Rockwell Automation 7000A PowerFlex Medium Voltage AC Drive (A Frame) - ForGe Control - Manual (Page 47)

Rockwell Automation Publication 7000A-UM200C-EN-P - June 2014 47
Drive Installation Chapter 2
Power and Control Wiring Drive line-ups (i.e. Drive and Input Starter) which are delivered in two or more
sections, for ease of handling, will require that the power and control wiring be
re-connected. After the sections are brought together, the power and control
wiring is to be re-connected as per the schematic drawings provided.
Control Cables
Control cable entry/exit should be located near the terminal block 'TBC' – the
customer's connections are to be routed along the empty side of the TBC
terminals. These terminals are sized to accept a maximum #14 AWG. The low
voltage signals (includes 4...20 mA) are to be connected using twisted shielded
cable, with a minimum #18 AWG.
Of special concern is the tachometer signal. Two tachometer inputs are provided
to accommodate a quadrature tachometer (senses motor direction). The
tachometer power supply is isolated and provides 15V and a ground reference.
Many tachometer outputs have an open collector output, in which case a pull-up
resistor must be added to ensure that proper signals are fed to the system logic
(see
page 163 ).
Grounding Practices The purpose of grounding is to:
• provide for the safety of personnel
• limit dangerous voltages on exposed parts with respect to ground
• facilitate proper over current device operation under ground fault
conditions, and
• provide for electrical interference suppression
Refer to the grounding diagrams that follow for ground connections. The drive’s
main ground bus must be connected to the system ground. This ground bus is
the common ground point for all grounds internal to the drive.
IMPORTANT Low voltage signals are to be connected using twisted shielded cable with the
shield connected at the signal source end only. The shield at the other end is to
be wrapped with electrical tape and isolated. Connections are to be made as
shown on the electrical drawings (ED) provided.
IMPORTANT Generally, the means used for external grounding of equipment should be in
accordance with the Canadian Electrical Code (CEC), C22.1 or the National
Electrical Code (NEC), NFPA 70 and applicable local codes.