Danfoss VLT Micro Drive FC 51 Design Manual

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Design Guide

VLT® Micro Drive FC 51

Contents

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Contents

VLT® Micro Drive FC 51 Design Guide

1 How to Read this Design Guide

1.1.1 Legal Information 5

1.1.2 Available Literature 6

1.1.3 Symbols 6

1.1.4 Abbreviations 6

1.1.5 Definitions 7

2 Safety and Conformity

2.1 Safety

2.1.2 Safety 10

2.2 CE Labeling

2.3 Aggressive Environments

2.4 Vibration and Shock

3 Introduction to VLT® Micro Drive

3.1 Control Structures

3.2 General Aspects of EMC

3.3 Galvanic Isolation (PELV)

5

10
10

11
12
13

18
18
21
23

3.4 Earth Leakage Current

3.5 Extreme Running Conditions

4 VLT® Micro Drive Selection

4.1 Options and Accessories

4.1.1 Local Control Panel (LCP) 26

4.1.2 FC 51 Mounting Instruction 27

4.1.3 FC 51 Remote Mounting Kit Mounting Instruction 28

4.1.4 IP21/TYPE 1 Enclosure Kit 30

4.1.5 Type 1 (NEMA) 30

4.1.6 De-Coupling 30

4.1.7 FC 51 Type 1 Kit Mounting Instruction for M1, M2 and M3 31

4.1.8 FC 51 Type 1 Kit Mounting Instruction for M4 and M5 32

4.1.9 FC 51 IP21 Kit Mounting Instruction 33

4.1.10 FC 51 De-coupling Plate Mounting Instruction for M1 and M2 35

4.1.11 FC 51 De-coupling Plate Mounting Instruction for M3 36

4.1.12 FC 51 De-coupling Plate Mounting Instruction for M4 and M5 37

4.1.13 FC 51 DIN Rail Kit Mounting Instruction 38

24
24

26
26

4.1.14 Line Filter MCC 107 Installation Instructions 38

4.1.15 Mounting 39

4.1.16 Wiring 39

4.1.17 Dimensions 40

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1

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4.2 Special Conditions

4.2.1 Purpose of Derating 41

4.2.2 Derating for Ambient Temperature 41

4.2.3 Derating for Low Air Pressure 42

4.2.5 Derating for Running at Low Speed 42

5 How to Order

5.1 Drive Configurator

5.2.1 FC Identification 43

5.3.1 Type Code 44

5.4.1 Ordering Numbers 45

5.5.1 Options for VLT Micro Drive 45

6 How to Install

6.1 Before Starting

6.2 Side-by-Side Installation

6.3 Before Commencing Repair Work

6.4 Mechanical Dimensions

41

43
43

47
47
47
47
48

6.5 Electrical Installation in General

6.6 Fuses

6.7 Mains Connection

6.8 Motor Connection

6.9.1 Use of EMC-Correct Cables 54

6.12 Electrical Overview

6.12.1 Power Circuit - Overview 56

6.13 Electrical Installation and Control Cables

6.14 Control Terminals

6.14.2 Connecting to Control Terminals 58

6.15 Switches

6.16 Final Set-Up and Test

6.17 Parallel Connection of Motors

6.18 Motor Installation

6.19 Installation of Misc. Connections

6.20 Safety

6.20.1 High Voltage Test 62

49
50
51
51

56

57
57

58
58
60
61
61
62

6.20.2 Safety Earth Connection 62

7 Programming

7.1 How to Programme

7.1.1 Programming with MCT 10 Set-up Software 63

7.1.2 Programming with the LCP 11 or LCP 12 63

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63
63

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7.2 Status Menu

7.3 Quick Menu

7.4 Quick Menu Parameters

7.5 Main Menu

7.6 Quick Transfer of Parameter Settings between Multiple Frequency Converters

7.7 Read-out and Programming of Indexed Parameters

7.8 Initialise the Frequency Converter to Default Settings in two Ways

7.8.1 Initialise the Frequency Converter to Default Settings in two Ways 69

8 RS-485 Installation and Set-up

8.1.1 Overview 70

8.1.4 EMC Precautions 71

8.2 FC Protocol Overview

8.3 Network Configuration

8.4 FC Protocol Message Framing Structure

8.4.1 Content of a Character (byte) 72

8.4.2 Telegram Structure 72

8.4.3 Telegram Length (LGE) 72

64
64
65
68
68
68
69

70

71
72
72

8.4.6 The Data Field 73

8.4.13 Process Words (PCD) 75

8.5 Examples

8.6 Modbus RTU Overview

8.6.1 Assumptions 76

8.6.2 What the User Should Already Know 76

8.6.3 Modbus RTU Overview 76

8.6.4 Frequency Converter with Modbus RTU 77

8.8 Modbus RTU Message Framing Structure

8.8.1 Frequency Converter with Modbus RTU 77

8.8.2 Modbus RTU Message Structure 77

8.8.3 Start/Stop Field 78

8.8.4 Address Field 78

8.8.5 Function Field 78

8.8.6 Data Field 78

8.8.7 CRC Check Field 78

8.8.9 How to Control the Frequency Converter 80

75
76

77

8.8.10 Function Codes Supported by Modbus RTU 80

8.8.11 Modbus Exception Codes 80

8.9 How to Access Parameters

8.9.1 Parameter Handling 81

8.9.2 Storage of Data 81

8.9.3 IND 81

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81

3

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8.9.4 Text Blocks 81

8.9.5 Conversion Factor 81

8.9.6 Parameter Values 81

8.10 Examples

8.10.2 Force/Write Single Coil (05 HEX) 82

8.10.3 Force/Write Multiple Coils (0F HEX) 82

8.10.5 Preset Single Register (06 HEX) 83

8.11 FC Drive Control Profile

8.11.1 Control Word According to FC Profile (8-10 Protocol = FC profile) 84

9 Specifications

Index

81

84

89

94

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VLT® Micro Drive FC 51 Design Guide

1 How to Read this Design Guide

VLT®

Software version: 2.7X

Table 1.1

This guide can be used with all

VLT® Micro Drive frequency

converters with software version

The actual software version

Micro Drive

FC 51 Series

2.7X.

1.1.1 Legal Information

This publication contains information proprietary to
Danfoss.
agrees that the information contained herein is used solely
for operating equipment from Danfoss or equipment from
other vendors if such equipment is intended for communi­cation with Danfoss equipment over a serial
communication link. This publication is protected under
the Copyright laws of Denmark and most other countries.

Danfoss does not warrant that a software program
produced according to the guidelines provided in this
manual functions properly in every physical, hardware or
software environment.

Although Danfoss has tested and reviewed the documen­tation within this manual, Danfoss makes no warranty or
representation, neither expressed nor implied, with respect
to this documentation, including its quality, performance,
or fitness for a particular purpose.

By accepting and using this manual the user

1 1

number can be read from

15-43 Software Version.

Table 1.2

In no event shall Danfoss be liable for direct, indirect,
special, incidental, or consequential damages arising out of
the use, or the inability to use information contained in
this manual, even if advised of the possibility of such
damages. In particular, Danfoss is not responsible for any
costs, including but not limited to those incurred as a
result of lost profits or revenue, loss or damage of
equipment, loss of computer programs, loss of data, the
costs to substitute these, or any claims by third parties.

Danfoss reserves the right to revise this publication at any
time and to make changes to its contents without prior
notice or any obligation to notify former or present users
of such revisions or changes.

MG02K202 - VLT® is a registered Danfoss trademark

5

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VLT® Micro Drive FC 51 Design Guide

11

1.1.2 Available Literature

NOTE

This design guide contains the basic information necessary
for installing and running the frequency converter.

Danfoss technical literature is available in print from local
Danfoss Sales Offices or online at: Danfoss

website /

BusinessAreas/DrivesSolutions/Documentations

-

VLT Micro Drive FC 51 Quick Guide, MG02B

-

VLT Micro Drive FC 51 Programming Guide, MG02C

-

FC 51 LCP Mounting Instruction, MI02A

-

FC 51 De-coupling Plate Mounting Instruction,
MI02B

-

FC 51 Remote Mounting Kit Mounting Instruction,
MI02C

-

FC 51 DIN Rail Kit Mounting Instruction, MI02D

-

FC 51 IP21 Kit Mounting Instruction, MI02E

-

FC 51 Nema1 Kit Mounting Instruction, MI02F

-

FC 51 Line Filter MCC 107 Installation Instruction,
MI02U

1.1.3 Symbols

The following symbols are used in this manual.

WARNING

Indicates a potentially hazardous situation which, if not
avoided, could result in death or serious injury.

CAUTION

Indicates a potentially hazardous situation which, if not
avoided, may result in minor or moderate injury. It may
also be used to alert against unsafe practices.

CAUTION

Indicates a situation
property-damage-only accidents.

that may result in equipment or

1.1.4 Abbreviations

Alternating current AC
American wire gauge AWG
Ampere/AMP A
Automatic Motor Tuning AMT
Current limit I
Degrees Celsius

current DC

Direct
Electro Magnetic Compatibility EMC
Electronic Thermal Relay ETR
Frequency Converter FC
Gram g
Hertz Hz
Kilohertz kHz
Local Control Panel
Meter m
Millihenry Inductance mH
Milliampere mA
Millisecond ms
Minute min
Motion Control Tool MCT
Nanofarad nF
Newton Meters Nm
Nominal motor current I
Nominal motor frequency f
Nominal motor power P
Nominal motor voltage U
Protective Extra Low Voltage PELV
Printed Circuit Board PCB
Rated Inverter Output Current I
Revolutions Per Minute RPM
Regenerative terminals Regen
Second s
Synchronous Motor Speed n
Torque limit T
Volts V
The maximum output current I
The rated output current supplied by the
frequency

Table 1.3

converter

LIM

°

C

M,N

M,N

M,N

M,N

INV

s

LIM

VLT,MAX

I

VLT,N

NOTE

Indicates highlighted information that should be regarded
with attention to avoid mistakes or operate equipment at
less than optimal performance.

6 MG02K202 - VLT® is a registered Danfoss trademark

175ZA078.10

Pull-out

rpm

Torque

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VLT® Micro Drive FC 51 Design Guide

1.1.5 Definitions

I

VLT,MAX

The maximum output current.

I

VLT,N

The rated output current supplied by the frequency
converter.

U

VLT, MAX

The maximum output voltage.

Input

Control command
The connected motor can
be started and stopped with
LCP and the digital inputs.
Functions are divided into 2
groups.
Functions in group 1 have
higher priority than
functions in group 2.

Group1Reset, Coasting stop,

Reset and Coasting stop,
Quick-stop, DC braking,
Stop and the [Off] key.

Group2Start, Pulse start,

Reversing, Start reversing,
Jog and Freeze output

P

M,N

The rated motor power (nameplate data).

U

M

The instantaneous motor voltage.

U

M,N

The rated motor voltage (nameplate data).

Break-away torque

1 1

Table 1.4

Motor

f

JOG

The motor frequency when the jog function is activated
(via digital terminals).

f

M

The motor frequency.

f

MAX

The maximum motor frequency.

f

MIN

The minimum motor frequency.

f

M,N

The rated motor frequency (nameplate data).

I

M

The motor current.

I

M,N

The rated motor current (nameplate data).

n

M,N

The rated motor speed (nameplate data).

Illustration 1.1

η

VLT

The efficiency of the is defined as the ratio between the
power output and the power input.

Start-disable command
A stop command belonging to the group 1 control
commands - see this group.

Stop command
See Control commands.

References

Analog Reference
A signal transmitted to the analog inputs 53 or 54, can be
voltage or current.

Bus Reference
A signal transmitted to the serial communication port (FC
port).

Preset Reference
A defined preset reference to be set from -100% to +100%
of the reference range. Selection of eight preset references
via the digital terminals.

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11

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 set in
3-03 Maximum Reference.

Ref

MIN

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 set in

3-02 Minimum Reference

Miscellaneous
Analog Inputs
The analog inputs are used for controlling various
functions of the frequency converter.
There are two types of analog inputs:
Current input, 0-20 mA and 4-20 mA
Voltage input, 0-10 V DC.

Analog Outputs
The analog outputs can supply a signal of 0-20 mA, 4-20
mA, or a digital signal.

Automatic Motor Tuning, AMT
AMT 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 braking power increases the intermediate
circuit 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.

Relay Outputs
The features two programmable Relay Outputs.

ETR
Electronic Thermal Relay is a thermal load calculation
based on present load and time. Its purpose is to estimate
the motor temperature.

Initialising
If initialising is carried out (14-22 Operation Mode
programmable parameters of the frequency converter
return to their default settings.
Initialising; 14-22 Operation Mode will not initialise
communication parameters.

Intermittent Duty Cycle
An intermittent duty rating refers to a sequence of duty
cycles. Each cycle consists of an on-load and an off-load
period. The operation can be either periodic duty or none­periodic duty.

), the

LCP
The Local Control Panel (LCP) 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 from the frequency converter, that is,
in a front panel with the installation kit option.

lsb
Least significant bit.

MCM
Short for Mille Circular Mil, an American measuring unit for
cable cross-section. 1 MCM ≡ 0.5067 mm2.

msb
Most significant bit.

On-line/Off-line Parameters
Changes to on-line parameters are activated immediately
after the data value is changed. Changes to off-line
parameters are not activated until you enter [OK] on the
LCP.

PI Controller
The PI controller maintains the desired speed, pressure,
temperature, etc. by adjusting the output frequency to
match the varying load.

RCD
Residual Current Device.

Set-up
You can save parameter settings in 2 Set-ups. Change
between the 2 parameter Set-ups and edit one Set-up,
while another Set-up is active.

Slip Compensation
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.

Smart Logic Control (SLC)
The SLC is a sequence of user-defined actions executed
when the associated user-defined events are evaluated as
true by the SLC.

Thermistor
A temperature-dependent resistor placed where the
temperature is to be monitored (frequency converter or
motor).

STW
Status Word.

FC Standard Bus
Includes RS 485 bus with FC protocol. See 8-30 Protocol.

Trip
A state entered in fault situations, e.g. if the frequency
converter is subject to an over-temperature or when the
frequency converter is protecting the motor, process or
mechanism. Restart is prevented until the cause of the
fault has disappeared and the trip state is canceled by
activating reset or, in some cases, by being programmed

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to reset automatically. Trip may not be used for personal
safety.

Trip Locked
A state entered in fault situations when the frequency
converter is protecting itself and requiring physical
intervention, for example, if the frequency converter is
subject to a short circuit on the output. A locked trip can
only be canceled by cutting off 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, in some cases, by being programmed
to reset automatically. Trip locked may not be used for
personal safety.

VT Characteristics
Variable torque characteristics used for pumps and fans.

plus

VVC
If compared with standard voltage/frequency ratio control,
Voltage Vector Control (VVC

plus

) improves the dynamics
and the stability, both when the speed reference is
changed and in relation to the load torque.

1.1.6 Power Factor

1 1

The power factor is the relation between I1

U

×

Power factor

3 ×

=

3 ×

I

1 ×

COS

I

RMS

ϕ

U

×

and I

RMS

.

The power factor for 3-phase control:

I

×

cos

ϕ1

1

=

I

RMS

I

1

=

since cos

I

RMS

ϕ1 = 1

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.

2

2

I

RMS

=

I

+

1

2

I

+

I

+ . . +

5

7

2

I

n

In addition, a high-power factor indicates that the different
harmonic currents are low.

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2 Safety and Conformity

VLT® Micro Drive FC 51 Design Guide

22

Installation at high altitudes

2.1 Safety

2.1.1 Safety Note

WARNING

DANGEROUS VOLTAGE

The voltage of the frequency converter is dangerous
whenever connected to mains. Incorrect installation of the
motor, frequency converter or fieldbus may cause death,
serious personal injury or damage to the equipment.
Consequently, the instructions in this manual, as well as
national and local rules and safety regulations, must be
complied with.

Safety Regulations

1. The frequency converter must be disconnected
from mains if repair work is to be carried out.
Check that the mains supply has been discon­nected and that the necessary time has passed
before removing motor and mains plugs.

2. The [Off/Reset] key on the LCP does not
disconnect the equipment from mains and is thus
not to be used as a safety switch.

3. Correct protective earthing of the equipment
must be established, the user must be protected
against supply voltage, and the motor must be
protected against overload in accordance with
applicable national and local regulations.

4. The earth leakage currents are higher than 3.5
mA.

5. Protection against motor overload is set by

1-90 Motor Thermal Protection

set 1-90 Motor Thermal Protection to data

desired,
value [ETR trip] (default value) or data value [ETR
warning]. Note: The function is initialized at 1.16
x rated motor current and rated motor frequency.
For the North American market: The ETR
functions provide class 20 motor overload
protection in accordance with NEC.

6. Do not remove the plugs for the motor and
mains supply while the frequency converter is
connected to mains. Check that the mains supply
has been disconnected and that the necessary
time has passed before removing motor and
mains plugs.

7. Check that all voltage inputs have been discon­nected and that the necessary time has passed
before commencing repair work.

. If this function is

CAUTION

At altitudes above 2 km, contact Danfoss regarding PELV.

WARNING

UNINTENDED START

1. The motor can be brought to a stop with digital
commands, bus commands, references or a local
stop, while the frequency converter is connected
to mains. If personal safety considerations make it
necessary to ensure that no unintended start
occurs, these stop functions are not sufficient.

2. While parameters are being changed, the motor
may start. Consequently, the stop key [Off/Reset]
must always be activated; following which data
can be modified.

3. A motor that has been stopped may start if faults
occur in the electronics of the frequency
converter, or if a temporary overload or a fault in
the supply mains or the motor connection ceases.

2.1.2 Safety

WARNING

HIGH VOLTAGE!

Frequency converters contain high voltage when
connected to AC mains input power. Installation, start up,
and maintenance should be performed by qualified
personnel only. Failure to perform installation, start up, and
maintenance by qualified personnel could result in death
or serious injury.

High Voltage
Frequency converters are connected to hazardous mains
voltages. Extreme care should be taken to protect against
shock. Only trained personnel familiar with electronic
equipment should install, start, or maintain this equipment.

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WARNING

UNINTENDED START!

When the frequency converter is connected to AC mains,
the motor may start at any time. The frequency converter,
motor, and any driven equipment must be in operational
readiness. Failure to be in operational readiness when the
frequency converter is connected to AC mains could result
in death, serious injury, equipment, or property damage.

Unintended Start
When the frequency converter is connected to the AC
mains, the motor may be started by means of an external
switch, a serial bus command, an input reference signal, or
a cleared fault condition. Use appropriate cautions to
guard against an unintended start.

WARNING

DISCHARGE TIME!

Frequency converters contain DC-link capacitors that can
remain charged even when the frequency converter is not
powered. To avoid electrical hazards, disconnect AC mains,
any permanent magnet type motors, and any remote DC­link power supplies, including battery backups, UPS and
DC-link connections to other frequency converters. Wait for
the capacitors to fully discharge before performing any
service or repair work. The amount of wait time is listed in
the Discharge Time table. Failure to wait the specified time
after power has been removed before doing service or
repair could result in death or serious injury.

Size Minimum waiting time [min]

M1, M2 and M3 4

M4 and M5 15

Table 2.1 Discharge Time

2.1.3 Disposal Instruction

product complies with the relevant EU directives. The CE
label says nothing about the specifications or quality of
the product. Frequency converters are regulated by three
EU directives:
The machinery directive (98/37/EEC)
All machines with critical moving parts are covered by the
machinery directive of January 1, 1995. Since a frequency
converter is largely electrical, it does 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. Danfoss do this by means of a manufacturer's
declaration.
The low-voltage directive (73/23/EEC)
Frequency converters must be CE labeled in accordance
with the low-voltage directive of January 1, 1997. The
directive applies to all electrical equipment and appliances
used in the 50-1000 V AC and the 75-1500 V DC voltage
ranges. Danfoss CE-labels in accordance with the directive
and issues a declaration of conformity upon request.
The EMC directive (89/336/EEC)
EMC is short for electromagnetic compatibility. The
presence of electromagnetic compatibility means that the
mutual interference between different components/
appliances does not affect the way the appliances work.
The EMC directive came into effect January 1, 1996.
Danfoss CE-labels in accordance with the directive and
issues a declaration of conformity upon request. To carry
out EMC-correct installation, see the instructions in this
Design Guide. In addition, Danfossspecifies which
standards our products comply with. Danfossoffers the
filters presented in the specifications and provide other
types of assistance to ensure the optimum EMC result.

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. It must be
noted that the responsibility for the final EMC properties of
the appliance, system or installation rests with the installer.

2 2

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 2.2

2.2 CE Labeling

2.2.1 CE Conformity and Labeling

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

MG02K202 - VLT® is a registered Danfoss trademark

2.2.2 What is Covered

The EU "
89/336/EEC" outline three typical situations of using a
frequency

and CE Labeling for EMC coverage and CE labeling.

Guidelines on the

converter. See 2.2.3 Danfoss Frequency Converter

1. The frequency converter is sold directly to the
end-consumer. The frequency converter is for
example sold to a DIY market. The end-consumer
is a layman. He installs the frequency converter
himself for use with a hobby machine, a kitchen
appliance, etc. For such applications, the

Application of Council Directive

11

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frequency converter must be CE labeled in
accordance with the EMC directive.

22

2. 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. Neither the
frequency converter nor the finished plant has 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.

3. The frequency converter is sold as part of a
complete system. The system is being marketed
as complete and could for example, be an air­conditioning 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
chosen, the entire system does not have to be
tested.

Danfoss specifies which our different products comply
with.

Danfoss
obtain the best EMC result.

provides other types of assistance that can help to

2.2.4 Compliance with EMC Directive
89/336/EEC

As mentioned, the frequency converter is mostly used by
professionals
forming part of a larger appliance, system, or installation. It
must be noted that the responsibility for the final 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.

The frequency converter has been designed to meet the
IEC/EN 60068-2-3 standard, EN 50178 9.4.2.2 at 50 °C.

2.3

of the trade as a complex component

Aggressive Environments

2.2.3 Danfoss Frequency Converter and CE
Labeling

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 different specifi­cations. Check what a given CE label specifically covers.

The covered specifications can be very different and a CE
label may therefore give the installer a false feeling 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, Danfoss
guarantees compliance with the low-voltage directive.
Danfoss issues a declaration of conformity that confirms
our CE labeling in accordance with the low-voltage
directive.

The CE label also applies to the EMC directive provided
that the instructions for EMC-correct installation and
filtering are followed. On this basis, a declaration of
conformity in accordance with the EMC directive is issued.

A frequency converter contains many mechanical and
electronic components. All are to some extent vulnerable
to environmental effects.

CAUTION

The frequency converter should not be installed in
environments with airborne liquids, particles, or gases
capable of affecting 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.

Liquids can be carried through the air and condense in the
frequency converter and may cause corrosion of
components and metal parts. Steam, oil, and salt water
may cause corrosion of components and metal parts. In
such environments, use equipment with enclosure rating
IP54. As an extra protection, coated printed circuit boards
can be ordered as an option. (Standard on some power
sizes.)

Airborne Particles such as dust may cause mechanical,
electrical, or thermal failure in the frequency converter. A
typical indicator of excessive levels of airborne particles is
dust particles around the frequency converter fan. In dusty
environments, use equipment with enclosure rating IP54 or
a cabinet for IP20/TYPE 1 equipment.

The Design Guide offers detailed instructions for instal­lation to ensure EMC-correct installation. Furthermore,

12 MG02K202 - VLT® is a registered Danfoss trademark

In environments with high temperatures and humidity,
corrosive gases such as sulphur, nitrogen, and chlorine

SYSTEM CURVE

FAN CURVE

PRESSURE%

130BA780.10

A

B

C

0

20

40

60

80

100

120

20 40 60 80 100 120 140 160 180

VOLUME%

120

100

80

60

40

20

0

20 40 60 80 100 120 140 160 180

120

100

80

60

40

20

0 20 40 60 80 100 120 140 160 180

Voume %

Voume %

INPUT POWER % PRESSURE %

SYSTEM CURVE

FAN CURVE

A

B

C

130BA781.10

ENERGY

CONSUMED

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compounds causes chemical processes on the frequency
converter components.

Such chemical

reactions rapidly affects and damages 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.

NOTE

Mounting frequency converters
increases the risk of stoppages and considerably reduces
the life of the frequency converter.

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.

in aggressive environments

2.5.2 The Clear Advantage - Energy Savings

The clear advantage of using a frequency converter for
controlling the speed of fans or pumps lies in the
electricity savings.
When comparing with alternative control systems and
technologies, a frequency converter is the optimum energy
control system for controlling fan and pump systems.

Illustration 2.1 The graph is Showing Fan Curves (A, B, and C) for
Reduced Fan Volumes.

2 2

2.4 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 floors of
production premises, as well as in panels bolted to walls or
floors.

IEC/EN 60068-2-6 Vibration (sinusoidal) - 1970
IEC/EN 60068-2-64 Vibration, broad-band random

Table 2.3

2.5 Advantages

2.5.1 Why use a Frequency Converter for

Controlling Fans and Pumps?

A frequency converter takes advantage of the fact that
centrifugal fans and pumps follow the laws of propor­tionality for such fans and pumps. For further information
see 2.5.3 Example of Energy Savings.

Illustration 2.2 When using a frequency converter to reduce fan

MG02K202 - VLT® is a registered Danfoss trademark

capacity to 60% - more than 50% energy savings may be
obtained in typical applications.

13

n

100%

50%

25%

12,5%

50% 100%

80%

80%

175HA208.10

Power ~n

3

Pressure ~n

2

Flow ~n

130BA782.10

Discharge
damper

Less energy savings

IGV

Costlier installation

Maximum energy savings

130BA779.11

0 60 0 60 0 60

0

20

40

60

80

100

Discharge Damper Solution
IGV Solution
VLT Solution

Energy consumed

Energy consumed

Energy consumed

Input power %

Volume %

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2.5.3 Example of Energy Savings

that enables the frequency converter to function as a
Building Management System, BMS.

22

changing the RPM. By reducing the speed only 20% from
the rated speed, the flow is also reduced by 20%. This is
because the flow is directly proportional to the RPM. The
consumption of electricity, however, is reduced by 50%.
If the system in question only needs to be able to supply a

As shown in Illustration

2.3, the flow is controlled by
Illustration 2.5 shows typical energy savings obtainable

with 3 well-known solutions when fan volume is reduced
to i.e. 60%.
As the graph shows, more than 50% energy savings can be
achieved in typical applications.

flow that corresponds to 100% a few days in a year, while
the average is below 80% of the rated flow for the
remainder of the year, the amount of energy saved is even
more than 50%.

Illustration 2.3 describes the dependence of flow, pressure and
power consumption on RPM.
Q=Flow P=Power
Q1=Rated
Q2=Reduced flow P2=Reduced power
H=Pressure n=Speed regulation
H1=Rated pressure n1=Rated speed
H2=Reduced pressure n2=Reduced speed

flow P1=Rated power

Table 2.4 The Laws of Proportionality

Illustration 2.4 The Three Common Energy Saving Systems

Illustration 2.3 Laws of Proportionally

Q

n

1

1

=

Q

n

2

2

H

n

1

:

P

1

P

2

1

=

(

H

n

2

2

n

3

1

=

(

)

n

2

2

)

Flow

:

Pressure

Power

:

2.5.4 Comparison of Energy Savings

The Danfoss frequency converter solution offers major
savings compared with traditional energy saving solutions.
This is because the frequency converter is able to control
fan speed according to thermal load on the system and
the fact that the frequency converter has a built-in facility

14 MG02K202 - VLT® is a registered Danfoss trademark

Illustration 2.5 Energy Savings

Discharge dampers reduce power consumption somewhat.
Inlet Guide Vans offer a 40% reduction but are expensive

175HA209.11

60

50

40

30

20

10

H

s

0 100 200 300 400

(mwg)

B

C

A

750rpm

1050rpm

1350rpm

1650rpm

0

10

20

30

(kW)

40

50

60

200100 300

(

m3 /h

)

(

m3 /h

)

400

750rpm

1050rpm

1350rpm

1650rpm

P

shaft

C

1

B

1

A

1

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to install. The Danfoss frequency converter solution
reduces energy consumption

with more than 50% and is

easy to install.

2.5.5 Example with Varying Flow over 1
Year

This example is calculated based on pump characteristics
obtained from a
The result obtained shows energy savings in excess of 50%
at the given flow distribution over a year. The pay back
period depends on the price per kWh and price of
frequency converter. In this example it is less than a year
when compared with valves and constant speed.

Energy savings
P

shaft=Pshaft output

pump datasheet.

Distribution Valve regulation Frequency Converter

m3/

h

% Hours Power Consump-

- B

A1

1

tion

kWh A1 - C

control

Power Consump-

tion

kWh

1

350 5 438 42.5 18.615 42.5 18.615
300 15 1314 38.5 50.589 29.0 38.106
250 20 1752 35.0 61.320 18.5 32.412
200 20 1752 31.5 55.188 11.5 20.148
150 20 1752 28.0 49.056 6.5 11.388
100 20 1752 23.0 40.296 3.5 6.132

100 8760 275.064 26.801

Σ

Table 2.5

2.5.6 Better Control

If a frequency converter is used for controlling the flow or
pressure
A frequency converter can vary the speed of the fan or
pump, obtaining variable control of flow and pressure.
Furthermore, a frequency converter can quickly adapt the
speed of the fan or pump to new flow or pressure
conditions in the system.
Simple control of process (Flow, Level or Pressure) utilizing
the built-in PI control.

of a system, improved control is obtained.

2 2

Illustration 2.6 Flow Distribution over 1 Year

Illustration 2.7

2.5.7 Star/Delta Starter or Soft-starter not
Required

When larger motors are started, it is necessary in many
countries to use equipment that limits the start-up current.
In more traditional systems, a star/delta starter or soft­starter is widely used. Such motor starters are not required
if a frequency converter is used.

MG02K202 - VLT® is a registered Danfoss trademark

15

Full load

% Full load current

& speed

500

100

0

0 12,5 25 37,5 50Hz

200

300

400

600

700

800

4

3

2

1

175HA227.10

M

- +

M

M

x6 x6

x6

175HA205.12

Valve
posi­tion

Starter

Fuses

LV

supply

P.F.C

Flow

3-Port
valve

Bypass

Return

Control

Supply
air

V.A.V
outlets

Duct

P.F.C

Mains

Fuses

Starter

Bypass

supply

LV

Return

valve

3-Port

Flow

Control

Valve
posi­tion

Starter

Power
Factor
Correction

Mains

IGV

Mechanical
linkage
and vanes

Fan

Motor
or
actuator

Main
B.M.S

Local
D.D.C.
control

Sensors
PT

Pressure
control
signal
0/10V

Temperature
control
signal
0/10V

Control

Mains

Cooling section Heating section

Fan sectionInlet guide vane

Pump Pump

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As illustrated in Illustration 2.8, a frequency converter does
not consume more than rated current.

1

VLT® Micro Drive
2 Star/delta starter
3 Soft-starter

22

4 Start directly on mains

Table 2.6

2.5.8 Using a Frequency Converter Saves
Money

Example 2.5.9 Without a Frequency Converter shows that a
lot of equipment is not required when a frequency
converter is used. It is possible to calculate the cost of
installing the two different systems. In the example, the
two systems can be established at roughly the same price.

Illustration 2.8

2.5.9 Without a Frequency Converter

D.D.C.=Direct Digital Control E.M.S.=Energy Management system
V.A.V.=Variable Air Volume
Sensor P=Pressure Sensor T=Temperature

Table 2.7 Fan System made in the Traditional Way

16 MG02K202 - VLT® is a registered Danfoss trademark

Illustration 2.9

175HA206.11

Pump

Flow

Return

Supply
air

V.A.V
outlets

Duct

Mains

Pump

Return

Flow

Mains

Fan

Main
B.M.S

Local
D.D.C.
control

Sensors

Mains

Cooling section Heating section

Fan section

Pressure
control
0-10V
or
0/4-20mA

Control
temperature
0-10V
or
0/4-20mA

Control
temperature
0-10V
or
0/4-20mA

VLT

M

- +

VLT

M

M

PT

VLT

x3 x3

x3

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2.5.10 With a Frequency Converter

Illustration 2.10 Fan System Controlled by Frequency Converters

2 2

MG02K202 - VLT® is a registered Danfoss trademark

17

130BB892.10

100%

0%

-100%

100%

Local
reference
scaled to
Hz

Auto mode

Hand mode

LCP Hand on,
off and auto
on keys

Local

Remote

Reference

Ramp

P 4-10
Motor speed
direction

To motor
control

Reference
handling
Remote
reference

P 4-14
Motor speed
high limit [Hz]

P 4-12
Motor speed
low limit [Hz]

P 3-4* Ramp 1
P 3-5* Ramp 2

Hand
On

Off
Reset

Auto
On

130BB893.10

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3

Introduction to VLT® Micro Drive

VLT® Micro Drive FC 51 Design Guide

33

3.1 Control Structures

In 1-00 Configuration Mode it can be selected if open or
closed loop is to be used.

3.1.1 Control Structure Open Loop

Illustration 3.1 Open Loop Structure

In the configuration shown in Illustration 3.1, 1-00 Configu-
ration Mode is set to [0] Open loop. The resulting reference

the reference handling system or the local reference

from
is received and fed through the ramp limitation and speed
limitation before being sent to the motor control. The
output from the motor control is then limited by the
maximum frequency limit.

reference. In this mode, it is possible to control the
frequency

converter via the digital inputs and RS-485. See
more about starting, stopping, changing ramps and
parameter set-ups etc. in parameter group 5-1* (Digital
Inputs) or parameter group 8-5* (Serial Communication).

3.1.2 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/digital
inputs or serial bus. If allowed in 0-40 [Hand on] Key on

LCP, 0-44 [Off/Reset] Key on LCP, and 0-42 [Auto on] Key on
LCP, it is possible to start and stop the frequency converter

by LCP using the [Hand On] and [Off/Reset] keys. Alarms
can be reset via the [Off/Reset] key. After pressing the
[Hand On] key, the frequency converter goes into Hand
Mode and follows (as default) the local reference set by

using the LCP potentiometer (LCP 12) or [▲]/[▼] (LCP 11).
The potentiometer can be disabled by parameter P6-80. If
potentiometer is disabled, arrow keys can be used for
adjusting reference.

After pressing the [Auto On] key, the frequency converter
goes into Auto mode and follows (as default) the remote

18 MG02K202 - VLT® is a registered Danfoss trademark

Illustration 3.2

Local reference forces the configuration mode to open

independent on the setting of 1-00 Configuration

loop,
Mode.

Local

Reference is restored at power-down.

3.1.3 Control Structure Closed Loop

The internal controller allows the frequency converter to
become an integral part of the controlled system. The
frequency converter receives a feedback signal from a
sensor in the system. It then compares this feedback to a
set-point reference value and determines the error, if any,

7-30 PI

Normal/Inverse

Control

PI

Reference

Feedback

Scale to
speed

P 4-10

Motor speed

direction

To motor
control

130BB894.11

S

100%

0%

-100%

100%

*[-1]

_

+

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between these two signals. It then adjusts the speed of the
motor to correct

this error.

For example, consider a pump application where the
speed of a pump is to be controlled so that the static
pressure in a pipe is constant. The desired static pressure
value is supplied to the frequency converter as the set­point reference. A static pressure sensor measures the

Illustration 3.3

While the default values for the frequency converter’s
Closed Loop controller often provides satisfactory
performance, the control of the system can often be
optimized by adjusting some of the Closed Loop
controller’s parameters.

actual static pressure in the pipe and supplies this to the
frequency converter as a feedback signal. If the feedback
signal is greater than the set-point reference, the
frequency converter slows down to reduce the pressure. In
a similar way, if the pipe pressure is lower than the set­point reference, the frequency converter automatically
speed up to increase the pressure provided by the pump.

3 3

MG02K202 - VLT® is a registered Danfoss trademark

19

Speed open
loop

Configuration
mode

Input command:

freeze reference

Process
control

Scale to
Hz

Scale to
process
unit

Remote
reference/
setpoint

±200%

Feedback
handling

Remote
reference in %

maxRefPCT

minRefPct

min-max ref

Freeze
reference &
increase/
decrease
reference

±100%

Input commands:

Speed up/speed down

±200%

Relative
reference
=
X+X*Y/100

±200%

External reference in %

±200%

Parameter choise:
Reference resource 1,2,3

±100%

Preset reference

Input command:
preset ref bit0, bit1, bit2

+

+

Relative scalling reference

Intern resource

Preset relative reference

±100%

Preset reference 0 ±100%
Preset reference 1 ±100%
Preset reference 2 ±100%

Preset reference 3 ±100%
Preset reference 4 ±100%
Preset reference 5 ±100%
Preset reference 6 ±100%
Preset reference 7 ±100%

Extern resource 1

No function

Analog reference
±200 %

Local bus reference
±200 %
LCP potmeter 0~100 %

Extern resource 2

No function

Analog reference
±200 %

Local bus reference
±200 %
LCP potmeter 0~100 %

Extern resource 3

No function

Analog reference
±200 %

Local bus reference
±200 %
LCP potmeter 0~100 %

Y

X

130BB900.13

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3.1.4 Reference Handling

Details for Open Loop and Closed Loop operation.

33

Illustration 3.4 Block Diagram Showing Remote Reference

The remote reference is comprised of

Preset

•

External references (analog inputs and serial

•

communication bus references)
The preset relative reference

•

Feedback controlled setpoint

•

Up to 8 preset references can be programmed in the
frequency converter. The active preset reference can be
selected using digital inputs or the serial communications
bus. The reference can also be supplied externally, most
commonly from an analog input. This external source is
selected by one of the 3 Reference Source parameters
(3-15 Reference 1 Source
3-17 Reference 3 Source). All reference resources and the
bus reference are added to produce the total external
reference. The external reference, the preset reference or
the sum of the two can be selected to be the active

20 MG02K202 - VLT® is a registered Danfoss trademark

references

, 3-16 Reference 2 Source and

reference. Finally, this reference can by be scaled using

Preset Relative Reference.

3-14

The scaled reference is calculated as follows:

Reference

= X + X ×

Where X is the external reference, the preset reference or
the sum of these and Y is 3-14 Preset Relative Reference in
[%].

If Y, 3-14 Preset Relative Reference is set to 0%, the
reference will not be affected by the scaling.

(

100

Y

)

Earth Plane

LINE

FREQUENCY

MOTOR CABLE SCREENED MOTOR

CONVERTER

Earth wire

Screen

z

z

z

L1

L2

L3

PE

U

V

W

PE

175ZA062.11

C

S

I

2

I

1

I

3

I

4

C

S

C

S

C

S

C

S

I

4

C

S

z

PE

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3.2 General Aspects of EMC

VLT® Micro Drive FC 51 Design Guide

Electrical interference 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.
As shown in Illustration 3.5
motor

cable coupled with a high dU/dt from the motor

, capacitive currents in the

voltage generate leakage currents.
The use of a screened motor cable increases the leakage
current (see Illustration 3.5) because screened cables have
higher capacitance to earth than unscreened cables. If the
leakage current is not filtered, 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 screen (I 3), there
will in principle only be a small electro-magnetic field (I4)

from the screened motor cable according to the below
figure.

screen reduces the radiated interference but increases

The
the low-frequency interference on the mains. The motor
cable screen must be connected to the frequency
converter enclosure as well as on the motor enclosure. This
is best done by using integrated screen clamps so as to
avoid twisted screen ends (pigtails). These increase the
screen impedance at higher frequencies, which reduces the
screen effect and increases the leakage current (I4).
If a screened cable is used for fieldbus, relay, control cable,
signal interface and brake, the screen must be mounted on
the enclosure at both ends. In some situations, however, it
is necessary to break the screen to avoid current loops.

3 3

Illustration 3.5 Situation that Generates Leakage Currents

If the screen is to be placed on a mounting plate for the
frequency converter, the mounting plate must be made of
metal, because the screen currents have to be conveyed
back to the unit. Moreover, ensure good electrical contact
from the mounting plate through the mounting screws to
the frequency converter chassis.

When unscreened cables are used, some emission
requirements are not complied with, although the
immunity requirements are observed.

In order to reduce the interference level from the entire
system (unit+installation), make motor and brake cables as
short as possible. Avoid placing cables with a sensitive
signal level alongside motor and brake cables. Radio
interference higher than 50 MHz (airborne) is especially

MG02K202 - VLT® is a registered Danfoss trademark

generated by the control electronics. See 6.8.4 EMC-Correct
Electrical Installation for more information on EMC.

3.2.1 Emission Requirements

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 defined in the
EMC product standard. The definitions of the 4 categories
together with the requirements for mains supply voltage
conducted emissions are given in Table 3.1.

21

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Conducted

emission

Cate-

Definition

gory

33

C1 Frequency converters installed in the

first environment (home and office)
with a supply voltage less than 1000
V.

C2 Frequency converters installed in the

first environment (home and office)
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.

C3 Frequency converters installed in the

second environment (industrial) with a
supply voltage lower than 1000 V.

C4 Frequency converters installed in the

second 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.

requirement

according to the

given in EN

limits

55011

Class B

Class A Group 1

Class A Group 2

No limit line.
An EMC plan

should be made.

When the generic emission standards are used the
frequency converters are

required to comply with the

following limits

Conducted

emission

Environment Generic standard

First
environment
(home and
office)
Second
environment
(industrial
environment)

Table 3.2

EN/IEC 61000-6-3 Emission
standard for residential,
commercial and light
industrial environments.
EN/IEC 61000-6-4 Emission
standard for industrial
environments.

requirement

according to the

limits given in

EN 55011

Class B

Class A Group 1

Table 3.1 Emission Requirements

3.2.2 EMC Test Results (Emission)

Drive type Conducted emission. Maximum shielded cable length [m] Radiated emission

Housing, trades and

light

industries

Without
external

filter

With

external

filter

Without
external

filter

Industrial environment

With

external

filter

Without
external

filter

EN 55011 Class A2 EN 55011 Class A1 EN 55011 Class B EN 55011 Class A2 EN 55011 Class A1
Without
external

filter
≤2.2 kW.
Single

230 V

phase,
≤7.5 kW. Up
to 500 VAC,
three phase
11 kW to 22
kW. Up to
500 VAC,
three phase

Table 3.3 EMC Test Result

25 - 15 50 5 15 Yes - No Yes

25 - 15 50 - 15 Yes - No Yes

25 - 15 50 - 15 Yes - No Yes

Industrial environment

With

external

filter

Without
external

filter

With

external

filter

With

external

filter

22 MG02K202 - VLT® is a registered Danfoss trademark

SMPS

130BB896.10

1

2

3

a

M

130BB901.10

1324

5

a

M

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3.2.3 Harmonics Emission Requirements

Equipment connected to the public supply network

WARNING

Cannot comply, only with power option

Options Definition
1 IEC/EN 61000-3-2 Class A for 3-phase balanced

equipment (for professional equipment only up to 1
kW total power).

2 IEC/EN 61000-3-12 Equipment 16 A-75 A and profes-

sional equipment as from 1 kW up to 16 A phase
current.

Table 3.4

3.2.4 Immunity Requirements

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 office
environment. All Danfoss frequency converters comply
with the requirements for the industrial environment and
consequently comply also with the lower requirements for
home and office environment with a large safety margin.

To

maintain PELV all connections made to the control

terminals

must be PELV, e.g. thermistor must be

reinforced/double insulated.

0.25-22 kW

1. Power supply (SMPS)

2. Optocouplers, communication between AOC and
BOC

3. Custom relays

Illustration 3.6 Galvanic Isolation

3 3

3.3 Galvanic Isolation (PELV)

3.3.1 PELV - Protective Extra Low Voltage

PELV offers 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
made as described in local/national regulations on PELV
supplies.

All control terminals and relay terminals 01-03/04-06
comply with PELV (Protective Extra Low Voltage) (Does not
apply to grounded Delta leg above 440 V).

Galvanic (ensured) isolation is obtained by fulfilling
requirements for higher isolation and by providing the
relevant creapage/clearance distances. These requirements
are described in the EN 61800-5-1 standard.

The components that make up the electrical isolation, as
described, 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 Illustration 3.7.

30-90 kW

1. Power supply (SMPS) incl. signal isolation of UDC,
indicating the intermediate current voltage.

2. Gate drive that runs the IGBTs (trigger
transformers/opto-couplers).

3. Current transducers.

4. Internal soft-charge, RFI and temperature
measurement circuits.

5. Custom relays.

Illustration 3.7 Galvanic Isolation

The functional galvanic isolation (see Illustration 3.6) is for
the RS-485 standard bus interface.

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VLT® Micro Drive FC 51 Design Guide

CAUTION

Installation at high altitude:
At altitudes above 2 km, contact Danfoss regarding PELV.

3.4 Earth Leakage Current

33

WARNING

DISCHARGE TIME

Touching the electrical parts could be fatal - even after the
equipment has been disconnected from mains.
Also make sure that other voltage inputs have been
disconnected, such as load sharing (linkage of DC
intermediate circuit), as well as the motor connection for
kinetic back-up.
Before touching any electrical parts, wait at least the
amount of time indicated in the Table 2.1

time is allowed only if indicated on the nameplate

Shorter
for the specific unit.

NOTE

Leakage Current
The earth leakage current from the frequency converter
exceeds 3.5 mA. To ensure that the earth cable has a good
mechanical connection to the earth connection, the cable
cross section must be at least 10 mm2 or 2 rated earth
wires terminated separately.
Residual Current Device protection RCD
This product can cause a DC current in the protective
conductor. Where a residual current device (RCD) is used
for protection in case of direct or indirect contact, only an
RCD of Type B is allowed on the supply side of this
product. Otherwise, another protective measure shall be
applied, such as separation from the environment by
double or reinforced insulation, or isolation from the
supply system by a transformer. See also Application Note
Protection against Electrical Hazards, MN90G.
Protective
of RCDs must always follow national and local regulations.

3.5 Extreme Running Conditions

Short Circuit (Motor Phase – Phase)
Current
in the DC link, protects the frequency converter against
short circuts. A short circuit between two output phases
causes an overcurrent in the inverter. The inverter is
turned off individually when the short circuit current
exceeds the permitted 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.

earthing of the frequency converter and the use

measurement in each of the three motor phases or

.

Switching on the Output
Switching on the output between the motor and the
frequency converter is fully permitted. The frequency
converter is not damaged in any way by switching on the
output. However, fault messages may appear.

Motor-generated Over-voltage
The voltage in the intermediate circuit is increased when
the motor acts as a generator. This occurs in following
cases:

1. The load drives the motor (at constant output
frequency from the frequency converter), that is
the load generates energy.

2. During deceleration ("ramp-down") if the moment
of inertia 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.

3.

Incorrect slip compensation setting (1-62 Slip

Compensation

The control unit may attempt to correct the ramp if
possible (2-17 Over-voltage Control.)
The inverter turns off to protect the transistors and the
intermediate circuit capacitors when a certain voltage level
is reached.

Mains Drop-out
During a mains drop-out, the frequency converter keeps
running until the intermediate circuit voltage drops below
the minimum stop level, which is typically 15% below the
frequency converter's lowest rated supply voltage. The
mains voltage before the drop-out and the motor load
determines how long it takes for the inverter to coast.

) may cause higher DC link voltage.

3.5.1 Motor Thermal Protection

To protect the application from serious damages VLT
AutomationDrive offers several dedicated features
Torque Limit: The Torque limit feature the motor is
protected for being overloaded independent of the speed.
Torque limit is controlled in 4-16 Torque Limit Motor Mode
and or 4-17 Torque Limit Generator Mode and the time
before the torque limit warning shall trip is controlled in

14-25 Trip Delay at Torque Limit

Current

Limit: The current limit is controlled in 4-18 Current
Limit and the time before the current limit warning shall
trip is controlled in 14-24 Trip Delay at Current Limit.
Min Speed Limit: (4-11 Motor Speed Low Limit [RPM] or
4-12 Motor Speed Low Limit [Hz]) limit the operating speed
range to for instance between 30 and 50/60Hz. Max Speed
Limit: (4-13 Motor Speed High Limit [RPM] or 4-19 Max
Output Frequency) limit the max output speed the can
provide

.

®

24 MG02K202 - VLT® is a registered Danfoss trademark

1.21.0 1.4

30

10

20

100

60

40

50

1.81.6 2.0

2000

500

200

400
300

1000

600

t [s]

175ZA052.12

f

OUT

= 2 x f

M,N

f

OUT

= 0.2 x f

M,N

f

OUT

= 1 x f

M,N

(par. 1-23)

IMN(par. 1-24)

I

M

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ETR (Electronic Thermal relay):

The frequency

converter 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 Illustration 3.8

Illustration 3.8 ETR: The X-axis shows the ratio between I
and I
the ETR cut of and trips the drive. 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 of at lower heat due to less cooling
of the motor. In that way the motor are protected from being
over heated even at low speed. The ETR feature is calculating
the motor temperature based on actual current and speed. The
calculated temperature is visible as a read out parameter in

16-18 Motor Thermal in the FC 51 Micro Drive Programming Guide,
MG02CX.

nominal. The Y- axis shows the time in seconds before

motor

:

motor

3 3

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4

VLT® Micro Drive Selection

4.1 Options and Accessories

4.1.1 Local Control Panel (LCP)

For detailed information on programming, see

44

Programming Guide MG02C

.

NOTE

The frequency converter can also be programmed from a
PC

RS-485

via

Software.

software can either be ordered using code number

This
130B1000 or downloaded from the DanfossWeb site: /

BusinessAreas/DrivesSolutions/software-download

com-port

by installing the MCT 10 Set-up

Operation Keys:
A

yellow light above the operation keys indicates the
active key.
[Hand on]: Starts the motor and enables control of the
frequency converter via the LCP.
[Off/Reset]: Stops the motor (off). If in alarm mode the
alarm will be reset.
[Auto on]: The frequency converter is controlled either via
control terminals or serial communication.
[Potentiometer] (LCP 12): The potentiometer works in two
ways depending on the mode in which the frequency
converter is running.
In Auto Mode the potentiometer acts as an extra
programmable analog input.
In Hand on Mode the potentiometer controls local
reference.

The LCP can be moved to the front of a cabinet by using
the remote build-in kit. The enclosure is the IP55.

Enclosure IP55 front
Max. cable length between and unit: 3 m
Communication std: RS-485
Ordering no. 132B0102

Illustration 4.1 Description of LCP Buttons and Display

Use the [Menu] key to select one of the following menus:

Status:
For readouts only.

Menu:

Quick
For access to Quick Menus 1 and 2, respectively.

Main Menu:
For access to all parameters.

Navigation Keys:
[Back]: For moving to the previous step or layer in the
navigation structure.

Arrows [▲] [▼]: For maneuvering between parameter
groups, parameters and within parameters.
[Ok]: For selecting a parameter and for accepting changes
to parameter settings.

Table 4.1 Technical Data

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4.1.2 FC 51 Mounting Instruction

Step 1
Place the bottom of the LCP in the frequency converter.

Illustration 4.2

4 4

Step 2
Push the top of the LCP into the frequency converter.

Illustration 4.3

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4.1.3 FC 51 Remote Mounting Kit Mounting Instruction

Step 1
Fit gasket on LCP in the frequency converter.

Step 2
Place

LCP on panel - see dimensions of hole on drawing.

44

Illustration 4.4

Illustration 4.5

Illustration 4.6

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Step 3
Place bracket on back of the LCP, then slide down. Tighten
screws and connect cable to LCP.

NOTE

Use the provided thread cutting screws to fasten
connector to LCP. Tightening torque: 1.3 Nm.

Step 4
Connect cable to frequency converter.

NOTE

Use the provided thread cutting screws to fasten
connector to the frequency converter. Tightening torque:

1.3 Nm.

4 4

Illustration 4.7

Illustration 4.8

Illustration 4.9

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29