Three phase generator

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Running machinery off of a three-phase generator. September 2, 2002

I am scouting out locations to move all my machinery to. Iíve moved it all out of the old place, except the moulder. Iím interested in hearing about different types of machinery bases, especially wood.

Also, I have the opportunity to purchase land on the cheap without dedicated 3 phase lines. I am interested in hearing from someone who has run with a generator and a dedicated service. What are the pitfalls of a standalone generator?

Forum Responses
Almost for sure, you would be better off buying a bigger electrical service and a phase converter.

I run a 175 kVa 3 phase generator. It has a Volvo motor and Rockwell gen. I wouldn't go to anything lso. Electrical service here is expensive and unreliable. When I looked into installing 3 phase from the road, it would have cost me $20,000 and I would have had a minimum bill of $600. The lines had to go 5 miles. Also, right now I only run the sawmill, but they also said I would have to sign an agreement that if I added more than three motors, I would start them at half hour intervals (otherwise the whole town would die down). Your situation may be different from mine, since I live in Bliss, population 50 people, 5000 cows.

The biggest pitfall is the added machine to maintain. It costs me about $200 every 6-10 weeks. Sound isn't too much of an issue. I have it in an enclosed trailer body with the exhaust piped out the side and heat vents moving the air. It is 150 feet from the house, and I can come in, shut the door and not hear it. Volvo is a considerably quiet motor, though. Nothing like a detroit.

Also, my mill is on a wood floor. There are railroad ties every 4 feet and 2x8 floor joists every 2 feet crossing the railroad ties. Then I have ash 6/4 flooring. I hate it. I can't wait to get a concrete floor. The mill does a good job supporting a log, but the floor doesn't. You can see on my floor where it has collapsed. I slid a 2.5' I beam, laying on its side, down the center of the mill. Now all my supports are on the I beam, and that disperses the weight better.

I have a 90kva gen set with a detroit. I put it in a box off a truck behind my mill building and at about 100 yards you can hardly hear it. If I had this to do again, I would do it the same way only with a much bigger gen set. They wanted 12,000 to run a line about 300 yards and $500 a month usage and I would have to give a small plot of land for a 3 phase sub station. 12 grand would buy a good gen set and Iím sure it wonít burn $500 in fuel a month. If this land is cheap and buildable and away from everybody, so you don't have complaints, go for it.

My vote would be for the biggest 3 phase generator I could find. Phase converters are okay for smaller operations, but they have to make up a ghost phase to make the motors think they have 3 phase power and are not as powerful as the real thing.

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

Comment from contributor A:
You should consider a solid state three phase converter from Phase Technologies. These devices can supply three phase power for your entire shop. They supply units from 10hp to 30hp. Unlike rotary converters they have no minimum load requirement, can maintain balanced voltage on all three phases and do not have to be oversized to handle starting currents. A 10hp converter can start a 10hp motor. They can run any number of loads simultaneously, or for a single load can utilize built-in starting and protection circuits. I have the 10hp unit and run a 9hp bandsaw and 8.5hp sliding table saw with excellent results.