Chapter 3 – Electrical Installation
3-4 ACx=ACS/ACC/ACP ACS/ACC/ACP 604/607 Drives
armored cable must be used for motor wiring. Detailed conduit and
armored cable wiring practice guidelines are provided below.
Type MC continuous corrugated aluminum armor cable with
symmetrical grounds is the best type of wiring to provide a good low
impedance high frequency ground return path between the motor and
the drive. This helps to prevent high frequency ground current from
flowing in a potentially damaging path through the motor bearings and
connected load bearings. Type MC continuous corrugated aluminum
armor cable with symmetrical grounds is highly recommended for
motor connections to drives rated 490 KVA and larger.
Conduit
Metallic conduit must be used for motor wiring unless armored cable is
used. Where conduits must be coupled together, the joint must be
bridged with a ground conductor bonded to the conduit on each side of
the joint. The conduits must also be bonded to the drive enclosure. Use
separate conduits for input power, motor, brake resistors and control
wiring. The recommended wiring configuration is shown on page 7. Do
not run motor wiring from more than one drive in the same conduit.
Armored Cable
If metallic conduit is not used, type MC continuous corrugated
aluminum armor cable with symmetrical grounds must be used for the
motor cables. If type MC armor cables are used, the motor cables can
be run in the same cable tray as other 480V or 600V power wiring.
Control and signal cables must not be run in the same tray as power
cables.
Six conductor (3 phases and 3 grounds) type MC continuous
corrugated aluminum armor cable with symmetrical grounds is
available from the following suppliers. Trade names are in
parentheses.
Anixter Wire & Cable (Philsheath)
BICC Cables Corp. (Philsheath)
Rockbestos Co. (Gardex)
Oaknite (CLX)
Control Cables
All control cables must be shielded. As a general rule, the control
signal cable shield should be grounded directly in the ACx 600. The
other end of the shield should be left unconnected.
Twisting the signal wire with its return wire reduces disturbances
caused by inductive coupling. Pairs should be twisted as close to
terminals as possible.A double shielded twisted pair cable (Figure a,
e.g. Belden 9729) must be used for analog signals and is
recommended for the pulse encoder signals. Employ one individually
shielded pair for each signal. Do not use common return for different
analog signals.
A double shielded cable is the best alternative for low voltage digital
signals but single shielded twisted multipair cable (Figure b) is also
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