Using VFD on single phase source

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Besoeker

Senior Member
Location
UK
So Gar you are good with 1.5 factor?

Try this: 10a x100v 3ph produces 10x100x1.73=1730watts. Agree?

How many amps 1ph for same 1730 watts?

Still want to stick with 1.5?
It's 1730 VA, not Watts. But let that pass.
You cannot apply linear circuit analysis to non-linear circuits.
 

gar

Senior Member
Location
Ann Arbor, Michigan
Occupation
EE
170515-2332 EDT

mike_kilroy:

I said nothing about input power. I approximated the diode average current, and since diode voltage is approximately constant I can approximate total diode power dissipation that in turn approximates diode junction temperature rise.

If you want average input power in this application, then you need the instantaneous product of the input voltage and current, integrate this over an adequate time, and divide by that time.

The current waveform is not a sine wave, but a smooth rounded pulse with a slower rising slope than falling slope for a sample circuit I measured. Inductance is causing the rounding.

.
 

Besoeker

Senior Member
Location
UK
170515-2332 EDT

mike_kilroy:

I said nothing about input power. I approximated the diode average current, and since diode voltage is approximately constant I can approximate total diode power dissipation that in turn approximates diode junction temperature rise.

If you want average input power in this application, then you need the instantaneous product of the input voltage and current, integrate this over an adequate time, and divide by that time.

The current waveform is not a sine wave, but a smooth rounded pulse with a slower rising slope than falling slope for a sample circuit I measured. Inductance is causing the rounding.

Something like a single phase version of this?

Idiscontinuous_zps1dc92984.jpg
 
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