Anyone have troubleshooting knowledge of refrigerators?

[llonen]

Re: Anyone have troubleshooting knowledge of refrigerators?

I service and repair fridges, typically the ones I look have two winding's a start winding and a run winding, a PTC (positive coefficient thermal) device presents a low resistance typically between 5 and 15 ohms depending on spec at start. Both start and run wingdings are energised during initial start, the start winding load causes the ptc to change its resistance with temp disconnecting the start winding.

[caphair]

Re: Anyone have troubleshooting knowledge of refrigerators?

I service and repair fridges, typically the ones I look have two winding's a start winding and a run winding, a PTC (positive coefficient thermal) device presents a low resistance typically between 5 and 15 ohms depending on spec at start. Both start and run wingdings are energised during initial start, the start winding load causes the ptc to change its resistance with temp disconnecting the start winding.

Do you know what the circuit board in mine does? I understand the PTC device's role. Should there be 120v on both the start and run windings initially?

[caphair]

Re: Anyone have troubleshooting knowledge of refrigerators?

I have a friend that uses a fridge compressor to evacuate auto air conditioning, the oil is in the compressor and as long as you don't turn it upside down the oil stays in the compressor. He has been using it for years without a problem.
Check the internet for "make a fridge compressor into a vacuum pump"

if the short is only a couple windings the dc resistance will not change by much but the motor will not run.

check the run cap. it could be open but if the bi-metal over currrent is tripping I suspect the rotor is locked

Is the run cap disconnected once compressor started or stays in circuit and has no role in starting? What's confusing me is typical application of a start cap that's disconnected by the PTC when compressor starts. Are you suggesting the compressor isn't working thus the PTC cools, closing the start circuit and trying again? If so then I imagine the PTC stays open during normal operation as current is fed into the compressor.

Still confused about that circuit board's role though. Only thing I can think of is 120v is used to trigger the gate of the triac on/off as opposed to a little signal coming from somewhere else to the gate

[caphair]

Re: Anyone have troubleshooting knowledge of refrigerators?

Wait a minute. I think I'm getting lost in terminology.

Is the "overload protector" different than the "relay"?

If so then the circuit board would be the "relay" that gets the compressor started/running and the overload is separate and opens ONLY if the compressor draws too much current but otherwise stays closed allowing electricity through?

Here is the overload (left) which is connected in series with L and the circuit board "relay" on the right.

If so then the clicking I was hearing must be the overload. So maybe the compressor is shorted internally even though both start and run windings measure fine

[llonen]

Re: Anyone have troubleshooting knowledge of refrigerators?

Unless you are referring to a capacitor not shown in the pics, neither of the capacitor's on the board are motor start caps. The pcb's role looks to be an electronic alternative to either a relay or ptc start device and probably provides a soft energise for the start winding's plus some basic protection. I would tend to share the previous posters view that the rotor has probably seized

[budm]

Re: Anyone have troubleshooting knowledge of refrigerators?

"it could be open but if the bi-metal over current is tripping I suspect the rotor is locked" That is what I am thinking too.

[caphair]

Re: Anyone have troubleshooting knowledge of refrigerators?

Unless you are referring to a capacitor not shown in the pics, neither of the capacitor's on the board are motor start caps. The pcb's role looks to be an electronic alternative to either a relay or ptc start device and probably provides a soft energise for the start winding's plus some basic protection. I would tend to share the previous posters view that the rotor has probably seized

Yes I was confusing the overload (white device on left in previous pic) for the PTC/relay. So when it was "clicking" I thought that was normal as in clicking off the start winding.

Now it makes sense it was working as intended due to the motor not turning and drawing an excess of current.

If the rotor is locked, could I try hitting it with a rubber mallet to see if it'll get going or?

[terrycw69]

Re: Anyone have troubleshooting knowledge of refrigerators?

what is the make and model of your appliance

[caphair]

Re: Anyone have troubleshooting knowledge of refrigerators?

what is the make and model of your appliance

It's a GE model # GDSC0KCXARWW

[keeney123]

Re: Anyone have troubleshooting knowledge of refrigerators?

I have a friend that uses a fridge compressor to evacuate auto air conditioning, the oil is in the compressor and as long as you don't turn it upside down the oil stays in the compressor. He has been using it for years without a problem.
Check the internet for "make a fridge compressor into a vacuum pump"

if the short is only a couple windings the dc resistance will not change by much but the motor will not run.

check the run cap. it could be open but if the bi-metal over currrent is tripping I suspect the rotor is locked

Yes, I suppose he seals the output line as he would have a terrible mess. From what I have read the the bi-metal is suppose to try as this then puts the run cap in the circuit.

[keeney123]

Re: Anyone have troubleshooting knowledge of refrigerators?

I still believe the start winding need 120 Volts and it is only getting 40 volts. Here is an explain of the PTC in a refrigerator circuit.

[keeney123]

Re: Anyone have troubleshooting knowledge of refrigerators?

Here is a description of the motor you have. Which is a Resistive Start Capacitor Run. You can see this on page 1 in the first diagram. I think at the first start you should have a low resistance to the start winding and as it increases in speed the resistance should be high. Also, in the troubleshooting technique I have already supplied it say the PTC from input to output should be shorted. Also, to get the motor to turn the start winding voltage is out of phase with the Run winding voltage.

[R_J]

Re: Anyone have troubleshooting knowledge of refrigerators?

Yes, I suppose he seals the output line as he would have a terrible mess. From what I have read the the bi-metal is suppose to try as this then puts the run cap in the circuit.

Nothing gets sealed, and nothing blows oil around, thats not how it works.

[keeney123]

Re: Anyone have troubleshooting knowledge of refrigerators?

Nothing gets sealed, and nothing blows oil around, thats not how it works.

Thanks for letting me know as I thought it worked like a Car air conditioning compression. So the oil must be very heavy where it does not blow out the hi side. We made one of these in school 37 years ago. I remember them sealing off a tube. That tube must of been one of the intake or low side. I thought it had been the hi side tube but that would not make sense as the air has to go some where. So thank you again for correcting my error in thinking.

[keeney123]

Re: Anyone have troubleshooting knowledge of refrigerators?

Here is a description of the motor you have. Which is a Resistive Start Capacitor Run. You can see this on page 1 in the first diagram. I think at the first start you should have a low resistance to the start winding and as it increases in speed the resistance should be high. Also, in the troubleshooting technique I have already supplied it say the PTC from input to output should be shorted. Also, to get the motor to turn the start winding voltage is out of phase with the Run winding voltage.

Sorry I directed you to the wrong page it is page two the second diagram down.

[caphair]

Re: Anyone have troubleshooting knowledge of refrigerators?

Thanks. Still unsure how exactly the circuit works as a relay. What triggers the gate of the triac on/off?

[keeney123]

Re: Anyone have troubleshooting knowledge of refrigerators?

I service and repair fridges, typically the ones I look have two winding's a start winding and a run winding, a PTC (positive coefficient thermal) device presents a low resistance typically between 5 and 15 ohms depending on spec at start. Both start and run wingdings are energised during initial start, the start winding load causes the ptc to change its resistance with temp disconnecting the start winding.

So what voltage should be on have on the start winding when first applied?

[caphair]

Re: Anyone have troubleshooting knowledge of refrigerators?

So what voltage should be on have on the start winding when first applied?

I'm guessing full 120v what's interesting is that voltage was dropping when I tested the relay without it being connected to the compressor. Shouldn't it have been active and not dropping if tested that way?

Also how do you know for sure the compressor isn't a PSC type using a run capacitor rather than a resistive start, capacitor run type? That PDF was helpful. How'd you find it?

[keeney123]

Re: Anyone have troubleshooting knowledge of refrigerators?

Thanks. Still unsure how exactly the circuit works as a relay. What triggers the gate of the triac on/off?

So the hot side should be connected to the over-voltage protection. I actually do not think it is actually over-voltage I think it really is and over current. I believe that this will pop out and has to be manually reset.

[keeney123]

Re: Anyone have troubleshooting knowledge of refrigerators?

I'm guessing full 120v what's interesting is that voltage was dropping when I tested the relay without it being connected to the compressor. Shouldn't it have been active and not dropping if tested that way?

Also how do you know for sure the compressor isn't a PSC type using a run capacitor rather than a resistive start, capacitor run type? That PDF was helpful. How'd you find it?

I think we are looking at it wrong. The PTC is connected to the neutral line and the run winding is also connected to the neutral line. If you connect the hot side of the line to the over-voltage protection then to the hot side of the compressor. and left off the connector on the other two line. Then measure those connections on the compressor to neutral you should read 120V. I believe the PTC Shorts out the run capacitor and when open it uses the capacitor. I believe that whole board is to shift the phase of the start winding from the run winding. Once the motor starts it must use that circuit along with the run cap for efficiency of the motor by helping the run winding. You should be able to measure across the run cap with no power applied and get less than 1 ohm.