Feeding a VFD

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Machiavelli999

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My client wants to put a motor that is now on an across the line starter onto a VFD. The starter is in an MCC and the VFD will be outside the MCC near the motor. Do I have to gut the starter? Is there a problem with feeding the VFD through the overload relays and contactor that are in the starter?
 
Machiavelli999 said:
My client wants to put a motor that is now on an across the line starter onto a VFD. The starter is in an MCC and the VFD will be outside the MCC near the motor. Do I have to gut the starter? Is there a problem with feeding the VFD through the overload relays and contactor that are in the starter?
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I would be inclined to remove both the starter and the OL and just use the bucket OCPD to feed the VFD.
 
also any disconnect after the VFD will need axillary contacts that will shut down the VFD before the disconnect breaks the circuit as most VFD;s will not tolerate being unloaded while running, it tends to let the smoke out.
 
petersonra said:
I would be inclined to remove both the starter and the OL and just use the bucket OCPD to feed the VFD.
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...and void the UL listing of the bucket? Not to mention that many of the starters use MCP's that would be not permitted to be used without other approved components that were part of the combination starter.

Using the combination starter should meet the feeder protection requirements of 430 for ASD's.
 
weressl said:
...and void the UL listing of the bucket? Not to mention that many of the starters use MCP's that would be not permitted to be used without other approved components that were part of the combination starter.

Using the combination starter should meet the feeder protection requirements of 430 for ASD's.
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Good point about the MCP. Don't really care all that much about the UL listing of the bucket.

IIRC, an MCP has to be specifically listed for use with a particular VFD to get an SCCR for the combination if that matters any.
 
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