Rockwell Automation 1557 MEDIUM VOLTAGE AC DRIVE - Manual (Page 194)

8-8 INSTALLATION
1557-UM050E-EN-P – June 2013
Ground Bus
The drive ground bus is accessible from its cover plates at each end of the drive. It is the responsibility of
the installer to ensure that the drive is grounded properly.
Low Voltage Wiring
A low voltage ( 110 volts/ 60 Hz ) power supply is required for drive auxiliary components. Terminal blocks
are accessible when the medium voltage door containing the low voltage compartment is in the fully open
position. Low voltage wiring is to enter the cabinet through the access openings in the floor or top plates of
the cabinet, and routed through the wire duct provided.
Tachometer Connections - The Tachometer wires must be routed in grounded steel conduit for electrical
noise suppression. The conduit must be grounded at both ends. Connect the cable shield to the drive
isolated ground bus at the drive end ONLY.
Power Connections - The drive requires a three-phase supply and an equipment-grounding conductor to
earth ground. A neutral conductor of the three-phase supply is not necessary and is usually not routed to
the drive. Three-phase wiring will connect the drive to the motor.
IMPORTANT: The CEC and NEC require that branch circuit protection of the AC line input power to the
drive be provided by a circuit breaker or fusible disconnect switch. The standard drive provides this
requirement.
IMPORTANT: The control and signal wires should be oriented a distance of at least six (6) inches
(150mm) from power cables. Additional noise suppression practices (including separate steel conduits for
signal leads, etc.) are recommended. We also recommend that 24V DC Logic wiring NOT exceed 50 feet
from the drive.
Power Cabling Access
Access plates are provided on the top and bottom plates of the cabinet. Figure 8.5 shows the typical areas
available for cables. Consult the outline drawings of the drive, as locations may change due to specific
customer requirements. Incoming cables areas are coded (P) and motor (load) cable areas are coded (L).
Low voltage wiring areas are coded (C).
The maximum recommended cable size is one 250 MCM per phase. Cable termination points are
accessible from the front of the drive with the medium voltage doors open.
Figure 8.5 – Typical Power Cabling Access (Bottom Entry shown)