ECN Forum Forums Technical Discussion Electrical Theory and Applications Single Phase to Three Phase Conversion

I really only need a converter (from 240V 1-PH power to 208V 3-PH power). A VFD can do so much more than convert 1-PH 60 Hz to 3-PH 60 Hz power, but I have no intent to soft-start (ramp up) the pump or to slow the motor down in this application. Do you have any recommendations as to what type converter to use?

[Isn't an inverter changing DC to AC, and a power supply changing AC to DC?]


[This message has been edited by FountainGuy (edited 03-23-2006).]

The inverter does as you say but a power supply might be just about anything. Inverters would be a subset of power supplies. I did a Google search of "3 phase converters" http://www.phaseperfect.com/ looks somewhat interesting. It looks like most of the static converters out there only produce the third leg. The only 3-phase inverter that I have worked on is made by Trace. It has a 600V input. If you do that search, you will find alot of info on your choices that wouldn't have shown up on a search for VFDs. Good Luck,
Joe

Thanks for the phase converter link; I'll ask for their input today.

I had one vender research all of my options, which include an add-a-phase transformer, a soft-start unit, and a VFD. His results brought him back to the VFD. It looks like the Yaskawa brand is the most economical approach; it's smaller than I thought it would be at 21" tall x 10" wide x 10.25" deep.

One vendor said that I needed line reactors because of the single-phase input, but my best vendor source said that line reactors are only necessary if the power line is dirty or if the power is a very long run.

I only got one price for a 15HP 1-Ph pump, two pump vendors are still looking and three other pump vendors said that there's no such motor for a close-coupled end-suction pump, that 15HP 1-Ph motors are only available for submersible (turbine well) pumps.

P.S. I read the posts regarding adding a motor to covert to three-phase. If this application were for me personally, and if I had the space, I might pursue this option. The 15HP pump will be in a fiberglass underground vault that is about 5'-7" x 6'-4" in plan view. This is for a fountain with off/on controls by a simple digital timer. This fountain will probably (hopefully) be visited by the maintenance guy once or twice a week.

[This message has been edited by FountainGuy (edited 03-24-2006).]