Fans On Single Phase Motors

Single phase refrigeration fans are simple.

The primary electrical problems I've encountered, are caused by capacitors.

All of the single phase motors I use are PSC motors. They all use run capacitors.

These capacitors display some unique characteristics.

Understanding these, can cut short the amount of time spent trying to repair the refrigeration system.

What's the second most common problem?


Most smaller inexpensive motors use sleeve bearings.

They are cheaper than ball bearings, but they also fail more often.

As to oiling them after failure, I refer you to the the following link.

Whenever possible, I always use ball bearings.

They last much longer.

When replacing the motor, try to match the replacement.

What do I mean?

Use the same voltage, rpm, frame size and horsepower, when possible.

Voltage is nonnegotiable. It must be the same.

Rpm is also nonnegotiable. Each motor is specifically designed to move a certain volume of air.

The frame size depends. It depends upon the method of mounting the motor. Sometimes the physical size of the motor is not important.

What about horsepower (hp)?

You can go above the stated hp rating of the existing motor, but never below.

If you install a motor with a smaller hp rating, it will pull too many amps, overheat, and eventually stop.

That makes sense.

Oversizing the hp is a waste of energy.

The motor uses almost as much electricity, even though the load is smaller.

Bottom line?

Whenever possible, I use OEM motors for the fans.

What is OEM?

OEM is the original equipment manufacturer's motor.

They are almost always more expensive.

But returning the refrigeration equipment to the original engineered specifications is worth the extra cost.

Besides, all the holes match up!

Keep life simple! That's my motto.

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