Continue to Site

Eng-Tips is the largest engineering community on the Internet

Intelligent Work Forums for Engineering Professionals

  • Congratulations pierreick on being selected by the Eng-Tips community for having the most helpful posts in the forums last week. Way to Go!

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

Status
Not open for further replies.

edison123

Electrical
Oct 23, 2002
4,490
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.

vfd_drawing_page-0001_duv7se.jpg




Muthu
 
Replies continue below

Recommended for you

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
 
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.
 
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
 
Status
Not open for further replies.

Part and Inventory Search

Sponsor