Rockwell Automation 1302 575v AC Drive - Canada Only - Manual (Page 33)

4–5 Installation
Publication 1302-5.0 — January, 1998
Input isolation transformers may be needed to help eliminate the
following:
•
Damaging line voltage transients.
•
Line noise from the Drive back to the incoming power source.
•
Damaging currents that could develop if a point inside the Drive
becomes grounded.
Observe the following guidelines when installing an isolation
transformer:
•
A power disconnecting device must be installed between the
power line and the primary of the transformer. If the power
disconnecting device is a circuit breaker, the circuit breaker trip
rating must be coordinated with the inrush current (10 to 12
times the full load current) of the transformer.
•
Do NOT use an input isolation transformer rated more than 100
KVA for 230 VAC (or 1000 KVA for 460 VAC) with less than
5% impedance directly ahead of the Drive without additional
impedance between the Drive and the transformer.
If your 1302 application requires the use of an output transformer,
contact Allen–Bradley for assistance.
Output Contactors
!
ATTENTION: Any disconnecting means wired to
drive output terminals U,V, and W must be capable of
disabling the Drive if opened during Drive operation.
If opened during Drive operation, the Drive will
continue to produce output voltage between U, V, and
W. An auxiliary contact must be used to
simultaneously disable the Drive or output component
damage may occur.
Output contactors provide a positive means of disconnecting the
motor from the Drive. If your 1302 application requires the use of
output contactors, contact Allen–Bradley for assistance.
Mechanical Motor Overload Protection
To provide the motor with overload protection, local, national, and
international codes (for example, NEC/CEC) require that a motor
thermostat, internal to the motor, be installed or an electronic thermal
motor overload relay, sized to protect the motor, be installed between
the motor and the Drive’s output terminals.
The Electronic Thermal Overload parameter (F-14) may be used in
place of the electronic thermal motor overload relays in single motor
applications. Note, however, that temperature-sensing devices
integral to the motor are the best way of thermally-protecting AC
motors under all conditions. Parameter F-14 must be enabled to
provide overload protection. Refer to Chapter 8 for the parameter
description.