A/C Compressor coil burnt up?


The outside A/C condensor unit (Trane TTJ type) of my home has a
CSR-type compressor. It has two phase 120VAC fed to it. When the
thermostat calls for cooling, the fan runs but not the compressor, even
after it has rested for 24 hours. The A/C ran last summer. I just bought
the house last year so I don't know the history of the unit or its
maintenance.

There is a run capacitor across the S and R terminals of the
compressor. No start capacitor. This is a permanent split capacitor
type hookup where both run capacitor and start winding stay in the
circuit during start and after the motor is up to speed...

The resistance between the C and R terminals is 2 ohms. The resistance
across the S - R terminals (and the run cap) is between 1-4 megohms. I
take it this means my run cap is not shorted. Based on the high
resistance, is the S terminal open or the start coil burned up? If the
start coil is burned up, is there any way to start the motor using the
run coil and some external whizardry?

See figure 4-13 of http://www.tpc-nacg.com/servicehandbook.pdf where
the start winding has a series resistor...maybe its in case the run
capacitor shorts it would cause the thermal protector to trip...
protecting the start coil? The C terminal has an internal thermal
overload to protect the run coil.

There is no (apparant to me) low-pressure cutoff switch on the unit.

I took the cap off the freon return line and pressed the valve, there
is at least some freon in the system but I don't have gauges to see how
much pressure.


--
gado
.

Relevant Pages

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