VFD Output Reactors
VFD Output Reactors
(OP)
I'm designing a facility that has several 150-250hp pump motors on VFD's. The distance from the VFD's to the motors is less than 50ft. The motors will be inverter duty rated. The cables can either be armored cable with 1000V insulation, VFD cable, or individual wires with 1000V insulation.
I've been told that we should include output reactors as "cheap insurance", but the drive manufacturer does not require them for this short distance.
The way I see it, the reactors will help with motor efficiency & motor temperature even if voltage transients & insulation stress aren't an issue. Opinions?
I've been told that we should include output reactors as "cheap insurance", but the drive manufacturer does not require them for this short distance.
The way I see it, the reactors will help with motor efficiency & motor temperature even if voltage transients & insulation stress aren't an issue. Opinions?





RE: VFD Output Reactors
Not sure how much they really reduce motor losses.
David Castor
www.cvoes.com
RE: VFD Output Reactors
dpc, you make some good points. They also cost money, take up space, heat the VFD enclosure, and lower the voltage available at the motor terminals. They don't really seem like "cheap insurance" in this case.
RE: VFD Output Reactors
Neil
RE: VFD Output Reactors
The beauty of a reactor is, it's just copper wire on an iron core, there isn't a lot to "fail" in that system. It not only protects the motor from something that happens in the VFD, it also helps to protect the VFD output transistors from motor winding and lead cable faults. Adding a reactor delays the rise time of a fault (inductive time constant) and can give the VFD that few extra milliseconds it needs to turn off the transistors before they pop.
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RE: VFD Output Reactors
RE: VFD Output Reactors
reactors
You should at least do the math on the wasted energy and any subsequent air conditioning loads.
Keith Cress
kcress - http://www.flaminsystems.com