Rockwell Automation HPK-Series Asynchronous Servo Motor User Manual
Page 9
HPK-Series Asynchronous Servo Motors 9
Publication HPK-IN001C-EN-P - June 2010
Interconnect Cables
Knowledgeable cable routing improves system electromagnetic compatibility (EMC). Refer to
Grounding of Signal Wire Shields Within a Cable for suggested cable trim lengths, and for cable
shield grounding at the motor frame.
To install the cables:
•
Keep wire lengths as short as physically possible.
•
Route signal cables away from motor and power wiring. Typical signal cables transmit
encoder, serial, or analog data at low voltages.
•
Separate cables by 0.3 m (1 ft) minimum for every 9 m (30 ft) of parallel run.
•
Ground both ends of the cable shield and twist the signal wire pairs to prevent
electromagnetic interference from other equipment.
Electrical Noise
Electromagnetic interference (EMI), commonly called noise, may adversely impact motor
performance by inducing stray signals. Effective techniques to counter EMI include filtering the
ac power, shielding and separating signal carrying lines, and practicing good grounding
techniques. Effective ac power filtering can be achieved by using isolated ac power transformers
or properly installed ac line filters. The effect of EMI on motor signals can be minimized by two
installation practices.
•
Physically separate signal lines from motor cabling and power wiring. Do not route
signal wires with motor and power wires, and do not route signal wires over the vent
openings of servo drives or other electrical power sources.
•
Ground all equipment using a single-point parallel ground system that employs ground
bus bars or large straps. If necessary, use additional electrical noise reduction techniques
to reduce EMI in a noisy environment.
IMPORTANT
The recommended wire size is based on motor current requirements and
terminal block sizing. Consult your local electrical code before selecting wire
gauge for your application
ATTENTION: High voltage can be present on power cable shielding, if the
shielding is not grounded.
Verify there is a connection to ground for all power cable shielding.
Failure to observe these safety procedures could result in personal injury or
damage to equipment.