- Joined
- Jan 8, 2020
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- 176
The guy selling this says it turns 208v to 480v but isn't this tag saying it makes 480v into 208v?
View attachment 325777
In theory (and usually in practice as well) you can run a transformer backwards, feeding the secondary and taking the output from the primary.
However, feeding 220 (or 230 or 240) volts into a 208V winding will at a minimum make the transformer run hot. Worst case it runs so hot that it burns up. And since you are feeding 220 into a 208 winding, you'll get something like 508 volts out of the 480 winding.
Next problem: you didn't mention how big the motor that you are trying to run is. That transformer is huge - 45kVA could run something like a 50HP motor when used as intended. Because it is a big transformer it will have big inrush current (tripping the 220V breaker), and draw a lot of no-load current. Not good.
A further complication (and this is the real show-stopper): That transformer is three phase. You have one phase power. You can't feed a three-phase transformer with single phase power. Period. Done. Do not pass go.
In theory you could use a VFD to convert your 220 single phase into 0-208V three phase, then the transformer could step it up to 480 three phase for the motor. In theory. I'm an electrical engineer and spent most of my career designing VFDs, and I would try to find another way before I tried using the transformer on the VFD output. Just too many ways it could go wrong. For someone unfamiliar with the technology I wouldn't touch it with a ten foot pole. And the fact that the transformer is still way over-sized makes it worse.
You want a single phase 240-480 transformer. And not 45 kVA.
You didn't mention the size of the motor you are trying to run. If it's a typical Bridgeport or similar 1-1/2 to 3 HP motor, you could use about a 5kVA to 7.5kVA transformer. Something like these:
Any of those would convert your 220 single phase to 440 single phase. Then use a 480V rated VFD to run the motor.