Single phase to three phase supply

[alfred75]

Hi guys!

I have a motor inverter for repair with input supply at 440VAC / 3 phase. But there's only a single phase 220VAC at my house. How can I make the conversion to three phase?

I came across with the phase converter or rotary converter at the net but I'm not very sure about it.

Thanks for your feedback!

[budm]

Re: Single phase to three phase supply

3-phase delta or wye?
But no matter what it is, it is not cheap and depend on VA requirement.

[bluto]

Re: Single phase to three phase supply

My friend built a converter to run a 3 phase radial arm saw. It used a 3 phase motor sitting on the floor to generate the third phase. A control box with a couple buttons and lights contained some capacitors and relays that when activated would approximate 3 phase for a few moments to get the motor turning. Once rotating, the winding of the third phase acted as a generator.

Here is some info: http://www.nojolt.com/how-to-build-a...onverter.shtml

[JayArr_BC]

Re: Single phase to three phase supply

Easiest way is to run a single phase motor connected by a belt to a three phase generator.

Trying to do it electronically costs a LOT of $$.

Here's an important question though. When the power enters your inverter does it go immediately to a three phase bridge and then to a set of capacitors? Does it get immediately converted to DC? (happens a lot if the unit is running a servo)

I've repaired quite a few three phase unitss that did this and if the initial stage just converts it to DC then all you really need is 440V. I take a transformer that'll accept 220V in and up to 560V out and connect the output ti L1 and L2 and ignore L3. The units will work but not at full load, I just test them with an unloaded motor.

JayArr

[alfred75]

Re: Single phase to three phase supply

JayArr, I think you just gave me a great idea about a step-up transformer. I'm gonna try it.

Thanks a lot!