System Module Wire Sizes; Shielding; Emi/Rfi Shielding; Emi/Rfi Bonding - Allen-Bradley 1394 User Manual

3-4 Wiring System, Axis, and Shunt Modules, and Motors (for all systems)
Publication 1394-5.0 — May 2000

System Module Wire Sizes

All wire sizes in this manual are recommended minimums. Assume
that wires are type MTW copper wire (machine tool wire, 75° C,
minimum) per NFPA 79 unless otherwise noted. Consult the National
(or local) Electrical Code for factors related to ambient conditions,
length, etc. See your Allen-Bradley Sales Representative for more
information.

Shielding

To minimize radiated and induced noise problems or ground loops,
separate feedback, command, and other shields from each other and
connect them at a common machine or system earth ground. Connect
all shields to a single earth ground point. Refer to Grounding Your
1394 System in this chapter and Appendix B for additional
information.
Insulate the open-ended shields (resolver feedback cable at the
resolver and velocity command cable at the servo drive) so that they
do not cause ground loops.

EMI/RFI Shielding

The 1394 has an inverter carrier frequency of 5000 Hz. The drive's
output inverter switching sequence produces a carrier frequency of
10,000 Hz when measured at the motor. This can induce noise into
sensitive equipment lines adjacent to it.
ATTENTION: This system can produce
electromagnetic radiation that can cause industrial or
!
radio-controlled equipment to operate erratically and
cause possible injury to personnel. The 1394 system is
designed to be interconnected with Allen-Bradley EMI
shielded motor cables only. Do not substitute cables.
The EMI shield of the motor power cable must be
grounded at both ends to function properly.

EMI/RFI Bonding

The metal chassis of electrical components should be bonded to the
subpanel in an electrical cabinet with metal to metal contact. The
purpose of a high frequency (HF) bond is to provide HF noise
currents a path of least impedance to return to their source.