Single Phase Compressor Connections

[Grizzly]

Have you ever wondered which way around the 3 connections go on a single phase Compressor Motor?

Open the attached and print of for a useful reminder.

See page 2 for diagram!
Cheers Grizzly

[taz24]

Nice one Grizzly..

taz

[Brian_UK]

And when using a multimeter....

For a single phase compressor your highest resistance reading between any two connection points should be found from the start (S) terminal to the run (R) terminal.

Once you determine where you get your highest
reading, this will identify the common (C) terminal as
the terminal you were not using when you found the
highest reading.

Write down or remember the highest reading value for the moment.

The next test will be from the common (C) terminal to each of the other two compressor terminals, S and R.

Whichever has the highest reading from the common (C) terminal will be the start (S) winding terminal and the lowest reading will be from the common (C) terminal to the run (R) terminal.

If the compressor windings are good the resistance values will add up correctly. For example, if the highest reading found was 10.5 ohms (S to R). Then the next highest reading was 8.4 (C to S), then the lowest would have to be 2.1 (C to R) for the compressor windings to be good. (C to S) + (C to R) =
(S to R) would indicate the compressor windings are
good for a single phase compressor.

Normally your readings may not be exact to the decimal point (your meter could round up or down the values) but should be really close if the compressor windings are good.