Hardware Ref, Installation, and Troubleshooting User guide

5Ć1
5.0 INSTALLING INPUT POWER WIRING
This chapter describes incoming line components and how to install them.
5.1 Installing Transformers and Reactors (Optional)
Input isolation transformers might be needed to help eliminate the following:
D Damaging line voltage transients from reaching the drive.
D Line noise from the drive back to the incoming power source.
D Damaging currents that could develop if a point inside the drive becomes grounded.
Observe the following guidelines when installing an isolation transformer:
D A power disconnecting device must be installed between the power line and the primary of the
transformer.
D
If the power disconnecting device is a circuit breaker , the circuit breaker trip rating must be
coordinated with the inĆrush current (10 to 12 times full load current) of the transformer .
D
An input isolation transformer rated more than 1000 KV A for 460 V AC with less than 5%
impedance should NOT be used directly ahead of the drive without additional impedance
between the drive and the transformer .
CAUTION: Distribution system capacity above the maximum recommended system KVA (1000 KVA for
460
V AC) requires the use of an isolation transformer , a line reactor , or other means of adding similar imped Ć
ance
to the drive power input. F ailure to observe these precautions could result in damage to or destruction
of the equipment.
CAUTION: When the AĆC line is shared directly with other SCRĆrectified drives, an optional snubber resistor
braking kit might be required to alleviate excess D ĆC bus voltage. F ailure to observe these precautions could
result in damage to or destruction of the equipment.
5.2 Installing Fuses for Branch Circuit Protection
Install the required, user Ćsupplied branch circuit protection fuses according to NEC/CEC guidelines.
The fuses must be installed in the line before the drive input terminals. See figures 5.1 and 5.2. F use
value selections are provided in table 3.9.
WARNING
THE NEC/CEC REQUIRES THAT UPSTREAM BRANCH PROTECTION BE PROVIDED TO PROTECT
INPUT POWER WIRING. FAILURE TO OBSERVE THIS PRECAUTION COULD RESULT IN SEVERE
BODILY INJURY OR LOS
S OF LIFE .