Setting Up Three-Phase Power

Owners share advice on ways to upgrade the shop's power supply. June 12, 2005

I have recently acquired a planer, jointer, and band saw that all have a 3 phase motor. I am planning on building a shop on my land, and am left with 3 options and would be interested in others opinions. The options are to:

1. Try to get the power company to pull 3 phase lines to my shop (3 phase runs in front of my house).

2. Change out the motors to single phase.

3. Use a phase converter.

Which is the easiest and cheapest?

Forum Responses
(Cabinetmaking Forum)
From contributor R:
I went through this a few years back when I bought my first Bander. I never considered changing out the motors as an option. The power company wanted $8,000 to get a 3 phase to my shop and I was still going to have to pay an electrician to get the 3 phase into the shop, so I was looking at well beyond $10K.

It was a simple decision to go with a 15 horse-power rotary converter which cost $1,500. The electrician charged me $500 to install it with one outlet. If you go with the converter, go with the biggest you can afford. I should have looked into a 20 horse power converter.

From contributor L:

I've been using all methods of phase conversion for 25 years, and in a nutshell, the answer for your application is clearly a rotary converter. A static will run about $200 and you can buy a used three phase motor for cheap, if you look around.

From contributor J:
I would not make this decision until after you talk to the power company. I faced the same situation with a three phase in front of my house. After I provided a list of equipment that I would be running, they ran the three phase power overhead for no charge. I had 400 amp service brought in and it cost about $6000 for wiring up my shop. This included a 400 amp three phase panel with breakers. A 200 amp panel was about a third of the price.

I have also used rotary converters and they do work ok, but they aren’t as nice as the real thing. If you buy any new equipment like a edgebander, widebelt sander, CNC, etc., phase converters can cause you problems with warranties. All this type of equipment requires all legs of the power to be balanced. I'm not saying you can't do it, but it often requires buck boosters to go with your converter.

From contributor P:
I built my shop last year, and didn't even waste a call to the power company - they'd want more than the price of the converter just to engineer and estimate the extra lines. A 20 horse-power Gentec was simple to install, inexpensive, lives in the basement, runs everything, and is trouble free and quiet.

From contributor B:
As one who may move his shop from a 3ph to 1ph, does each piece of equipment have to have its own converter? Can you run multiple pieces of equipment at the same time?

From contributor P:
To contributor B: One big phase converter, powered from your single-phase source, provides current to a three-phase panel which then provides separate circuits to the machines you want to run on it.

From contributor A:
You should talk to the power company first. If there is 3 phase power going past your shop, the power company may only charge you for a transformer. Or as someone has already said, they may charge you nothing if they think the revenue warrants it.

I have used a rotary converter for 6 years with no problems, but if I add the new wide belt I am going to have to make major additions. All in all, if you can get a 3-phase from the power company, you will be better off over the long haul.

The comments below were added after this Forum discussion was archived as a Knowledge Base article (add your comment).

Comment from contributor O:
When I showed the power company how much load would be dumped on their line for new single phase equipment, they decided it would be better for them if we bought three phase and they ran the lines to the shop at their expense.