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#129204 10/21/04 10:38 PM
Joined: Oct 2004
Posts: 2
Junior Member
I’m a novice electrician looking for some help on phase conversions. My small wood shop at home has only single phase service. I am looking at purchasing some woodworking machinery that requires three phase to operate. I’ve talked with my power company and three phase is not available at the street and would be very expensive to make available. I’m interested to find out what my options are as far as getting phase converters. Also what would be most efficient and cost effective? I’d appreciate any help. Thanks

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#129205 10/22/04 04:51 PM
Joined: Sep 2001
Posts: 806
It all depends on what the machines are, how big the motors are, and how much you want to spend. Options are:

Static Converter--cheap, but will not run or start large motors very well.

Rotary Converter--More expensive, and somewhat noisy. Works well with most loads.

Solid State VFD--installed on each machine, some models can generate 3 phase out from single phase power. Also gives you the ability to vary the motor speed.

Motor Replacement--if the motors are small enough, and standard frames, swapping them for single phase motors is always an option.

#129206 10/22/04 05:09 PM
Joined: Mar 2004
Posts: 947
twh Offline
I worked with a few static phase converters on oil wells. They ran 20 hp to 40 hp motors, started reasonable well and handled a load fluctuation of 50% fla to 125% fla (approx). The motor capacity is reduced by about a third and it can be a pain to balance the phases.

I'm comfortable with them on motors of that size, but I'm not sure about larger or smaller.

#129207 10/25/04 12:06 AM
Joined: Oct 2004
Posts: 2
Junior Member
Thanks for the replies.

From all the research I've done on the internet it seams like the Rotary Phase converter is more popular. One company in particular that I have found online ( offers a rotary phase converter for a reasonable price. If possible I'd like to know what you think of their product.
Motor replacement is not an option. It would be very expensive.
I will be running motors up to 20HP and more than likely will only be running one machine at a time.
One of my tools in particular has two motors. One main motor 18HP and an accessory drive motor that’s 2HP. Does having two motors on one machine make a difference? Which of the converters will give max output power?

#129208 10/25/04 07:45 AM
Joined: May 2002
Posts: 25
I've worked with Gentec before on a lift-station pump upgrade. Contact them with the motor nameplate information and they will size the unit for you. They did a great job for us.

#129209 10/25/04 08:31 PM
Joined: Mar 2004
Posts: 947
twh Offline
Static converters must be sized differently for each motor. Rotary converters can run more than one motor.

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