[Governor]

Greetings from Australia.

I have a big old compressor, motor stopped running, so pulled it down and cleaned a ton of dust and insect nests out, windings all looked fine.

Run capacitor tested fine (uF test).

Start capacitor failed uF test - only showing around <1nF. Specs are 200-240uF.

I bought a replacement, but when testing the new cap, it also shows <1nF.

I did an Ohms test on both. Original cap starts with very low resistance but continues to increase over time. New cap shows open circuit.

All testing with the bleed resistor removed.

Confused by this, I decided to install the new cap anyway, using old 15K bleed resistor which tested fine, and the motor starts up and runs as normal.

Does anyone have a sound explanation for the <1nF reading on the good cap??

Scratching my head...

 

[Fishbulb28]

Does anyone have a sound explanation for the <1nF reading on the good cap??

That is standard behavior on some meters when measuring a cap out of the meter's range or simply not waiting long enough. What model were you using?