Chapter 5 Installing Input Power Wiring; Installing Transformers And Reactors (Optional) - Reliance electric GV3000 Instructions Manual

5.1 Installing Transformers and Reactors (Optional)

Installing Input Power Wiring
This chapter describes incoming line components and how to install them.
Input isolation transformers might be needed to help eliminate the following:
•
Damaging line voltage transients from reaching the drive.
•
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 in-rush current (10 to 12 times full load current) of the
transformer.
•
An input isolation transformer rated more than 1000 KVA for 460 VAC with less than
5% impedance should NOT be used directly ahead of the drive without additional
impedance between the drive and the transformer.
ATTENTION: Distribution system capacity above the maximum
recommended system KVA (1000 KVA for 460 VAC) requires the use of
!
an isolation transformer, a line reactor, or other means of adding similar
impedance to the drive power input. Failure to observe these precautions
could result in damage to, or destruction of, the equipment
ATTENTION: When the AC line is shared directly with other
SCR-rectified drives, an optional snubber resistor braking kit might be
required to alleviate excess DC bus voltage. Failure to observe these
precautions could result in damage to, or destruction of, the equipment
The GV3000/SE AC line distribution system capacity is 1000 KVA, three-phase with
30,000 amps symmetrical fault current capacity with a line impedance of less than 5%.
The symmetrical fault current may be increased to 85,000 amps if the appropriate
three-phase AC line reactor is used as shown in table 5.1.
Installing Input Power Wiring
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