What's new
What's new

Which one of these 3-Phase and Transformer combination options is standard practice?

Spud

Diamond
Joined
Jan 12, 2006
Location
Brookfield, Wisconsin
Which one of these 3-Phase conv. & Transformer combination is standard practice?

A or B ? Does it matter? Are both ok, but is one better than the other ?



3-Phase-options.png
 
Neither is perfect but both can work OK.

Option A requires the digital phase converter to be derated so it can run on single phase input. Bigger converter will cost more.

Option B needs a 3 phase transformer which will be more costly. If using the phase converter for variable speed control there may be issues with transformer performance when running at different frequencies.

For motor drive best option is always to convert motors from 440 V star to 220 V delta.

I've never managed to make the finances of transformers for this sort of thing work out for machine drive. Even if you have to change motors its usually cheaper.

(I have a compressor with a 380 - 400 volt delta connected motor to hook up later this year. Plan A is to run it from a 220 volt VFD at 29 Hz which will give full torque but only a little over 1/2 output if thats not enough I can probably get up to around 3/4 output by tweaking the frequency. Motor change is last resort. Still cheaper than transformers.)

Clive
 
Neither is perfect but both can work OK.

Option A requires the digital phase converter to be derated so it can run on single phase input. Bigger converter will cost more.

Option B needs a 3 phase transformer which will be more costly. If using the phase converter for variable speed control there may be issues with transformer performance when running at different frequencies.

For motor drive best option is always to convert motors from 440 V star to 220 V delta.

I've never managed to make the finances of transformers for this sort of thing work out for machine drive. Even if you have to change motors its usually cheaper.

(I have a compressor with a 380 - 400 volt delta connected motor to hook up later this year. Plan A is to run it from a 220 volt VFD at 29 Hz which will give full torque but only a little over 1/2 output if thats not enough I can probably get up to around 3/4 output by tweaking the frequency. Motor change is last resort. Still cheaper than transformers.)

Clive


All of my equipment is 480v 3-phase. I don't want to change motors, too much of a hassle and expense. And some of my equipment is 3-Phase steam cleaners. I think I do have one or two 240v 3-phase machines.

In Option A, the digital converter is factory built to accept 440v single phase input.

So for people who won't change out motors, do they go with a 220v single-phase to 220v 3-phase digital phase converter or do they go with a 440v single-phase to 440v 3-phase converter ?

One transformer would be much cheaper and less hassle than changing motors. I am also not looking at rotary phase converters.
 
A or B ? Does it matter? Are both ok, but is one better than the other ?



3-Phase-options.png

B is most common and easiest.

mine it set up phase converter first. then have a branch that goes to a 240V 3 phase outlet, the other goes to a disconnect to the transformer and step up to 600V from there. that way you can step it up to anything after. 380, 440, 575/600V etc just with a used transformer that are a dime a dozen. got the whole works for $500 for mine.
 
"B" is what Phase-Perfect publishes right in their manual for 240 VAC single-phase input units for either of step-up or - in my case, Delta off the Phase-Perfect to Wye for a re-derived "neutral" to the load center, same voltage.

Any other digital phase converter probably has similar info in THEIR manual.

I could be worng, but AFAICS, used-but-good 3-Phase transformers are more easily found, cheaply, in the sort of KVA ratings you'd probably want than used single-phase.

NB: shipping the heavy buggers (27 KVA EGS/Hevi-Duty) can cost yah serious coin!
 








 
Back
Top