302 Stand-alone Mounted with Mounting
Brackets
3.2.1 Mounting Positions for Hygienic
Installation
The VLT® Decentral Drive FCD 302 is designed according to
the EHEDG guidelines, suitable for installation in
environments with high focus on ease of cleaning.
Mount the FCD 302 vertically on a wall or machine frame,
to ensure that liquids drain o the enclosure. Orient the
unit so the cable glands are located at the base.
Use cable glands designed to meet hygienic application
requirements, for example Rittal HD 2410.110/120/130.
Hygienic-purpose cable glands ensure optimal ease of
cleaning the installation.
NOTICE!
Only frequency converters congured as hygienic
enclosure designation, FCD 302 P XXX T4 W69, have the
EHEDG certication.
33
Allowed mounting positions
Figure 3.3 Allowed Mounting Positions for Hygienic
Applications
Figure 3.2 Allowed Mounting Positions for Standard
Cables general
All cabling must comply with national and local
regulations on cable cross-sections and ambient
temperature. Copper (75 °C (175 °F)) conductors are
recommended.
1 Looping terminals
3.3.1.2 Connection to Mains and
Grounding
For installation instructions and location of terminals, refer
®
Decentral Drive FCD 302 Operating Guide.
to VLT
Connection of mains
Figure 3.5 Large Unit only: Service Switch at Mains with
Looping Terminals
1 Looping terminals
2 Circuit breaker
Figure 3.4 Large Unit only: Circuit Breaker and Mains
Disconnect
Figure 3.6 Motor and Connection of Mains with Service Switch
For both small and large units, the service switch is
optional. The switch is shown mounted on the motor side.
Alternatively, the switch can be on the mains side, or
omitted.
For the large unit, the circuit breaker is optional. The large
unit can be congured with either service switch or circuit
breaker, not both. Figure 3.6 is not congurable in practice,
but shows the respective positions of components only.
Usually, the power cables for mains are unshielded cables.
System IntegrationDesign Guide
3.3.1.3 Relay Connection
To set relay output, see parameter group 5-4* Relays.
NumberDescription
01-02Make (normally open)
01-03Break (normally closed)
04-05Make (normally open)
04-06Break (normally closed)
Table 3.1 Relay Settings
For location of relay terminals, refer to VLT® Decentral Drive
FCD 302 Operating Guide.
3.3.2 Fuses and Circuit Breakers
3.3.2.1 Fuses
Fuses and/or circuit breakers are recommended protection
on the supply side, if a component break-down inside the
frequency converter (rst fault) occurs.
NOTICE!
Using fuses and/or circuit breakers is mandatory in order
to ensure compliance with IEC 60364 for CE or NEC 2009
for UL.
NOTICE!
Personnel and property must be protected against the
consequence of component break-down internally in the
frequency converter.
3.3.2.2 Recommendations
CAUTION
In the event of malfunction, failure to follow the
recommendation may result in personnel risk and
damage to the frequency converter and other
equipment.
The following sections list the recommended rated current.
Danfoss recommends fuse type gG and Danfoss CB
(Danfoss - CTI-25M) circuit breakers. Other types of circuit
breakers may be used if they limit the energy into the
frequency converter to a level equal to or lower than the
Danfoss CB types.
Follow the recommendations for fuses and circuit breakers
to ensure that any damage to the frequency converter is
internal only.
For further information, see Application Note Fuses andCircuit Breakers.
3.3.2.3 CE Compliance
Use of fuses or circuit breakers is mandatory to comply
with IEC 60364.
Danfoss recommends fuse size up to gG-25. This fuse size
is suitable for use on a circuit capable of delivering
100000 A
the frequency converter short-circuit current rating (SCCR)
is 100000 A
3.3.2.4 UL Compliance
(symmetrical), 480 V. With the proper fusing,
rms
.
rms
33
Branch circuit protection
To protect the installation against electrical and re hazard,
all branch circuits in an installation, switchgear, machines,
and so on, must be protected against short circuit and
overcurrent according to national/international regulations.
NOTICE!
The recommendations given do not cover branch circuit
protection for UL.
Fuses or circuit breakers are mandatory to comply with
NEC 2009. To meet UL/cUL requirements, use the pre-fuses
in Table 7.2, and comply with the conditions listed in
chapter 7.2 Electrical Data and Wire Sizes.
The current and voltage ratings are also valid for UL.
Electrical Output: Motor-side Dynamics
3.4
3.4.1 Motor Connection
Short-circuit protection
Danfoss recommends using the fuses/circuit breakers
mentioned below to protect service personnel and
property in case of component break-down in the
frequency converter.
To comply with EMC emission specications, shielded/
armored cables are recommended.
See chapter 7.3 General Specications for correct
dimensioning of motor cable cross-section and length.
U
1
V
1
W
1
175ZA114.11
969798
969798
FC
FC
Motor
Motor
U
2
V
2
W
2
U
1
V
1
W
1
U
2
V
2
W
2
System Integration
VLT® Decentral Drive FCD 302
Shielding of cables
Avoid installation with twisted shield ends (pigtails). They
spoil the shielding eect at higher frequencies. If it is
necessary to break the shield to install a motor isolator or
33
motor contactor, the shield must be continued at the
lowest possible HF impedance.
Connect the motor cable shield to both the decoupling
plate of the frequency converter and to the metal housing
of the motor.
Make the shield connections with the largest possible
surface area (cable clamp). This is done by using the
supplied installation devices in the frequency converter.
If it is necessary to split the shield to install a motor
Figure 3.7 Star - Delta Grounding Connections
isolator or motor relay, the shield must be continued with
the lowest possible HF impedance.
NOTICE!
Cable length and cross-section
The frequency converter has been tested with a given
length of cable and a given cross-section of that cable. If
the cross-section is increased, the cable capacitance - and
thus the leakage current - may increase, and the cable
length must be reduced correspondingly. Keep the motor
cable as short as possible to reduce the noise level and
leakage currents.
All types of 3-phase asynchronous standard motors can be
connected to the frequency converter. Normally, small
motors are star-connected (230/400 V, Y). Large motors are
normally delta-connected (400/690 V, Δ). Refer to the
motor nameplate for correct connection mode and
voltage.
For installation of mains and motor cables, refer to VLT
®
Decentral Drive FCD 302 Operating Guide.
In motors without phase insulation paper or other
insulation reinforcement suitable for operation with
voltage supply (such as a frequency converter), t a sinewave lter on the output of the frequency converter.
The frequency converter is available with optional
Service switch on mains side or motor side
•
33
or
Built-in circuit breaker on the mains side (large
•
Terminal U/T1/96 connected to U-phase.
•
Terminal V/T2/97 connected to V-phase.
•
Terminal W/T3/98 connected to W-phase.
•
unit only)
Specify the requirement when ordering.
Figure 3.9 and Figure 3.10 show examples of conguration
for the large unit.
Figure 3.9 Location of Service Switch, Mains Side, Large Unit
(IP66/Type 4X indoor)
Figure 3.10 Location of Circuit Breaker, Mains Side, Large Unit
3.4.3 Additional Motor Information
3.4.3.1 Motor Cable
The motor must be connected to terminals U/T1/96, V/
T2/97, W/T3/98. Ground to terminal 99. All types of 3phase asynchronous standard motors can be used with a
frequency converter unit. The factory setting is for
clockwise rotation with the frequency converter output
connected as shown in Table 3.3:
Figure 3.11 Motor Connection - Direction of Rotation
The direction of rotation can be changed by switching 2
phases in the motor cable or by changing the setting of
parameter 4-10 Motor Speed Direction.
Motor rotation check can be performed using
parameter 1-28 Motor Rotation Check and following the
steps shown in the display.
3.4.3.2 Motor Thermal Protection
The electronic thermal relay in the frequency converter has
received UL approval for single motor overload protection,
when parameter 1-90 Motor Thermal Protection is set for
Ground
ETR Trip and parameter 1-24 Motor Current is set to the
rated motor current (see motor nameplate).
System IntegrationDesign Guide
3.4.3.3 Parallel Connection of Motors
The frequency converter can control several parallelconnected motors. When using parallel motor connection,
observe the following:
Recommended to run applications with parallel
•
motors in U/F mode parameter 1-01 Motor Control
Principle [0]. Set the U/F graph in
parameter 1-55 U/f Characteristic - U and
parameter 1-56 U/f Characteristic - F.
VVC+ mode may be used in some applications.
•
The total current consumption of the motors
•
must not exceed the rated output current I
the frequency converter.
If motor sizes are widely dierent in winding
•
resistance, starting problems may occur due to
too low motor voltage at low speed.
The electronic thermal relay (ETR) of the
•
frequency inverter cannot be used as motor
overload protection for the individual motor.
Provide further motor overload protection with
for example thermistors in each motor winding or
individual thermal relays. Circuit breakers are not
suitable as protection device.
INV
for
NOTICE!
Installations with cables connected in a common joint as
shown in the rst example in the picture is only
recommended for short cable lengths.
NOTICE!
When motors are connected in parallel,
parameter 1-02 Flux Motor Feedback Source cannot be
used, and parameter 1-01 Motor Control Principle must be
set to Special motor characteristics (U/f ).
The total motor cable length specied in chapter 7 Speci-
cations, is valid as long as the parallel cables are kept short
(less than 10 m (32.8 ft) each).
3.4.3.4 Motor Insulation
For motor cable lengths ≤ the maximum cable length
listed in chapter 7.3 General Specications, the following
motor insulation ratings are recommended because the
peak voltage can be up to twice the DC-link voltage, 2.8
times the mains voltage, due to transmission line eects in
the motor cable. If a motor has lower insulation rating, it is
recommended to use a dU/dt or sine-wave lter.
Nominal mains voltageMotor insulation
UN≤420 V
420 V<UN≤500 VReinforced ULL=1600 V
Table 3.4 Mains Voltage and Motor Insulation
Standard ULL=1300 V
3.4.3.5 Motor Bearing Currents
To minimize DE (Drive End) bearing and shaft currents
proper grounding of the frequency converter, motor,
driven machine, and motor to the driven machine is
required.
Standard mitigation strategies
1.Use an insulated bearing.
2.Apply rigorous installation procedures:
2aEnsure that the motor and load motor
are aligned.
2bStrictly follow the EMC Installation
guideline.
2cReinforce the PE so the high frequency
impedance is lower in the PE than the
input power leads.
2dProvide a good high frequency
connection between the motor and the
frequency converter, for instance via a
shielded cable which has a 360°
connection in the motor and the
frequency converter.
2eMake sure that the impedance from the
frequency converter to the building
ground is lower than the grounding
impedance of the machine. This can be
dicult for pumps.
2fMake a direct ground connection
between the motor and load motor.
3.Lower the IGBT switching frequency.
4.
Modify the inverter waveform, 60° AVM vs.
SFAVM.
5.Install a shaft grounding system or use an
isolating coupling.
6.Apply conductive lubrication.
7.Use minimum speed settings if possible.
8.Try to ensure that the mains voltage is balanced
to ground. This can be dicult for IT, TT, TN-CS,
or grounded leg systems.
The frequency converter is protected against short circuits
33
with current measurement in each of the 3 motor phases
or in the DC link. A short circuit between 2 output phases
causes an overcurrent in the inverter. The inverter is turned
o individually when the short-circuit current exceeds the
allowed value (Alarm 16, Trip Lock).
To protect the frequency converter against a short circuit
at the load sharing and brake outputs, see the design
guidelines.
Switching on the output
Switching on the output between the motor and the
frequency converter is fully allowed. No damage to the
frequency converter can occur by switching on the output.
However, fault messages can appear.
Motor-generated overvoltage
The voltage in the DC link is increased when the motor
acts as a generator, in the following cases:
The load drives the motor (at constant output
•
frequency from the frequency converter), that is,
the load generates energy.
During deceleration (ramp-down), if the inertia
•
moment is high, the friction is low, and the rampdown time is too short for the energy to be
dissipated as a loss in the frequency converter,
the motor, and the installation.
Incorrect slip compensation setting can cause
•
higher DC-link voltage.
Back EMF from PM motor operation. When
•
coasted at high RPM, the PM motor back EMF can
potentially exceed the maximum voltage
tolerance of the frequency converter and cause
damage. The frequency converter is designed to
prevent the occurrence of back EMF: The value of
parameter 4-19 Max Output Frequency is automatically limited based on an internal calculation
based on the value of parameter 1-40 Back EMF at1000 RPM, parameter 1-25 Motor Nominal Speed,
and parameter 1-39 Motor Poles.
When motor overspeed is possible (for example,
due to excessive windmilling eects), then a
brake resistor is recommended.
NOTICE!
The frequency converter must be equipped with a break
chopper.
When possible, the control unit may attempt to correct the
ramp (parameter 2-17 Over-voltage Control).
The inverter turns o when a certain voltage level is
reached, to protect the transistors and the DC link
capacitors.
See parameter 2-10 Brake Function and parameter 2-17 Over-voltage Control to select the method used for controlling
the DC-link voltage level.
NOTICE!
OVC cannot be activated when running a PM motor, that
is, for parameter 1-10 Motor Construction set to [1] PMnon-salient SPM.
Mains drop-out
During mains drop-out, the frequency converter keeps
running until the DC-link voltage drops below the
minimum stop level. The minimum stop level is typically
15% below the lowest rated supply voltage of the
frequency converter. The mains voltage before the dropout, combined with the motor load, determines how long
it takes for the inverter to coast.
Static overload in VVC+ mode
When the frequency converter is overloaded, the controls
reduce the output frequency to reduce the load. Overload
is dened as reaching the torque limit set in
For extreme overload, a current acts to ensure the
frequency converter cuts out after approximately 5–
10 seconds.
Operation within the torque limit is limited in time (0–
60 seconds) in parameter 14-25 Trip Delay at Torque Limit.
3.4.4.1 Motor Thermal Protection
To protect the application from serious damage, the
frequency converter oers several dedicated features:
Torque limit
The torque limit feature protects the motor from being
overloaded independent of the speed. Select torque limit
settings in parameter 4-16 Torque Limit Motor Mode and/orparameter 4-17 Torque Limit Generator Mode. Set the time
to trip for the torque limit warning in parameter 14-25 TripDelay at Torque Limit.
Current limit
Set the current limit in parameter 4-18 Current Limit. Set the
time before the current limit warning trips in
parameter 14-24 Trip Delay at Current Limit.
Minimum speed limit
Parameter 4-11 Motor Speed Low Limit [RPM] or
parameter 4-12 Motor Speed Low Limit [Hz] limit the
operating speed range to for instance between 30 and
50/60 Hz. Maximum speed limit: Parameter 4-13 Motor
Speed High Limit [RPM] or parameter 4-19 Max Output
Frequency limit the maximum output speed the frequency
converter can provide.
ETR (electronic thermal relay)
The ETR function measures actual current, speed, and time
to calculate motor temperature and protect the motor
from being overheated (warning or trip). An external
thermistor input is also available. ETR is an electronic
feature that simulates a bimetal relay based on internal
measurements. The characteristic is shown in Figure 3.12.
Figure 3.12 ETR Functions
In Figure 3.12 the X-axis shows the ratio between I
I
nominal. The Y-axis shows the time in seconds before
motor
the ETR cut of and trips the frequency converter. The
curves show the characteristic nominal speed, at twice the
nominal speed and at 0.2 x the nominal speed.
At lower speed the ETR cuts o at lower heat due to less
cooling of the motor. In that way, the motor is protected
from overheating even at low speed. The ETR feature
calculates the motor temperature based on actual current
and speed. The calculated temperature is visible as a
readout parameter in parameter 16-18 Motor Thermal in the
frequency converter.
Final Test and Set-up
3.5
motor
and
WARNING
HIGH LEAKAGE CURRENT
When running high-voltage tests of the entire installation, leakage currents can be high. Failure to follow
recommendations could result in death or serious injury.
Interrupt the mains and motor connection if the
•
leakage currents are too high.
3.5.2 Grounding
The following basic issues need to be considered when
installing a frequency converter to obtain electromagnetic compatibility (EMC).
Safety grounding: Note that the frequency
•
converter has a high leakage current and must be
grounded appropriately for safety reasons. Apply
local safety regulations.
High frequency grounding: Keep the ground wire
•
connections as short as possible.
Connect the dierent ground systems at the lowest
possible conductor impedance. The lowest possible
conductor impedance is obtained by keeping the
conductor as short as possible and by using the greatest
possible surface area.
The metal cabinets of the dierent devices are mounted
on the cabinet rear plate using the lowest possible HF
impedance. This avoids having dierent HF voltages for the
individual devices and avoids the risk of radio interference
currents running in connection cables that may be used
between the devices. The radio interference has been
reduced.
To obtain a low HF impedance, use the fastening bolts of
the devices as HF connection to the rear plate. It is
necessary to remove insulating paint or similar from the
fastening points.
3.5.3 Safety Grounding Connection
The frequency converter has a high leakage current and
must be grounded appropriately for safety reasons
according to IEC 61800-5-1.
33
3.5.1 High-voltage Test
Carry out a high-voltage test by short-circuiting terminals
U, V, W, L1, L2, and L3. Energize maximum 2.15 kV DC for
380–500 V frequency converters for 1 s between this short
circuit and the chassis.
The VLT® Decentral Drive FCD 302 features a mechanical brake control designed for hoisting applications. The hoist
mechanical brake is activated via option [6] Hoist Mech. Brake Rel in parameter 1-72 Start Function. The main dierence
compared to the regular mechanical brake control, where a relay function monitoring the output current is used, is that the
hoist mechanical brake function has direct control over the brake relay. This means that instead of setting a current for
release of the brake, the torque is applied against the closed brake before release is dened. Because the torque is dened
directly, the set-up is more straightforward for hoisting applications.
Set parameter 2-28 Gain Boost Factor to obtain a quicker control when releasing the brake. The hoist mechanical brake
strategy is based on a 3-step sequence, where motor control and brake release are synchronized to obtain the smoothest
possible brake release.
44
3-step sequence
1.Pre-magnetize the motor
To ensure that there is a hold on the motor and to verify that it is mounted correctly, the motor is rst premagnetized.
2.Apply torque against the closed brake
When the load is held by the mechanical brake, its size cannot be determined, only its direction. The moment the
brake opens, the load must be taken over by the motor. To facilitate the takeover, a user-dened torque, set in
parameter 2-26 Torque Ref, is applied in hoisting direction. This is used to restore the speed controller that nally
takes over the load. To reduce wear on the gearbox due to backlash, the torque is acceled.
3.Release brake
When the torque reaches the value set in parameter 2-26 Torque Ref, the brake is released. The value set in
parameter 2-25 Brake Release Time determines the delay before the load is released. To react as quickly as possible
on the load-step that follows brake release, increase the proportional gain to boost the speed PID control.
The purpose of this guideline is to ease the set-up of
encoder connection to the frequency converter. Before
setting up the encoder, the basic settings for a closed-loop
speed control system is shown.
Figure 4.6 Encoder Connection to the Frequency Converter
4.7.1 Encoder Direction
The direction of the encoder is determined by which order
the pulses are entering the frequency converter.
Clockwise direction means channel A is 90
•
electrical degrees before channel B.
Counterclockwise direction means channel B is 90
•
electrical degrees before A.
The direction is determined by looking into the shaft end.
4.8 Closed-loop Drive System
A closed-loop drive system usually comprises elements
such as:
Motor.
•
Additional equipment:
•
-Gearbox
-Mechanical Brake
Frequency converter.
•
Encoder as feedback system.
•
Brake resistor for dynamic brake.
•
Transmission.
•
Load.
•
Applications demanding mechanical brake control usually
needs a brake resistor.
44
Figure 4.7 24 V Incremental Encoder with Maximum Cable
Coast
Start timer
Set Do X low
Select set-up 2
. . .
Running
Warning
Torque limit
Digital input X 30/2
. . .
=
TRUE longer than..
. . .
. . .
Par. 13-11
Comparator Operator
=
TRUE longer than.
. . .
. . .
Par. 13-10
Comparator Operand
Par. 13-12
Comparator Value
130BB672.10
. . .
. . .
. . .
. . .
Par. 13-43
Logic Rule Operator 2
Par. 13-41
Logic Rule Operator 1
Par. 13-40
Logic Rule Boolean 1
Par. 13-42
Logic Rule Boolean 2
Par. 13-44
Logic Rule Boolean 3
130BB673.10
Application ExamplesDesign Guide
4.9 Smart Logic Control
Smart logic control (SLC) is essentially a sequence of user-dened actions (see parameter 13-52 SL Controller Action
[x]) executed by the SLC when the associated user-dened
event (see parameter 13-51 SL Controller Event [x]) is
evaluated as true by the SLC.
The condition for an event can be a particular status or
that the output from a logic rule or a comparator operand
becomes true. This leads to an associated action as
illustrated in Figure 4.9.
44
Figure 4.10 Example - Internal Current Control
Comparators
Comparators are used for comparing continuous variables
(that is, output frequency, output current, analog input,
and so forth) to xed preset values.
Events and actions are each numbered and linked together
in pairs (states). This means that when event [0] is fullled
(attains the value true), action [0] is executed. After this,
the conditions of event [1] is evaluated and if evaluated
true, action [1] is executed, and so on. Only 1 event is
evaluated at any time. If an event is evaluated as false,
nothing happens (in the SLC) during the current scan
interval and no other events are evaluated. This means
that when the SLC starts, it evaluates event [0] (and only
event [0]) each scan interval. Only when event [0] is
evaluated true, the SLC executes action [0] and starts
evaluating event. It is possible to program from 1 to 20
events and actions.
When the last event/action has been executed, the
sequence starts over again from event [0]/action [0].
Figure 4.10 shows an example with 3 event/actions.
Figure 4.9 Current Control Status/Event and Action
Figure 4.11 Comparators
Logic rules
Combine up to 3 boolean inputs (true/false inputs) from
timers, comparators, digital inputs, status bits, and events
using the logical operators AND, OR, and NOT.
Under some special conditions, where the operation of the
frequency converter is challenged, consider derating. In
some conditions, derating must be done manually.
In other conditions, the frequency converter automatically
performs a degree of derating when necessary. This is
done to ensure the performance at critical stages where
the alternative could be a trip.
5.1 Manual Derating
Manual derating must be considered for:
Air pressure – relevant for installation at altitudes
•
above 1000 m (3280 ft)
Motor speed – at continuous operation at low
•
RPM in constant torque applications
Ambient temperature – relevant for ambient
•
temperatures above 40 °C (104 °F)
Contact Danfoss for the application note for tables and
elaboration. Only the case of running at low motor speeds
is elaborated here.
5.1.1 Derating for Low Air Pressure
The cooling capability of air is decreased at lower air
pressure.
Below 1000 m (3280 ft) altitude no derating is necessary.
But above 1000 m (3280 ft) the ambient temperature
(T
) or maximum output current (I
AMB
in accordance with the diagram in Figure 5.1.
) should be derated
out
An alternative is to lower the ambient temperature at high
altitudes and by that ensuring 100% output current at high
altitudes. As an example of how to read the graph, the
situation at 2000 m (6561 ft) is elaborated for a 3 kW
(4 hp) frequency converter with T
At a temperature of 36 °C (96.8 °F) (T
= 40 °C (104 °F).
AMB, MAX
AMB, MAX
- 3.3 K), 91%
of the rated output current is available. At a temperature
of 41.7 °C (107 °F), 100% of the rated output current is
available.
5.1.2 Derating for Running at Low Speed
When a motor is connected to a frequency converter, it is
necessary to check that the cooling of the motor is
adequate.
The level of heating depends on the load on the motor,
and the operating speed and time.
Constant torque applications (CT mode)
A problem may occur at low RPM values in constant
torque applications. In a constant torque application, a
motor may overheat at low speed due to less cooling air
from the motor integral fan.
Therefore, if the motor is to be run continuously at an RPM
value lower than half of the rated value, the motor must
be supplied with extra air-cooling (or a motor designed for
this type of operation may be used).
An alternative is to reduce the load level of the motor by
selecting a larger motor. However, the design of the
frequency converter puts a limit to the motor size.
Variable (quadratic) torque applications (VT)
In VT applications such as centrifugal pumps and fans,
where the torque is proportional to the square of the
speed and the power is proportional to the cube of the
speed, there is no need for extra cooling or derating of the
motor.
55
AMB,
Figure 5.1 Derating of output current versus altitude at T
for VLT® Decentral Drive FCD 302. At altitudes above
Graphs are presented individually for 60° AVM and SFAVM.
5.1.3.2 Power Size 1.1–1.5 kW
60° AVM - Pulse width modulation
60° AVM only switches 2/3 of the time whereas SFAVM
switches throughout the whole period. The maximum
switching frequency is 16 kHz for 60° AVM and 10 kHz for
SFAVM. The discrete switching frequencies are presented in
Table 5.1.
Switchin
55
g
pattern
60° AVM
2 2.5 3 3.545678 10 12 14 16
SFAVM2 2.5 33.545678 10 –––
Table 5.1 Discrete Switching Frequencies
5.1.3.1 Power Size 0.37–0.75 kW
Discrete switching frequencies
Figure 5.4 Derating of I
for dierent T
out
AMB, MAX
for FCD 302
1.1–1.5 kW, using 60° AVM
SFAVM - Stator frequency asynchron vector modulation
60° AVM - Pulse width modulation
Figure 5.2 Derating of I
for dierent T
out
AMB, MAX
for FCD 302
0.37–0.55–0.75 kW, using 60° AVM
SFAVM - Stator frequency asynchron vector modulation
The frequency converter constantly checks for critical levels:
Critical high temperature on the control card or heat sink
•
High motor load
•
High DC-link voltage
•
Low motor speed
•
SFAVM - Stator frequency asynchron vector modulation
Figure 5.7 Derating of I
2.2–3.0 kW, using SFAVM
for dierent T
out
AMB, MAX
for FCD 302
55
As a response to a critical level, the frequency converter adjusts the switching frequency. For critical high internal temperatures and low motor speed, the frequency converter can also force the PWM pattern to SFAVM.
NOTICE!
The automatic derating is dierent when parameter 14-55 Output Filter is set to [2] Sine-Wave Filter Fixed.
The automatic derating is made up of contributions from separate functions that evaluate the need. Their interrelationship is
illustrated in Figure 5.9.
In sine-wave lterxed mode, the structure is dierent. See chapter 5.2.1 Sine-Wave Filter Fixed Mode.
55
Figure 5.8 Automatic Derating Function Block
Figure 5.9 Interrelationship Between the Automatic Derating Contributions
The switching frequency is rst derated due to motor current, followed by DC-link voltage, motor frequency, and then
temperature. If multiple deratings occur on the same iteration, the resulting switching frequency would be the same as
though only the most signicant derating occurred by itself (the deratings are not cumulative). Each of these functions is
presented in the following sections.
If the frequency converter is running with a xed frequency sine-wave lter, the switching frequency is not derated due to
motor current or DC-link voltage. The switching frequency is still derated due to motor frequency and temperature; however
the order of these 2 operations is reversed. It should be noted that, in this situation, the function for derating based on
motor frequency does nothing unless the frequency converter’s LC_Low_Speed_Derate_Enable PUD parameter is set to true.
Also, the function for derating due to temperature is slightly dierent. In sine lterxed mode, a dierent protection mode
switching frequency is sent to the DSP.
55
Figure 5.10 The Switching Frequency Limiting Algorithm when the Frequency Converter is Operating with a Fixed Frequency Sine-
Background for derating PWM - Functions that adjust the switching
fsw – Functions that derate the switching frequency
pattern
I
↑
load
55
Udc ↑
f
s
No automatic derating
No automatic derating
T ↑
Table 5.2 Overview - Derating
5.2.3 High Motor Load
The switching frequency is automatically adjusted
according to the motor current.
When a certain percentage of the nominal HO motor load
is reached, the switching frequency is derated. This
percentage is individual for each enclosure size and a value
that is coded in the EEPROM along with the other points
that limit the derating.
Figure 5.11 Derating of Switching Frequency According to
Motor Load. f1, f2, I1, and I2 are Coded in EEPROM.
In EEPROM, the limits depend on the modulation mode. In
60° AVM, f1 and f2 are higher than for SFAVM. I1 and I2 are
independent of modulation mode.
fsw [kHz]
Udc [V ]
U2
U1
f1
f2
130BB978.10
PWM
fm[Hz]
SFAVM
60PWM
optional
fm,switch2fm,switch1
130BB979.10
fm [HZ]
fsw [kHz]
fm4
SFAVM only
fm5 (fm, switch 1)fm1 fm2fm3
f
sw,fm2
,
f
sw,fm3
f
sw,fm 4
f
sw,fm1
Is< K
Is1*Inom ,ho
K
Is1*Inom,ho
<= Is< K
Is2*Inom,ho
Is>= K
Is2*Inom,ho
130BB980.10
Special ConditionsDesign Guide
5.2.4 High Voltage on the DC link
The switching frequency is automatically adjusted
according to the voltage on the DC link.
When the DC link reaches a certain magnitude, the
switching frequency is derated. The points that limit the
derating are individual for each enclosure size and are
coded in the EEPROM.
Figure 5.12 Derating of Switching Frequency According to
Voltage on the DC link. f1, f2, U1, and U2 are Coded in
EEPROM.
In EEPROM the limits depend on the modulation mode. In
60° AVM, f1 and f2 are higher than for SFAVM. U1 and U2
are independent of the modulation mode.
5.2.5 Low Motor Speed
is used. Therefore, for low values of the stator frequency
where the temperature variations are large, the switching
frequency can be reduced to lower the peak temperature
and thereby the temperature variations.
For VT-applications, the load current is relatively small for
small stator frequencies and the temperature variations are
thus not as large as for the CT-applications. For this reason,
also the load current is considered.
55
Figure 5.14 Switching Frequency (fsw) Variation for Dierent
Stator Frequencies (fm)
The points that limit the derating are individual for each
enclosure size and are coded in the EEPROM.
The option of PWM strategy depends on the stator
frequency. To prevent that the same IGBT is conducting for
too long (thermal consideration), fm, switch1 is specied as
the minimum stator frequency for 60° PWM, whereas fm,
NOTICE!
The VLT® Decentral Drive FCD 302 never derates the
current automatically. Automatic derating refers to
adaptation of the switching frequency and pattern.
switch2 is specied as the maximum stator frequency for
SFAVM to protect the frequency converter. 60° PWM helps
to reduce the inverter loss above f
m, switch1
as the switch
For VT-applications, the load current is considered before
derating the switching frequency at low motor speed.
loss is reduced by 1/3 by changing from SFAVM to
60° AVM.
5.2.6 High Internal
The switching frequency is derated based on both control
card- and heat sink temperature. This function may
sometimes be referred to as the temperature adaptive
switching frequency function (TAS).
Figure 5.13 Reducing Inverter Loss
The shape of the average temperature is constant
regardless of the stator frequency. The peak temperature,
however, follows the shape of the output power for small
stator frequencies and goes towards the average
temperature for increasing stator frequency. This results in
higher temperature variations for small stator frequencies.
This means that the expected lifetime of the component
decreases for small stator frequencies if no compensation
Figure 5.15 shows 1 temperature aecting the derating.
In fact there are 2 limiting temperatures: Control card
temperature and heat sink temperature. Both have their
own set of control temperatures.
VLT® Decentral Drive FCD 302
Derating for Running at Low Speed
5.3
When a motor is connected to a frequency converter, it is
necessary to check that the cooling of the motor is
adequate.
The level of heating depends on the load on the motor,
the operating speed, and time.
Constant torque applications (CT mode)
A problem may occur at low RPM values in constant
55
torque applications. In constant torque applications, a
motor may overheat at low speeds due to less cooling air
from the motor integral fan. Therefore, if the motor is to
be run continuously at an RPM value lower than half of the
rated value, the motor must be supplied with extra aircooling (or a motor designed for this type of operation
may be used). An alternative is to reduce the load level of
the motor by selecting a larger motor. However, the design
Figure 5.15 Switching Frequency Derating due to High
Temperature
of the frequency converter puts a limit to the motor size.
Variable (quadratic) torque applications (VT)
In VT applications such as centrifugal pumps and fans, the
torque is proportional to the square of the speed and the
NOTICE!
dt is 10 s when the control card is too hot but 0 s when
the heat sink is too hot (more critical).
power is proportional to the cube of the speed. In these
applications, there is no need for extra cooling or derating
of the motor. In Figure 5.16, the typical VT curve is below
the maximum torque with derating and maximum torque
The high warning can only be violated for a certain time
with forced cooling at all speeds.
before the frequency converter trips.
5.2.7 Current
The nal derating function is a derating of the output
current due to high temperatures. This calculation takes
place after the calculations for derating the switching
frequency. This results in an attempt to lower the temperatures by rst lowering the switching frequency, and then
lowering the output current. Current derating is only
performed if the unit is programmed to derate in overtemperature situations. If the user has selected a trip function
for overtemperature situations, the current derate factor is
not lowered.
Figure 5.16 VT Applications - Maximum Load for a Standard
Motor at 40 °C (104 °F)
NOTICE!
Oversynchronous speed operation results in decrease of
the available motor torque, inversely proportional to the
increase in speed. Consider this during the design phase
to avoid motor overload.
FDirect mount 6xM12: 4 digital inputs, 2 relay outputs
XNo eldbus plug
EM12 Ethernet
PM12 PROFIBUS
AXNo A option
A0PROFIBUS DP
ANEtherNet/IP
ALPROFINET
BXNo B option
BREncoder option
BUResolver option
BZSafety PLC Interface
DXNo D option
D024 V DC back-up input
Figure 6.1 Type Code Description
Not all choices/options are available for each VLT® Decentral Drive FCD 302 variant. To verify if the appropriate version is
available, consult the Drive Congurator on the Internet: vltcong.danfoss.com/ .
NOTICE!
A and D options for FCD 302 are integrated into the control card. Do not use pluggable options for frequency
converters. Future retrot requires exchange of the entire control card. B options are pluggable, using the same concept
as for frequency converters.
6.2 Ordering Numbers
6.2.1 Ordering Numbers: Accessories
AccessoriesDescriptionOrdering number
Mounting brackets extended40 mm brackets130B5771
Mounting bracketsFlat brackets130B5772
LCP cablePreconfectioned cable to be used between inverter and LCP130B5776
Danfoss oers a wide range of options and accessories for
the frequency converter.
6.3.1 Fieldbus Options
Select the eldbus option when ordering the frequency
converter. All eldbus options are included on the control
card. No separate A option is available.
To change the eldbus option later, change out the control
card. The following control cards with dierent eldbus
options are available. All control cards have 24 V back-up
as standard.
ItemOrdering number
Control card PROFIBUS130B5781
Control card Ethernet130B5788
Control card PROFINET130B5794
Table 6.3 Control Cards with Fieldbus Options
6.3.2
VLT® Encoder Input MCB 102
The encoder module can be used as feedback source for
closed-loop ux control (parameter 1-02 Flux MotorFeedback Source) and closed-loop speed control
(parameter 7-00 Speed PID Feedback Source). Congure the
encoder option in parameter group 17-** Position Feedback.
Flux vector torque control.
•
Permanent magnet motor.
•
Supported encoder types:
Incremental encoder: 5 V TTL type, RS422,
•
maximum frequency: 410 kHz
Incremental encoder: 1Vpp, sine-cosine
•
Hiperface® Encoder: Absolute and Sine-Cosine
•
(Stegmann/SICK)
EnDat encoder: Absolute and Sine-Cosine
•
(Heidenhain) Supports version 2.1
SSI encoder: Absolute
•
Encoder monitor: The 4 encoder channels (A, B, Z,
•
and D) are monitored, open, and short circuit can
be detected. There is a green LED for each
channel which lights up when the channel is OK.
NOTICE!
The LEDs are not visible when mounted in a VLT
Decentral Drive FCD 302 frequency converter. Reaction in
case of an encoder error can be selected in
parameter 17-61 Feedback Signal Monitoring: [0] Disabled,
[1] Warning, or [2] Trip.
The MCB 103 is used for interfacing resolver motor
feedback to the frequency converter. Resolvers are used
basically as motor feedback device for permanent magnet
brushless synchronous motors.
Figure 6.5 Connections for Resolver Option MCB 103
The resolver option kit comprises:
MCB 103 Resolver Option.
•
Cable to connect customer terminals to control
•
card.
Find the relevant parameters in parameter group 17-5*Resolver Interface.
MCB 103 supports a various number of resolver types.
Resolver polesParameter 17-50 Poles: 2 *2
Resolver input
voltage
Resolver input
frequency
Transformation ratio Parameter 17-53 Transformation Ratio: 0.1–
Secondary input
voltage
Secondary load
Parameter 17-51 Input Voltage: 2.0–8.0 V
*7.0 V
rms
Parameter 17-52 Input Frequency: 2–15 kHz
*10.0 kHz
1.1 *0.5
Maximum 4 V
Approximately 10 kΩ
Table 6.5 Resolver Option MCB 103 Specications
rms
rms
NOTICE!
The Resolver Option MCB 103 can only be used with
rotor-supplied resolver types. Stator-supplied resolvers
cannot be used.
NOTICE!
LED indicators are not visible at the resolver option.
A 24 V DC external supply can be installed for low voltage supply to the control card and any option card installed. This
enables full operation of the LCP (including the parameter setting) without connection to mains.
VLT® Decentral Drive FCD 302
6
24 V DC external supply
Input voltage range24 V DC ±15% (maximum 37 V in 10 s)
Maximum input current2.2 A
Average input current0.9 A
Maximum cable length75 m
Input capacitance load<10 uF
Power-up delay<0.6 s
The inputs are protected.