DC Motors and PFC
DC Motors and PFC
(OP)
Greetings,
I am trying to figure out the correct steps in applying PFC caps to some large DC motors. I would prefer to do this on the line side at the DC load as opposed to putting a large bank at the service entrance but was wondering at what level of harmonic distortion (both voltage and current) I would be required to use a filter in addition to the capacitor.
Also I would like to know at what degree harmonic a filter is absolutely required regardless of the amount of distortion.
Any input would be greatly appreciated.
Thanks
I am trying to figure out the correct steps in applying PFC caps to some large DC motors. I would prefer to do this on the line side at the DC load as opposed to putting a large bank at the service entrance but was wondering at what level of harmonic distortion (both voltage and current) I would be required to use a filter in addition to the capacitor.
Also I would like to know at what degree harmonic a filter is absolutely required regardless of the amount of distortion.
Any input would be greatly appreciated.
Thanks






RE: DC Motors and PFC
RE: DC Motors and PFC
RE: DC Motors and PFC
Thanks
RE: DC Motors and PFC
I would suspect, your low pf at the service is not due to DC drives..What is the average pf at the service?
RE: DC Motors and PFC
If I have to treat at the main service entrance I will but like I said I would like to treat at the load to mitigate the line losses as well.
RE: DC Motors and PFC
If you do have an older DC drive, the tricky thing is that the pf will vary with speed. Determine the lowest speed you will run the system most of the time, then measure the pf at that speed and correct for it to about .95 by looking at correction charts from the PFC mfgrs. But an engineered system that is also a harmonic filter is really the best solution, because as davidbeach said, you can run into resonnance problems putting caps in front of drives by themselves if you don't know what you are doing.
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