Phase Converters for a Small Shop

Downsizing from a big-iron shop to a basement-based setup. Is it worth holding on to some three-phase machinery and installing a phase converter? April 27, 2011

Question
I may be forced to abandon my current shop due to the economic meltdown. I will probably liquidate all my 3-phase machines (slider saw, 24" planer, 16" jointer, 52" widebelt, 9hp shaper, 5hp compressor, and Powermatic 66 saw).

At the same time, I'm looking down the road and will somehow rebound with a smaller home-based shop setup. Assuming I have a 200 amp typical home electrical service, with a sub-panel for the shop, is it worth keeping a couple of these good machines (like the Powermatic saw and the Oliver 16" jointer - the others are likely too big) and running them with a transformer? Or would it make better sense to just replace all with single-phase equipment? Put another way, is it practical to run a few 3-phase machines, say 5hp each, using a transformer in a home shop with a 200 amp house service, along with several single-phase machines? How much does the appropriate transformer cost, and is the wiring to machines any trickier (I would hire an electrician regardless for this)?

Forum Responses
(Dust Collection Forum)
From contributor K:
You can get a good quality rotary phase converter from American Rotary in Wisconsin for a reasonable price. I bought a 25 hp converter about 1 year ago for about $1300.00. Any good electrician will have no problem installing the converter and the circuits, however the disconnect switch, the power switch, the service panel and the electrician's labor for installing all of that plus a circuit for an edgebander and a circuit for a boring machine cost more than the phase converter ($1700.00). If you can get by with a smaller converter and run some of the circuits yourself, you can save some money. I highly recommend American Rotary if you decide to purchase a converter.


From contributor J:
There are a lot of variables at play and a lot will be based on what you can fit. My opinion is that the more of your bigger equipment you can keep, the better off you are. First off you already own it, so no need to sell and start looking for a replacement. Second your 3 phase equipment is going to be generally better quality than new single phase equipment.

Of course some of it will be too big and need to be replaced, but I would hold on to anything I could shoehorn into your home shop. Also remember that you may be able to swap motors and electrical in some of your equipment. The 66, for instance, and if the Oliver isn't direct drive, that also.

You may want to spend a little time over at the old woodworking machinery site, as they have a lot of discussions on 3 phase equipment and converters. You can ask the guys their opinions, as many are doing what you describe.


From contributor U:
You need a phase converter (rotary or static) or several variable frequency drives (VFDs). Transformers convert voltage (like 230 to 460), but not phase. I used a static converter (basically a motor starter) in my garage shop for several years. You give up 1/3 of your power, but they do work and are inexpensive. If you have several motors of the same HP, you can run them all off the same static converter. Rotary converters cost more, but you have full power of all 3 legs of the 3 phase. Sorry to hear about your downsize. Hope you find a new balance that works out.

From the original questioner:
Thanks for the info. Regarding potential shop closure, as a wise man related to me in a different setting: "Where a line ends, a circle begins."

From contributor C:
Phase Perfect brand converters can deliver better and more accurate power than what the power company supplies. This, according to what a friend of mine says, using one in a home shop with a lot of heavy duty machines. He is even running a medium size CNC router with it. They are expensive.
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