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Is RC dv/dt snubber same as dv/dt filter on VFD output?
3

Is RC dv/dt snubber same as dv/dt filter on VFD output?

Is RC dv/dt snubber same as dv/dt filter on VFD output?

(OP)
I am looking at the below schematic of a 3 ph VFD, which has an input reactor (with an input surge suppressor connected in parallel across the input reactor), VFD, an output reactor with a RC dv/dt snubber connected in parallel across the output reactor.

Is this RC dv/dt snubber same as dv/dt filter on VFD output?

Sorry for the picture quality. Unable to upload the pdf.



Muthu
www.edison.co.in

RE: Is RC dv/dt snubber same as dv/dt filter on VFD output?

(OP)
Thanks, gr8blu.

So, inline inductive filters (LR, LC, LRC) are better than across the line RC filters for reducing dv/dt as well as voltage spikes?

Muthu
www.edison.co.in

RE: Is RC dv/dt snubber same as dv/dt filter on VFD output?

I can't see your dwg clear enough to make out anything useful on it.

Inductors are the only components inline. A resistor or series resistor-capacitor might be put in parallel with the inductor but you won't find any combination of those components inline without the inductor being the main path.

C or R-C networks are put from phase to phase which will force a transient on one phase into the other 2, which just lowers the overall peak. Better yet is phase to ground to shunt the transients to ground.

RE: Is RC dv/dt snubber same as dv/dt filter on VFD output?

The combination of the output reactor plus the RC snubber is what comprises a DV/DT filter assembly. I suppose one could buy and install the components separately, but just buying a manufactured DV/DT filter would be much simpler.


" We are all here on earth to help others; what on earth the others are here for I don't know." -- W. H. Auden

RE: Is RC dv/dt snubber same as dv/dt filter on VFD output?

(OP)
Thanks, Jeff.

Muthu
www.edison.co.in

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