View Full Version : Static Phase converter?

01-10-2010, 12:33 PM
I have a 3HP mill that I am wiring up in my garage. I am thinking of buying a static phase converter to run it. Other than losing 1HP are there any other drawbacks to using one of these converters?

Donkey Hotey
01-10-2010, 01:20 PM
It's a manual machine, right (not a CNC)? Nope, it should work fine.

01-10-2010, 01:48 PM
actually it is a cnc conversion but my motor is 18 years old and not inverter duty.

01-10-2010, 02:00 PM

If your machine is CNC then the static phase converter will not do the job, your spindle drive motor does not have to be inverter duty to use a VFD to drive it

Donkey Hotey
01-10-2010, 02:04 PM
If it's a CNC conversion, all bets are off. It'll depend on how everything is wired and exactly what the power requirements of each part of the conversion are. If the spindle isn't controlled by the computer and the rest of the conversion is 115V, you might get away with it. Too many variables to make a decision via the web.

01-10-2010, 06:57 PM
Use a VFD, rather than static convertor, you will have the advantage of variable speed, most likely the only thing 3 phase is the spindle motor, if so, then feed the rest of the control off 120v or 240v 1ph as required.

01-10-2010, 10:36 PM
If you have a 220 volt 3phase inverter with a 40 amp input rating, Does each wire of the input need to be rated at 40 amps or is that the total average amps of all 3 wires ?

How do they rate the current on each wire of a 3phase compared to if the inverter was Single phase input with a 40 amp rating ?


01-10-2010, 11:55 PM
If you have a VFD rated at 40amps each of the 3 phase conductors has to be rated for this amperage, as does the single phase conductors.
In the 3 phase supply, each conductor will at some point have to carry 40amps.
However the VFD is fed, the maximum current through the VFD should not exceed 40amps in this case.
When used on 1 phase, de-rating has to be taken into account on some models due to single phase rectifications being much less efficient than three phase.