Reed frequency
Reed frequency
(OP)
We are currently working on 2000HP vertical motor (8 pole) and in the process of selecting VFD. We haven't decided which VFD to choose.
If we choose Rockewell VFD, typical CSI(Current source VFD), we would have to face potential reed frequency resonances excited by VFD output capacitors.
Is there any issue if we choose Voltage Source VFD?
If we choose Rockewell VFD, typical CSI(Current source VFD), we would have to face potential reed frequency resonances excited by VFD output capacitors.
Is there any issue if we choose Voltage Source VFD?





RE: Reed frequency
Gunnar Englund
www.gke.org
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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...
RE: Reed frequency
I'll be darned I found it here!
http://www
And also here.
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RE: Reed frequency
I'm not sure however if that is still true. I'm not in the CSI drive business, but I know there have been advancements in the power system topology that may (or may not) have solved that problem. Mainly, I think they are able to do higher speed switching now because of the advent of IGCTs, instead of the much slower GTO thyristors that were use in the past.
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RE: Reed frequency
The latter is (guessing) an electrical vibration/oscillation while the former are mechanical. That is why I needed to ask.
I have had rather nasty ringing in a system feeding an 800 kW, 690 V fan pump for a paper machine. The ringing was on the 11 kV side and caused by the step current waveform of the CSI triggering resonances between transformer leakage capacitance and cable capacitance.
Three 1200 kVA 11/.69 kV dry resin transformers lived less than two years with this ringing. Ozone production in voids in primary insulation believed to be the failure.
Gunnar Englund
www.gke.org
--------------------------------------
100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...