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line reactor protection?

line reactor protection?

line reactor protection?

(OP)
I have a question concerning code.  I have a 40 HP motor being run by an allen-bradley VFD that will be set to protect the motor.  I have the incoming line going through an 80A trip circuit breaker (which is the size A-B recommneds for the drive) and then to a line reactor.  The line reactor is rated for 55A continuous and 200% for 3 minutes.  My question is: Is the reactor sufficiently protected by the drive?  I belive a 70A (125% of 55A)breaker would be called for by code, unless somehow the drive can be considered the protection device.

Any thoughts?

Thanks,
Doug

RE: line reactor protection?

Doug,

If the reactor is part of the drive, then it isn't covered by the Code, at least not directly.

If it is external, then Article 470 applies.  I don't believe that overcurrent protection is specifically required by NEC for the reactor.  

From a practical viewpoint, the drive protection should protect the reactor against a sustained overload and the upstream breaker should protect against internal short in the reactor.

Regards,

dpc

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