Refrigeration Compressors Need Adjustment?
Grab Your Sledgehammer!

Refrigeration compressors sometimes need very small precise adjustments. Have you ever used a 20 pound sledgehammer?

Am I serious?? You bet I am. I've used a 20 pound sledgehammer many times. It is one of the final steps in a process that demands exact precision measurements!

Measurements with a maximum allowed tolerance of two thousandths of an inch.!!!

Got your curiosity up? Read on!

One produce cooler I maintain has four Carrier 5H open direct-drive refrigeration compressors. Each one is coupled to a 100 hp motor.

They are not belt driven. The are not semi-hermetics, with internal motors. The compressor and motor are simply connected shaft to shaft.

Needless to say, the motor shaft and the compressor shaft must be in perfect alignment. The slightest misalignment can be disastrous.

I've seen entire condensing units vibrate and shake!

Not a good situation.

The shaking and vibrating destroys the coupling, wears out the compressor shaft seals, causes pressure control cap tubes to snap off, and eventually breaks or cracks refrigerant lines!!!

Aligning a direct-drive compressor is an art. Some technicians find it easy, while others pull their hair out.

You must use a dial indicator with thousandth of an inch increments. You also need precise shims.

The first time I replaced one of the 100 hp motors, I had a problem.The top to bottom and side to side alignment were almost perfect. But the motor was slightly off angle to the compressor.

Once before I had faced the same situation. When I loosened the bolts for a slight angle adjustment, I lost the top to bottom and side to side alignments.

How could I make the motor move just a tiny small distance while still bolted down???

By now you know where I'm going. In comes the 20 pound sledgehammer!!!

Believe it or not, a solid blow with the sledgehammer can create measurable movement on the dial indicator.

Need more movement? Hit the motor base again. Whoops, too much? Go on the other side and bang it back.

Keep going until you get it just right!!!

Amazing but true. Measuring one thousandth of an inch movements with each 20 pound sledgehammer blow!!!

Come to think of it, it must be quiet a sight. Precision dial indicator in left hand, 20 pound sledgehammer in right, time to go to work on those refrigeration compressors!!!

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