Compressor rotation

Sir,

Two winding in cap. start comp. so only change one winding terminal each-other (original is A1 - A2 now make it A2 - A1 ) than Your motor direction change

I doubt that you can change it because you probably do not have access to the internal winding connections. You did say that it was a sealed motor (didn't you).

Manufactures do not normally provide this connection for field changes because they do not want wiring errors in the field.

I don't know about yours, but many compressors are designed to rotate only one direction. Switch the rotation and you are likely to destroy it very rapidly.

If you are trying to make a heat pump out of a refrigerator, there may be a lot more involved...

I am interested in why you want to reverse the rotation? It will not work any differently.

So am I, so please tell us as there is no good engineering reason to do this, unless you want to just turn it into a pile of junk. A big hammer will do it as well.....

The motor is a single phase motor and rotation is determined by a shaded pole, thus the rotation cannot be changed. And its a good thing too, running the compressor backward would slug liquid refergerant into the cylinder and blow the compressor.

If you are interested in using the refrigeration system as a "heat pump", you do this by interchanging the evaporator and condenser coil connections by using a 4-way valve manifold. The refrigerant circulates through the compressor in the proper direction in either heating or cooling mode.

He said it was a cap start, not shaded pole. But other than that, you're right. The motor would run the same direction on a heat pump regardless of heating or cooling.

Perhaps he was thinking of using his refrigerator to generate electricity by filling it with dry ice and allowing the reverse flow of coolant to spin the motor?

OOPS ! My error.thnx.............

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When I ponder, I sits and thinks, sometimes I just sits.......

If the following is true, the rotation of a single phase motor can be changed (the probable consequences of which need not be covered further!):-

1) Both Field windings easily accessible and it must be known exactly which field has which connection. No "ifs", "buts" or "maybe".......

2) Capacitor starting.

Then swapping one field's connections around will cause the motor to start and run in the opposite direction. It does not matter whether its the field with or the field without the cap...

Remember, swapping both just means it continues to run in the same direction as before!!!

Follow all normal safety precautions to make sure that nobody gets electrocuted....

The big "if" is in getting access to the wiring. Most sealed compressors don't allow it.

You are of course dead right, my answer was more based on theory that actual practise!!

I have a test instrment made by gould its called annie and it could allow me to test compressor wone of the things it did was rock a tight compressor it does this by changing the direction was just trying to see if i could repair this test equp there wiring digram not avable any more or inst so that was the reason for my question so thank for all the help..

cliffside

It seems several of you are assuming that he is trying to create a heat pump.

I did not see that in his question?

Mr OLDF**T has explained how a heat pump is design, by reversing the flow and control device.

So what is the reason or thinking in reversing the rotation.

A reciprocating hermetic compressor has reed valves and the oil is circulated via the refrigerant. The compressor will perform the same, regadless the rotation.

A scroll type compressor is something all together different. It must rotation in the proper direction, and you know immediately if it is not in the proper rotation.

I'm afraid we have oversimplified the compressor reversal question, particularly if we are considering a reciprocating refrigeration compressor, hermetic, etc. If the rotation of the compressor is reversed, not only will the system fail to operate properly, but the compressor would probably destroy itself.

Considering the system - refrigerant circuit - walk through the sequence and you will see that the expansion valve sensing element is on the wrong side of the evaporator coil, which is now the condensing coil (in the reversed flow), with hot gas temperature sensed by the element, the expansion valve would go full open, etc.....

However, the compressor itself will not function in reverse, because the suction line attaches to the compressor through a fitting that incorporates the crankcase such that the entrained oil is allowed to drain into the crankcase, and allowing the suction gas to enter the compressor through the open suction valve.

There are compressors which utilize an oil seperator in the discharge - high side - line ahead of the condenser, which returns the oil directly to the crankcase. Screw machines are notorious for slugging oil. Some now have the oil seperator built into the compressor.

g scott

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When I ponder, I sits and thinks, sometimes I just sits.

What is your reason for wanting to reverse the compressor rotation?????

Another one scared off by logic and reason...

???????

I have the feeling that he thought that by reversing the motor, he could reverse the process in some way.

This type of "reverse-thinking" is sadly typical of quite a lot of CR4 questioners, because to do what they want to do, they do not have even the start of the background knowledge needed........

.......which is why they come to CR4 in the first place, but of course the answer they read from us then blows their dreams to pieces!

I find it sad, that their background does not even allow them the smallest inkling to be able to see that it does work like that, that there would appear to be major errors in the way people are educated in schools and colleges......this has been stated in various ways on various postings on CR4 lately......sad really......and we burst the dream Bubble!

I'm putting a new electric motor on an old upright Curtis stationary air compressor but I'm unsure of the proper rotation, clockwise or counter clockwise. Will it function in either direction? How do I know if it's going the correct direction? I don't want to find out the hard way, if you know what I mean. Thanks.