Cap wires melted

[Mickvee]

Got called out to 2 LG B3660HL ceiling casette systems in the same building because of not cooling. I found that the run wires from the compressor to the capacitor was melted off at the cap end on both seperate units. Also across the cap is a P.T.C device, what is this for Before I replace the caps and wiring has anyone come across this before

[frank]

Any chance of a photo?

[phil68]

Got called out to 2 LG B3660HL ceiling casette systems in the same building because of not cooling. I found that the run wires from the compressor to the capacitor was melted off at the cap end on both seperate units. Also across the cap is a P.T.C device, what is this for Before I replace the caps and wiring has anyone come across this before

Is that device wired across the cap maybe a bleed resistor

[Mickvee]

PHTO0239.JPG

Any chance of a photo?

Here is a photo of the cap and P.T.C to its left.

[wambat]

Got called out to 2 LG B3660HL ceiling casette systems in the same building because of not cooling. I found that the run wires from the compressor to the capacitor was melted off at the cap end on both seperate units. Also across the cap is a P.T.C device, what is this for Before I replace the caps and wiring has anyone come across this before

PTC stands fo positive temperature coefficient and it's wired in series with the start winding and in parallel with the run capacitor it functions dusly: As voltage is applied to the run and start windings the PTC will have very low resistance ,so the current draw on the start winding will be high for a few seconds then the PTC will dramaticly increase it,s resistance and cut out the start winding and the compressor will run like a perminant split capacitor motor. The capacitor may have shorted out and taken the PTC with it. In any event make sure you check out the motor windings before you replace the components.

[Mickvee]

Thanks for that.
I have checked the comp with a megger and checked the windings resistants and checked out OK. I have an annie analyzer, so I will check if the compressors are jammed. How would you test an PTC

[Andy W]

LG again....aaaaaaaarrrrrrrrrrrrrrggggggggggghhhhhhh

[fixit]

Mickvee
Did you test the voltage on site?

[Mickvee]

Hi
Yes tested supply voltage and was within normal limits, but they have had power surge in the past. The cap tests open circuit, and is rated at 50uF & 370/400 VAC.