Planning the electrical installation
66
Conduit
Couple separate parts of a conduit together: bridge the joints with a ground
conductor bonded to the conduit on each side of the joint. Bond the conduits also to
the drive enclosure and motor frame. Use separate conduits for input power, motor,
brake resistor, and control wiring. When conduit is employed, type MC continuous
corrugated aluminium armor cable or shielded cable is not required. A dedicated
ground cable is always required.
Note: Do not run motor wiring from more than one drive in the same conduit.
Armored cable / shielded power cable
Six conductor (3 phases and 3 ground) type MC continuous corrugated aluminum
armor cable with symmetrical grounds is available from the following suppliers (trade
names in parentheses):
• Anixter Wire & Cable (Philsheath)
• BICC General Corp (Philsheath)
• Rockbestos Co. (Gardex)
• Oaknite (CLX).
Shielded power cables are available from Belden, LAPPKABEL (ÖLFLEX) and
Pirelli.
Selecting the control cables
Shielding
All control cables must be shielded.
Use a double-shielded twisted pair cable for analogue signals. This type of cable is
recommended for the pulse encoder signals also. Employ one individually shielded
pair for each signal. Do not use common return for different analogue signals.
A double-shielded cable is the best alternative for low-voltage digital signals but
single-shielded twisted pair cable (Figure b) is also usable.
a
A double-shielded twisted pair
cable
b
A single-shielded twisted pair ca-
ble
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