Allen-Bradley MPL-A310 Installation Instructions Manual page 7

Preventing Electrical Noise
Electromagnetic interference (EMI), commonly called noise, can cause poor motor performance
by inducing stray signals.
Follow these guidelines to prevent the effects of EMI:
•
Isolate the power transformers, or install line filters on all AC input power lines.
•
Separate signal cables from motor cabling and power wiring. Do not route signal cables
with motor and power wires, or over the vent openings of servo drives.
•
Ground all equipment by 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 noisy environments.
Refer to System Design for Control of Electrical Noise Reference Manual, publication
GMC-RM001, for additional information on reducing the effects of EMI by improving the
system level electromagnetic compatibility (EMC).
Build and Install the Cables
Correct cable routing and careful cable construction improves system electromagnetic
compatibility (EMC).
Follow these guidelines to build and install the cables:
•
Keep the wire lengths as short as possible.
•
Route noise sensitive wiring (encoder, serial, and I/O) away from input power and motor
power wiring.
•
Separate cables by 0.3 m (1 ft) minimum for every 9 m (30 ft) of parallel run.
•
Ground both ends of the encoder cable shield and twist the signal wire pairs to prevent
EMI from other equipment.
ATTENTION: High voltage can be present on the shield of a power cable, if the shield is not
grounded.
Verify that there is a connection to ground for any power cable shield.
ATTENTION: MP-Series motors produce leakage current in the protective earthing conductor that
exceeds 3.5 mA AC and/or 10 mA DC.
Be sure to properly ground the motor cables per the drive installation instructions.
MP-Series Low-inertia Servo Motor with 100 mm to 165 mm Frame Size 7
Rockwell Automation Publication MP-IN001I-EN-P - January 2015