View Full Version : How much is a phase 3 convertor?

11-09-2007, 07:40 PM
I am looking to set up a small machine shop in my house, I need to get a phase 1 to phase 3 convertor, about how much should I be expecting to pay for one?


11-10-2007, 09:07 AM
The cost depends a lot on the horsepower of your machine. Ebay has lots of phase converters for sale. You need a realistic approximation of the true power draw of the machine including spindle, coolant pumps, and hydraulic pumps. So you might have a 5hp spindle but there's a 1hp coolant pump in the base and a hydraulic pump that uses 1hp. If you go too small on the converter, whenever you turn the coolant pump on, you can trip a circuit breaker.

Generally, the rotary phase converters are better than the static phase converts. Obviously, the rotary converters are also more expensive. Both my VMCs are running on rotary converters.

11-10-2007, 11:11 AM
so lets assume you need about an 8hp convertor... what should that run you? I'm just trying to get a simple idea here so I know if this could even be doable for me.. otherwise I might have to look into 220v machines instead..

11-10-2007, 12:31 PM
I bought a 15 HP rotary phase converter for $900.

For CNC it has to be rotary, because it really delivers the third phase. The static converter uses capacitors to "fools" the electric equipment to think they have 3 phases.
The static converters work fine only with conventional non CNC machines.

Also, your converter capacity must be at least double of your machine requirement, if you have a 5 hp machine, then you have to buy the converter with 10 HP. That is because in CNC you normally do tasks that take a lot of power for short periods, like suddenly inverting spindle rotation for tapping, and full axis acellerations.

11-10-2007, 01:54 PM
Have you considered talking to the power company and getting 3 phase brought into the property, short of that get a GX390 with a 3 phase generator, should be good for 7-8 KW and portable, sort of.

11-10-2007, 01:58 PM
There has been past articles here about building your own & tuning etc, I built a 7.5hp rpc for $200.00, often 220v 3ph motors can be had cheap due to lower demand.

11-10-2007, 02:39 PM
Actual cost can vary. Ebay lists several 10hp converters for $500. However, some do require an external switch to power them up. Others have the switch integral to the converter.

11-20-2007, 07:49 PM
I would recommend American Rotary phase converters. It's the Gentec and Baldor company. Here is the link.
We bought one for our Hurco CNC, worked great. Easy to install, excellent packing, great bang for the back, excellent customer service, fairly quiet (more quiet than Phase o matic), pretty stout, etc. I can go on but you get the idea. One thing I feel it lacks or should improve on is a finer net/shield to protect the phase converter. Although I did read it had sealed bearings and capacitors. Hope this helped. I also received a couple positive reviews on the AR phase converters.