Compressor or PTC

I've only been learning about refrigeration stuff for about a day so please bear with me.

My whirlpool fridge kicked the bucket a few days ago. The fan stays on but the compressor dies a few seconds after starting each time. It continues to cycle but same happens. Doesn't make any difference if I switch it off for a few hours. The compressor is not even heating up.

It has 2 model numbers on different stickers:
WRN28NWB6 and BG348W-Q-WPLAU
Compressor model: Samsung D162Q-L1Z
240v

Trouble is I've done all the tests that are written about on the web and I'm getting results that point to both compressor and PTC from my amateur interpretation.

The ground is ok on all three compressor terminals. The resistances don't add up though:
S-C 15.5 ohm
M-C 9.3 ohm
M-S 11.5 ohm

I presume M is run but even those numbers don't look right. The PTC attaches the bottom two pins which is marked M and S. From what I've read the highest resistance should be between those two.

The PTC measures about 30 ohms cold. I've opened it and the disc inside is intact and looks shiny and new. However I tried the lightbulb test. It took about 20-30 seconds before the light went out.

Possibly the way I wired it? I only had a 40w bulb in a lamp that I could cut the wires on. So to beef it up I hooked another lamp with 2 * 50w bulbs by attaching alligator clips to wires and then to the pins on 100w lamp plug. Had limited stuff so it was the best I could manage. It looks sorta like this:

L---|--40w----|
|--100w---|
|
PTC---N

Now I guess since the lamps are in parallel I'm not getting the 140w I was hoping for. But I'm not 100% sure on how to measure what it was. If I use the 40w lamp on it's own the light stays on (I stopped waiting after a few minutes).

Any pointers would be most welcome. I don't seem to able find much on the fridge model let alone parts. I'm a bit dubious about shelling out for a new PTC as those compressor reading are definitely way off the expected small + medium = big.

Oh I forgot to mention the overload is fine. 0 0hms. I've measured across it while it's running and it's definitely what's killing off the compressor so it's doing it's job.

Quote:

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Originally Posted by shadders

L---|--40w----|
|--100w---|
|
PTC---N

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That diagram didn't come out too well. The line connected the PTC should be coming out from the right hand side of the two lamps.

I think all the ptc does is disconnect the start winding once the comp is running, i expect you could replace it with a switch for testing purposes, on while starting and off after a second or two. Those compressor winding reading don't sound good, suspect the comp has died.

you say the overload is ok but all ur doing is proving continuity.is it weak? may be prematurely cutting out.have u clipped the starting current. to compare this with the locked rotor current.chances are ur compressor is siezing.

Quote:

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Originally Posted by install monkey

have u clipped the starting current. to compare this with the locked rotor current.chances are ur compressor is siezing.

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Not sure what you mean. I'm a total amateur. I see what you mean though, it's cutting out but not necessarily when it's supposed to?

So how would I check the starting current? Put my multimeter in between the the C pin and the overload and watch it at startup?

I just tried manually disconnecting the start after a second or so (using lots of rubber between me and the terminal). It still trips the overload. I actually noticed from being up close that the terminal on the overload gets red hot so I guess it's getting an awful lot of current. Perhaps to admit defeat and call the compressor bust. A shame, I liked that fridge and now my beer fridge is rammed full of unwelcome food items.

When you switch the fridge on and the compressor tries to start, open fridge door and see if light inside turns on/off by itself, or maybe the fan runs and switches off just before compressor tries to start.. Mike

I agree with monkey spanners comp shot