[daniel w]

I posted a prior post ( Whirpool fridge/freezer not cooling at all) on 3-19-08. I have since performed testing and would like to share my results with others who may have similar issues. I would also like to get a couple of my questions answered.

Test results:
I removed the relay/overload/start cap and ohmed the compressor windings. The results for the three terminals were:
+ Top front to bottom terminals = 3.4 ohms
+ Top rear to bottom terminals = 6.8 ohms
+ Top front to top rear terminals = 10.2 ohms
All three terminals were open to ground.

Do the ohm readings above indicate bottom is common, top front is run, and top rear is start?

Next, I ohmed the relay on the bench. Results were open from each top terminal to bottom terminal, 5 ohms between two top terminals.
Next, I connected the relay power (normal fridge plug) and put fridge in service mode that runs compressor. Upon entering this mode, condensor fan ran normal and I checked voltage from each top terminal of relay to the bottom terminal. Voltage (128 VAC) was measured between bottom terminal and each of top terminals as long as fridge was in this mode.

If my guess at the windings is correct, then this indicates voltage on both start and run windings at the same time. It seemss this would trip overload. This could explain why my compressor shuts off after approx. 5 seconds.

I would like to know if someone can confirm my understanding of which winding is run and start as explained above. Also, do my relay test results above seem to indicate a bad relay.

I'm an electrical engineer with lots of field experience; however, I wanted to get an opinion from someone who is more knowledgable about fridge systems.

Thanks in advance for the help! These forums are a great service!

Best regards,
Daniel

[daniel w]

I purchased and installed a new relay/overload today. Now, my fridge/freezer is back to normal cooling. Thought I'd post this follow-up in case someone else has similar symptoms.

Upon buying the new relay, I tested it with an ohm meter. It was open between bottom terminal and each of top terminals. I read approx. 15 Mega-ohms between two top terminals (run and start coil terminals). The old relay had only 5 ohms between two top terminals. This confirmed my suspicion of a bad relay that was causing both start and run coils to engage at the same time, thereby tripping the overload after approx. 5 seconds.

My email above has info. about ohm readings for my compressor and how I determined which compressor terminals were start, run, and common. They were as I had believed in my post above. You ohm readings my be slightly different; however, the start coil is often approx. double the resistance of the run coil. The ohm readings for other compressors are likely in the same range as mine. An extremely high ohm reading or open circuit across either coil would be a problem. Also, be sure to check each pin of the compressor to a good ground on the unit. A grounded compressor terminal is a problem, since it indicates a path for power to short-circuit the compressor windings.

Hope this info is helpful to others.

Daniel