Delta Tau 3U042 Reference Manual

^1 USER MANUAL

^3U03U042 Geo 3U Direct PWM Drive

(New Version)

^3 Geo 3U Direct PWM Drive, 3U042

Single Source Machine Control Power // Flexibility // Ease of Use

21314 Lassen Street Chatsworth, CA 91311 // Tel. [phone] Fax. [phone] // www.deltatau.com

^4 5xx-603729-xUx2

^5 July 26, 2006

Copyright Information

© 2006 Delta Tau Data Systems, Inc. All rights reserved.

This document is furnished for the customers of Delta Tau Data Systems, Inc. Other uses are
unauthorized without written permission of Delta Tau Data Systems, Inc. Information contained in this
manual may be updated from time-to-time due to product improvements, etc., and may not conform in
every respect to former issues.

To report errors or inconsistencies, call or email:

Delta Tau Data Systems, Inc. Technical Support

Phone: [phone]
Fax: [phone]
Email: [e-mail]
Website: http://www.deltatau.com

Operating Conditions

All Delta Tau Data Systems, Inc. motion controller products, accessories, and amplifiers contain static
sensitive components that can be damaged by incorrect handling. When installing or handling Delta Tau
Data Systems, Inc. products, avoid contact with highly insulated materials. Only qualified personnel
should be allowed to handle this equipment.

In the case of industrial applications, we expect our products to be protected from hazardous or
conductive materials and/or environments that could cause harm to the controller by damaging
components or causing electrical shorts. When our products are used in an industrial environment, install
them into an industrial electrical cabinet or industrial PC to protect them from excessive or corrosive
moisture, abnormal ambient temperatures, and conductive materials. If Delta Tau Data Systems, Inc.
products are directly exposed to hazardous or conductive materials and/or environments, we cannot
guarantee their operation.

Safety Instructions

Qualified personnel must transport, assemble, install, and maintain this equipment. Properly qualified
personnel are persons who are familiar with the transport, assembly, installation, and operation of
equipment. The qualified personnel must know and observe the following standards and regulations:

IEC 364 resp. CENELEC HD 384 or DIN VDE 0100
IEC report 664 or DIN VDE 0110
National regulations for safety and accident prevention or VBG 4

Incorrect handling of products can result in injury and damage to persons and machinery. Strictly adhere
to the installation instructions. Electrical safety is provided through a low-resistance earth connection. It is
vital to ensure that all system components are connected to earth ground.

This product contains components that are sensitive to static electricity and can be damaged by incorrect
handling. Avoid contact with high insulating materials (artificial fabrics, plastic film, etc.). Place the
product on a conductive surface. Discharge any possible static electricity build-up by touching an
unpainted, metal, grounded surface before touching the equipment.

Keep all covers and cabinet doors shut during operation. Be aware that during operation, the product has
electrically charged components and hot surfaces. Control and power cables can carry a high voltage,
even when the motor is not rotating. Never disconnect or connect the product while the power source is
energized to avoid electric arcing.

After removing the power source from the equipment, wait at least 10 minutes before touching or
disconnecting sections of the equipment that normally carry electrical charges (e.g., capacitors, contacts,
screw connections). To be safe, measure the electrical contact points with a meter before touching the
equipment.

The following text formats are used in this manual to indicate a potential for personal injury or equipment
damage. Read the safety notices in this manual before attempting installation, operation, or maintenance
to avoid serious bodily injury, damage to the equipment, or operational difficulty.

WARNING

A Warning identifies hazards that could result in personal injury or death. It
precedes the discussion of interest.

Caution

A Caution identifies hazards that could result in equipment damage. It precedes the
discussion of interest.

Note

A Note identifies information critical to the user’s understanding or use of the
equipment. It follows the discussion of interest.

REVISION HISTORY

REV. DESCRIPTION DATE CHG APPVD

1 REPLACED COVER PRODUCT PHOTO 07/25/06 CP D.DIMITRI

3U Servo Amplifier

Table of Contents

Copyright Information................................................................................................................................................i

Operating Conditions .................................................................................................................................................i

Safety Instructions.................................................................................................................................................... ii

INTRODUCTION .......................................................................................................................................................1

Compatible Motors....................................................................................................................................................2

Maximum Speed....................................................................................................................................................2

Torque...................................................................................................................................................................2

Motor Poles ..........................................................................................................................................................3

Motor Inductance..................................................................................................................................................3

Motor Resistance ..................................................................................................................................................3

Motor Back EMF ..................................................................................................................................................3

Motor Torque Constant ........................................................................................................................................4

Motor Inertia ........................................................................................................................................................4

Motor Cabling ......................................................................................................................................................4

RECEIVING AND UNPACKING.............................................................................................................................5

Use of Equipment......................................................................................................................................................5

Environmental Specifications....................................................................................................................................5

Electrical Specifications............................................................................................................................................6

Recommended Fusing and Wire Gauge....................................................................................................................6

Wire Sizes .............................................................................................................................................................6

Physical Specifications..............................................................................................................................................7

MOUNTING ................................................................................................................................................................8

SYSTEM WIRING......................................................................................................................................................9

Fuse and Circuit Breaker Selection......................................................................................................................9

Use of GFI Breakers.............................................................................................................................................9

Transformer and Filter Sizing ..............................................................................................................................9

Noise Problems...................................................................................................................................................10

Operating Temperature ......................................................................................................................................10

Amplifier Cooling Considerations......................................................................................................................11

Single Phase Operation ......................................................................................................................................11

Power Supply Considerations .................................................................................................................................11

Wiring AC Input......................................................................................................................................................11

Wiring Earth-Ground ..............................................................................................................................................12

Earth Grounding Paths.......................................................................................................................................12

Wiring 24 V Logic Control .....................................................................................................................................13

Regen (Shunt) Resistor Wiring ...............................................................................................................................13

Shunt Regulation.................................................................................................................................................14

Minimum Resistance Value.................................................................................................................................14

Maximum Resistance Value................................................................................................................................14

Energy Transfer Equations.................................................................................................................................14

Bonding...................................................................................................................................................................18

Filtering...................................................................................................................................................................18

CE Filtering........................................................................................................................................................18

Input Power Filtering .........................................................................................................................................18

Motor Line Filtering...........................................................................................................................................18

3U DRIVE CONNECTIONS....................................................................................................................................21

PWM Input Connector ............................................................................................................................................21

Axis #1 PWM input connector ............................................................................................................................21

P1 (36-pin Mini-D Connector) ...........................................................................................................................21

Axis #2 PWM Input connector............................................................................................................................22

P2 (36-pin Mini-D Connector) ...........................................................................................................................22

Motor Output Connector .........................................................................................................................................23

Table of Contents ii

3U Servo Amplifier

Wiring the Motor Thermostats................................................................................................................................24

Motor Temperature Switch.................................................................................................................................24

GEO 3U PWM BACKPLANE CONNECTIONS...................................................................................................25

3UBP8A, 300-603730-10x......................................................................................................................................25

J1: 3U Geo Drive backplane slot........................................................................................................................25

J2: 24V Input Molex Connector..........................................................................................................................26

J3: FAN output Molex Connector.......................................................................................................................26

TB1: AC input Power and Regen Resistor Connector........................................................................................26

TB2: Regen Resistor Connector .........................................................................................................................26

DIRECT PWM COMMUTATION CONTROLLER SETUP ..............................................................................28

Key Servo IC Variables...........................................................................................................................................28

Key Motor Variables...............................................................................................................................................28

DC BRUSH MOTOR DRIVE SETUP WITH NON-TURBO PMAC ..................................................................29

Hardware Connection ........................................................................................................................................29

I-Variable Setup..................................................................................................................................................29

DC BRUSH MOTOR DRIVE SETUP WITH TURBO PMAC ............................................................................31

Commutation Phase Angle: Ixx72...........................................................................................................................31

Special Instructions for Direct-PWM Control of Brush Motors..............................................................................31

Testing PWM and Current Feedback Operation .....................................................................................................32

Purpose...............................................................................................................................................................33

Preparation.........................................................................................................................................................33

Position Feedback and Polarity Test..................................................................................................................34

PWM Output and ADC Input Connection ..............................................................................................................34

PWM/ADC Phase Match ....................................................................................................................................35

Synchronous Motor Stepper Action ....................................................................................................................35

Current Loop Polarity Check .............................................................................................................................35

Troubleshooting..................................................................................................................................................35

SETTING I2T PROTECTION .................................................................................................................................36

CALCULATING MINIMUM PWM FREQUENCY.............................................................................................37

PWM DRIVE COMMAND STRUCTURE.............................................................................................................38

Default Mode...........................................................................................................................................................38

Enhanced Mode.......................................................................................................................................................38

TROUBLESHOOTING............................................................................................................................................39

Error Codes .............................................................................................................................................................39

3U Drive Status Display Codes ..........................................................................................................................39

Status LEDs (for older and newer revision) 3U042............................................................................................40

Amplifier stops and displays a code....................................................................................................................41

APPENDIX A.............................................................................................................................................................42

PWM Cable Ordering Information..........................................................................................................................42

Mating Connector and Cable Kits...........................................................................................................................42

Connector and pins Part numbers ......................................................................................................................42

Motor Cable Drawing..............................................................................................................................................43

3U042 (CABKIT3C) ...........................................................................................................................................43

APPENDIX B.............................................................................................................................................................44

Regenerative Resistor: GAR78/48 .........................................................................................................................44

APPENDIX C.............................................................................................................................................................46

3U Rack DIMENSIONS .........................................................................................................................................46

Table of Contents iii

3U Servo Amplifier

Table of Contents iv

3U Servo Amplifier

Table of Contents v

3U Servo Amplifier

INTRODUCTION

This document provides user data and support for the 3U Geo Direct PWM drives 3U042. Geo drives are
brushless drive amplifier modules designed and manufactured by Delta Tau Data Systems, Inc.

The 3U042 is a 3U size Geo Direct PWM amplifier designed to drive up to two axis with 4A RMS
continuous and 8A RMS peak (2 seconds). These drives are low power amplifiers designed to drive
permanent magnet brushless (rotary or linear), AC induction and DC Brush type motors from PWM
(pulse width modulated) command signals. These drive systems are designed to fit into a standard 3U
rack. The 3U Geo Direct PWM drives will operate directly off the power mains wired to the backplane,
typically 230VAC or 110VAC, three phase or single phase with the appropriate derating. An external
power supply of +24 VDC @1A (unregulated) is required for logic power allowing the user to control
motor power separately from control logic power. The amplifiers are interfaced to a PMAC controller via
ACC-24E2, ACC-24E2M, ACC-8F or ACC-8FS or other digital output servos.

These drive amplifiers are designed to receive logic-level direct digital PWM motor voltage command
from the controller and convert them to high voltage for motor control. They provide the power
conversion, motor current sense feedback to the controller, and comprehensive system protection. Each
drive also accepts motor thermal overload sensors for drive shut down on motor over temperature. The
host controller provides all other motor control functions.

Product Features:

Simple wiring •

•

High power density

•

Extensive fault protection

•

Locking motor connectors

•

Closed loop hall effect current sensors

•

Direct line connection with Soft Start

•

Separate logic and motor power control

•

3U format for small size and easy support

•

Full isolation for PMAC and user interfaces

•

Direct PWM control for best performance and cost

•

Shunt Regulator (requires external Resistor) for Bus power control

•

Auto ranging Shunt Regulator automatically selects for 115 or 230V operation

The 3U Geo Direct PWM drives consist of three basic components: 3U format Drive Module, backplane
that gives access for the power supply and associated metal work with fan for keeping the drive cool.
Both the drive modules and backplane may be purchased separately as spares. This family of products is
further supported with the availability of cable or connector kits and compatible shunt regulator resistor
(regen resistor).

The amplifier has many protection features to ensure the proper operation and protection of all of the
components connected to the unit. When the amplifier detects a fault, the unit will display a character
indicating the type of fault. Even though backup protection is provided, the PMAC controller should
have the I

2

T protection variables set up to protect the amplifier from over current over time.

The following is a list of the faults detected by the logic of the amplifier:

•

Instantaneous over current

•

Integrated current over time (I

Backplane Board 1

2

T)

3U Servo Amplifier

Motor over temperature (input from motor) •

•

Under voltage

•

IGBT thermal failure

•

PWM fault

•

Over voltage

•

Ground fault

•

Minimum dead time protection

•

Shoot through protection

Note:

The 3U drive products are available in kit-form. The electronics on these products are
subject to damage by static electricity. Handle it as little as possible. Use ground wrist
straps when handling. Do not allow static-charge holding materials (paper, plastic, etc.)
to come in near proximity of the product.

Typically, the position feedback is fed to the PMAC controller via the available accessories and is not part
of the 3U drive amplifier. Thus, the position feedback is not to be connected to the amplifier in any

way.

Compatible Motors

The 3U Geo Direct PWM product line is capable of interfacing to a wide variety of motors. The 3U Geo
Direct PWM drives can be used with almost any type of three-phase brushless motor, including DC
brushless rotary, AC brushless rotary, induction, and brushless linear motors. Motor selection for an
application is a science in itself and cannot be covered in this manual. However, some basic
considerations and guidelines are offered. Motor manufacturers include a host of parameters to describe
their motor.

Some basic equations can help guide an applications engineer to mate a proper drive with a motor. A
typical application accelerates a load to a speed, running the speed for a while and then decelerating the
load back into position.

Maximum Speed

The motor’s maximum rated speed is given. This speed may or may not be achievable in a given system.
The speed could be achieved if enough voltage and enough current loop gain are available. Also,
consider the motor’s feedback adding limitations to achievable speeds. The load attached to the motor
also limits the maximum achievable speed. In addition, some manufacturers will provide motor data with
their drive controller, which is tweaked to extend the operation range that other controllers may be able to
provide. In general, the maximum speed can be determined by input voltage line-to-line divided by Kb
(the motor’s back EMF constant). It is wise to de-rate this a little for proper servo applications.

Torque

The torque required for the application can be viewed as both instantaneous and average. Typically, the
instantaneous or peak torque is calculated as a sum of machining forces or frictional forces plus the forces
required to accelerate the load inertia. The machining or frictional forces on a machine must be
determined by the actual application. The energy required to accelerate the inertia follows the equation: t
= JA, where t is the torque in pound-feet required for the acceleration, J is the inertia in pound-feet­second squared, and A is in radians per second per second. The required torque can be calculated if the
desired acceleration rate and the load inertia reflected back to the motor are known. The t-JA equation
requires that the motor’s inertia be considered as part of the inertia-requiring torque to accelerate.

Once the torque is determined, the motor’s specification sheet can be reviewed for its torque constant
parameter (Kt). The torque required at the application divided by the Kt of the motor provides the peak

Backplane Board 2

3U Servo Amplifier

current required by the amplifier. A little extra room should be given to this parameter to allow for good
servo control.

Most applications have a duty cycle in which the acceleration profile occurs repetitively over time.
Calculating the average value of this profile gives the continuous rating required by the amplifier.
Applications also concern themselves with the ability to achieve a speed. The requirements can be
reviewed by either defining what the input voltage is to the drive, or defining what the voltage
requirements are at the motor. Typically, a system is designed at a 230 or 480V input line. The motor
must be able to achieve the desired speed with this voltage limitation. This can be determined by using
the voltage constant of the motor (Kb), usually specified in volts-per-thousand rpm. The application
speed is divided by 1000 and multiplied by the motor’s Kb. This is the required voltage to drive the
motor to the desired velocity. Headroom of 20% is suggested to allow for good servo control.

Peak Torque

The peak torque rating of a motor is the maximum achievable output torque. It requires that the amplifier
driving it be able to output enough current to achieve this. Many drive systems offer a 3:1 peak-to­continuous rating on the motor, while the amplifier has a 2:1 rating. To achieve the peak torque, the drive
must be sized to be able to deliver the current to the motor. The required current is often stated on the
datasheet as the peak current through the motor. In some sense, it can also be determined by dividing the
peak amplifier's output rating by the motor’s torque constant (Kt).

Continuous Torque

The continuous torque rating of the motor is defined by a thermal limit. If more torque is consumed from the
motor than this on average, the motor overheats. Again, the continuous torque output of the motor is subject
to the drive amplifier’s ability to deliver that current. The current is determined by the manufacturer’s
datasheets stating the continuous RMS current rating of the motor and can also be determined by using the
motor’s Kt parameter, usually specified in torque output per amp of input current.

Motor Poles

Usually, the number of poles in the motor is not a concern to the actual application. However, it should
be noted that each pole-pair of the motor requires an electrical cycle. High-speed motors with high motor
pole counts can require high fundamental drive frequencies that a drive amplifier may or may not be able
to output. In general, drive manufacturers with PWM switching frequencies (16KHz or below) would
like to see commutation frequencies less than 400 Hz. The commutation frequency is directly related to
the number of poles in the motor.

Motor Inductance

Typically, motor inductance of servomotors is 1 to 15 mH. The Geo drive product series can drive this
range easily. On lower-inductance motors (below 1mH), problems occur due to PWM switching where
heating currents flow through the motor, causing excessive energy waste and heating. If an application
requires a motor of less than 1mH, external inductors are recommended to increase that inductance.
Motors with inductance in excess of 15mH can still be driven, but are slow to react and typically are out
of the range of high performance servomotors.

Motor Resistance

Motor resistance is not really a factor in determining the drive performance, but rather, comes into play
more with the achievable torque or output horsepower from the motor. The basic resistance shows up in
the manufacturer’s motor horsepower curve.

Motor Back EMF

The back EMF of the motor is the voltage that it generates as it rotates. This voltage subtracts from the
bus voltage of the drive and reduces the ability to push current through the motor. Typical back EMF
ratings for servomotors are in the area of 8 to 200 volts-per-thousand rpm. The Geo drive product series

Backplane Board 3

3U Servo Amplifier

can drive any range of back EMF motor, but the back EMF is highly related to the other parameters of the
motor such as the motor inductance and the motor Kt. It is the back EMF of the motor that limits the
maximum achievable speed and the maximum horsepower capability of the motor.

Motor Torque Constant

Motor torque constant is referred to as Kt and usually it is specified in torque-per-amp. It is this number
that is most important for motor sizing. When the load that the motor will see and the motor’s torque
constant is known, the drive amplifier requirements can be calculated to effectively size a drive amplifier
for a given motor. Some motor designs allow Kt to be non-linear, in which Kt will actually produce less
torque per unit of current at higher output speeds. It is wise to de-rate the systems torque producing
capability by 20% to allow headroom for servo control.

Motor Inertia

Motor inertial comes into play with motor sizing because torque to accelerate the inertia of the motor is
effectively wasted energy. Low inertia motors allow for quicker acceleration. However, consider the
reflective inertia from the load back to the motor shaft when choosing the motor’s inertial. A high ratio of
load-to-motor inertia can cause limited gains in an application if there is compliance in the transmission
system such as belt-drive systems or rubber-based couplings to the systems. The closer the rotor inertia
matches the load’s reflected inertia to the motor shaft, the higher the achievable gains will be for a given
system. In general, the higher the motor inertia, the more stable the system will be inherently.
Mechanical gearing is often placed between the load and the motor simply to reduce the reflected inertia
back to the motor shaft.

Motor Cabling

Motor cables are an integral part of a motor drive system. Several factors should be considered when
selecting motor cables. First, the PWM frequency of the drive emits electrical noise. Motor cables must
have a good-quality shield around them. The motor frame must also have a separate conductor to bring
back to the drive amplifier to help quench current flows from the motor due to the PWM switching noise.
Both motor drain wire and the cable shield should be tied at both ends to the motor and to the drive
amplifier.

Another consideration in selecting motor cables is the conductor-to-conductor capacitance rating of the
cable. Small capacitance is desirable. Longer runs of motor cable can add motor capacitance loading to
the drive amplifier causing undesired spikes of current. It can also cause couplings of the PWM noise
into the earth grounds, causing excessive noise as well. Typical motor cable ratings would be 50 pf per
foot maximum cable capacitance.

Another factor in picking motor cables is the actual conductor cross-sectional area. This refers to the
conductor’s ability to carry the required current to and from the motor. When calculating the required
cable dimensions, consider agency requirements, safety requirements, maximum temperature that the
cable will be exposed to, the continuous current flow through the motor, and the peak current flow
through the motor. Typically, it is not suggested that any motor cable be less than 14 AWG.

The motor cable’s length must be considered as part of the application. Motor cable length affects the
system in two ways. First, additional length results in additional capacitive loading to the drive. The
drive’s capacitive loading should be kept to no more than 1000 pf. Additionally, the length sets up
standing waves in the cable, which can cause excessive voltage at the motor terminals. Typical motor
cable length runs of 200 feet for 230V systems and 50 feet for 480V systems are acceptable. Exceeding
these lengths may put other system requirements in place for either a snubber at the motor end or a series
inductor at the drive end. The series inductor at the drive end provides capacitance loading isolation from
the drive and slows the rise time of the PWM signal into the cable, resulting in less voltage overshoot at
the motor.

Backplane Board 4

3U Servo Amplifier

RECEIVING AND UNPACKING

Delta Tau products are thoroughly tested at the factory and carefully packaged for shipment. When the
3U Geo Direct PWM Drive is received, there are several things to be done immediately:

1. Observe the condition of the shipping container and report any damage immediately to the
commercial carrier that delivered the drive.

2. Remove the control from the shipping container and remove all packing materials. Check all
shipping material for connector kits, documentation, CD ROM, or other small pieces of equipment.
Be aware that some connector kits and other equipment pieces may be quite small and can be
accidentally discarded if care is not used when unpacking the equipment. The container and packing
materials may be retained for future shipment.

3. Verify that the part number of the drive received is the same as the part number listed on the purchase
order.

4. Inspect the drive for external physical damage that may have been sustained during shipment and
report any damage immediately to the commercial carrier that delivered the drive.

5. Electronic components in this amplifier are design-hardened to reduce static sensitivity. However,
use proper procedures when handling the equipment.

6. If the 3U Geo Direct PWM Drive is to be stored for several weeks before use, be sure that it is stored
in a location that conforms to published storage humidity and temperature specifications stated in this
manual.

Use of Equipment

The following restrictions will ensure the proper use of the 3U Geo Direct PWM Drive:

The components built into electrical equipment or machines can be used only as integral components

•

of such equipment.

•

The 3U Geo Direct PWM Drives are to be used only on grounded three-phase industrial mains supply

networks (TN-system, TT-system with grounded neutral point).

•

The 3U Geo Direct PWM Drives must not be operated on power supply networks without a ground or

with an asymmetrical ground.

•

If the 3U Geo Direct PWM Drives are used in residential areas, or in business or commercial

premises, implement additional filter measures.

•

The 3U Geo Direct PWM Drives may be operated only in a closed switchgear cabinet, taking into

account the ambient conditions defined in the environmental specifications.

Delta Tau guarantees the conformance of the 3U Geo Direct PWM Drives with the standards for
industrial areas stated in this manual, only if Delta Tau components (cables, controllers, etc.) are used.

Environmental Specifications

Description Unit Specifications

Operating Temperature °C +0 to 45°C. Above 45°C, derate the continuous peak output current by 2.5%

per °C above 45°C. Maximum Ambient is 55°C
Rated Storage Temperature °C -25 to +70
Humidity % 10% to 90% non-condensing
Shock Call Factory
Vibration Call Factory
Operating Altitude Feet

(Meters)

Air Flow Clearances in (mm) 3" (76.2mm) above and below unit for air flow

To 3300 feet (1000 meters). Derate the continuous and peak output current

by 1.1% for each 330 feet (100meters) above the 3300 feet

Backplane Board 5

3U Servo Amplifier

Electrical Specifications

Output Circuits (axes)

Nominal Input Voltage (VAC)
Rated Input Voltage (VAC)
Rated Continuous Input Current (A AC

Rated Input Power (Watts)
Frequency (Hz)
Phase Requirements
Charge Peak Inrush Current (A)
Main Bus Capacitance (µf), backplane

board
Rated Output Voltage (V)
Rated Cont. Output Current per Axis
Peak Output Current (A) for 2 seconds
Rated Output Power per Axis (Watts)

Nominal DC Bus
Over-voltage Trip Level (VDC)
Under-voltage Lockout Level (VDC)

Turn-On Voltage (VDC)
Turn-Off Voltage (VDC)
Maximum Current (A)
Recommended Current (A)
Minimum Resistance (Ohms)
Maximum Power (W)
Recommended Load Resistor (300 W

Max.)
Input Voltage (VDC)
Input Current (A)
Inrush Current (A)

Resolution (bits)
Full-scale Signed Reading (±A)

Maximum PWM Frequency (kHz) @ rated
current

Minimum Dead Time (µs)
Charge Pump Time (% of PWM period.)

Recommended Fusing and Wire Gauge

RMS

)

1Φ or 3Φ

2

230

97-265

5.28

2103

50/60

940
138

4

8
956
325
410

10
392
372

GAR48

20-27

1
2

12

13.01

12

1
5

Model Recommended Fuse (FRN/LPN) Recommended Wire Gauge*

3U042 20 12 AWG

* See local and national code requirements

Wire Sizes

3U Geo Direct PWM Drive electronics create a DC bus by rectifying the incoming AC electricity. The
current flow into the drive is not sinusoidal but rather a series of narrow, high-peak pulses. Keep the
incoming impedance small so that these current pulses are not hindered. Conductor size, transformer size,
and fuse size recommendations may seem larger than normally expected. All ground conductors should
be 8AWG minimum using wires constructed of many strands of small gauge wire. This provides the
lowest impedance to high-frequency noises.

Backplane Board 6

3U Servo Amplifier

Physical Specifications

L x W x H (inches) 6.30 x 2.40 x 5.08

Width (3U rack slots) 3

Weight: drive only with front panel

(w/o backplane and side panels)

Backplane Width (3U rack slots) 3

Backplane Weight 0.275kgs (0.6lbs)

Terminal Connections Torque to 20 in-lb

3U042

0.9kgs (2.0lbs)

Backplane 3UBP8A

Backplane Board 7

3U Servo Amplifier

MOUNTING

The 3U Geo Direct PWM drives are designed to be installed in an enclosure whose ambient temperature
does not exceed 55 °C. It must not be exposed to conductive dust or humidity in excess of 90% non­condensing. Corrosive gasses, corrosive dust, and other contaminants must be kept out of the drive
enclosure.

2.39

DELTA

TAU

2-AXIS PWM AMPLIFIER

230 VAC INPUT -4A rms CONT/8A rms PEAK

MOTOR

O.T .

AMPLIFIER

STATUS

PWM

INPUT

1

ENA 1

ENA 2

PWR

PWM

INPUT

2

U

V

W

U

V

W

M
O
T
O
R

1

M
O
T
O
R

2

5.08

6.30

3.94

MODEL 3U42

FACEPLATE

3 SLOT

The drive rack is mounted to a back panel. The back panel should be unpainted and electrically
conductive to allow for reduced electrical noise interference. The back panel is machined to accept the
mounting bolt pattern of the drive. Make sure that all metal chips are cleaned up before the drive is
mounted so there is no risk of getting metal chips inside the drive.

The 3U rack is mounted to the back panel through 4 x 0275”x0.400” obround, user needs to provide
screws and internal-tooth lock washers to attach at the cabinet. It is important that the teeth break through
any anodization on the drive's mounting gears to provide a good electrically conductive path in as many
places as possible. Mount the 3U rack on the back panel so there is airflow (at least three inches) at both
the top and bottom areas of the drive.

If multiple 3U Geo drives are used, they can be mounted side-by-side, leaving at least one-tenth of an
inch clearance between drives in the 3U rack. It is extremely important that the airflow is not obstructed
by the placement of conduit tracks or other devices in the enclosure.

Caution:

Units must be installed in an enclosure that meets the environmental IP rating of

the end product (ventilation or cooling may be necessary to prevent enclosure

ambient from exceeding 113° F [45° C]).

Backplane Board 8