Rockwell Automation 1391ES AC Servo Controller - Manual (Page 42)

Installation
Chapter 6
6-40
To help alleviate the problem, machine power and signal lines must be
routed separately. The 1391B-ES power and signal lines must be shielded,
twisted and routed in separate ferrous metal conduit or harnesses spaced at
least 12” (304.8mm) apart. Power leads are defined here as the transformer
primary and secondary leads, motor leads and any 115V AC or above
control wiring for relays, fans, thermal protectors etc. Signal wiring is
defined as velocity command, resolver feedback, enable lines and low level
logic signal lines.
Feedback, command signal and other shields must be insulated from each
other and connected at a common machine or system earth ground in a
“star” fashion (i.e. all shields connected to a single earth ground point).
This helps to minimize radiated and induced noise problems and ground
loops. Refer to the paragraph entitled “Grounding” and Appendix B.
Open ended shields (resolver feedback cable at the resolver and velocity
command cable at the servo controller) must be insulated so that they do
not accidentally cause ground loops.
EMI Shielding
The 1391B-ES has an inverter carrier frequency of 2500 Hz. Therefore, the
system may induce noise into sensitive equipment lines adjacent to it.
ATTENTION: This controller can produce electromagnetic
radiation that may cause industrial or radio controlled
equipment to operate erratically and cause possible injury to
personnel.
The 1391B-ES system is designed to be interconnected with
Allen-Bradley EMI shielded motor cables only. Do Not
substitute cables. The EMI shield of the motor cable only, must
be grounded at both ends to function properly.
!
Important: The thermal switch and brake wires are routed near motor
power and can pickup PWM radiation. Isolation from control devices may
be required.
Grounding
All equipment and components of a machine or process system shall have
their chassis connected to a common earth ground point. This ground
system provides a low impedance path that helps minimize shock hazards
to personnel and damage to equipment caused by short circuits, transient
overvoltages and accidental connection of energized conductors to the
equipment chassis.