Single vs. three-phase motor
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Q: Would you happen to know the answer to this non-wood question? Given a choice of a single phase motor or 3-phase motor, which is best?

A: The Wood Doctor does indeed know the answer. No question about it...3-phase motors are better than identical horsepower single phase motors. Three-phase motors are smaller, less expensive (much less expensive often), have higher starting torque, are more efficient, use less current per phase, do not require a starting capacitor, and are easier to repair.

But here is the main concern...do you have 3-phase available? If available, then everything is positive for 3-phase motors, with no negative concerns. However, if 3-phase is not available on the lines outside your plant, it will often be extremely expensive to have the electric company bring 3-phase to your facility. It can be so expensive that it will be 10 years or longer before you can recover the costs through the savings of 3-phase motors. [Note: It is not easy to make 3-phase yourself from single phase line, although converters are available.]

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About the author
Gene Wengert

Gene Wengert, “The Wood Doctor” has been training people in efficient use of wood for 45 years. He is extension specialist emeritus at the University of Wisconsin-Madison.