overload ptc relay

[johnnicinco]

I have a refrigerator that is having compressor start problems. I measured the windings and the two separate windings don' add up to the total I measure for both in series. Can I assume that this means one of the windings is shorting to the frame of the compressor? Can I then assume that since the compressor will start after waiting say 20 minutes that the refrigerator would still function if I could just put a small delay in the thermostat that tells it to wait 20 minutes before kicking in, so that the compressor will have less of a load on it? I suppose the reason it works after 20 minutes is because either the pressure is too high for the compressor to kick in, especially with the weakened winding or because the winding is still too hot from the last time it had been working and needs time to cool down so it won't draw as much current or is a combination of the two. What do you think about the idea?

[benijoseph]

dear joco,

your problem is not clear, check for amps?.or try to start comp directly with out rely then check amps then come to a conclusion.

regds,

[NoNickName]

The compressor is tripping on discharge temperature or winding temperature.
When compressor starts, the superheat is maximum, and therefore the highest power input at the highest suction superheat (or suction temperature) with consequent highest winding temperature.
Reduce suction superheat. I don't think it's a low insulation problem. If it was, then it should trip on magnetic protection, not on ptc protection.

[amerhvac]

Not shorting your Compressor

possible
1- Low Voltage.
2- High Temperature around Refrigerator.
3- Stuck compressor.

[tonyhavcr]

You can add a hard start & relay
http://www.grainger.com/Grainger/SUP...ntrols-_-4LWX4

It is not a fix but helps w/ low voltage and compressors that are in need of starting help they work But I'm not a fan I like to fix the problem not just hide them

[chilliwilly]

What readings are you getting for each winding? I know that you don't need me to tell you but don't forget that the start winding is a higher resistance than the main winding. If its a conventional split phase type and not a psc type.

Can you be more specific with your readings? There is a small possibillity that the start winding could've shorted onto the case and caused an overload. Have you tried an insulation test to verfy the state of the windings?

If you put a timer in series with the thermostat you will only allow the temperature inside the cabinet to creep above the set point when it calls for cooling. And it will just cycle out on overload just the same. Assuming its a cap feeder the pressure will be the same in the low and high side after a few minutes. So if its tripping due to a high head pressure, the cap must be slugged up. Which then is another story.

Like one of the other posts say wire the windings direct to the pot. ie neutral-common, live/hot-main, live/hot jumped off from main winding ready to touch onto start, plug in lead/cord then momentary flick the start winding and see if it starts.
If it does and sounds and runs healthy, the ptc is sh*gged, if it just hums the pots sh*gged.

[tudorice]

maybe the unit is undercharged and therefore the refrigerant isnt cooling the compressor as it should. I also had a similiar problem with a refrigerator for a samsung wine cooler.

[kooljt]

Nice job fellas