How to test a fridge compressor using a multimeter

How to test single phase fridge compressors electrically. This test shows if the windings on the motor are ok. If the compressor passes this test but it can't start probably the starting relay (PTC relay) is broken or the problem is not electrical but mechanical.

So the next step I'd recommend is to focus on the starting circuitry. I'll try to make a video on that soon.

ohh and if it was helpful please subscribe

[suppressedinformation]

Thanks for the info. My compressor readings are 6.4 and 4.6 which equals 11. Third reading is 10.9 so I assume it's OK. I know the run capacitor is bad so I will see if I can install this start-up kit I bought.

[milorivera]

Super Awesome ...! just a contribution here ..mine readings  were 0.3 work/run side, 0.4 start side ..in between them ..0.7/0.8  more less ..on a whirpool fridge..from the year 05/2000  ...thx ..with your other video on the PTC relay and this one ..you just save me a trip to the store and/or a brand new FRIDGE !!!  thx mate....thumbs up !

[CSSIandAssociate]

Sir, thank you. I was pretty sure it was the PTC. However, I like to test everything if I am there. It is so nice to know that my compressor is ok.  I also have a salvaged dehumidifier. I will be testing that soon perhaps I will make a silent aircompressor out of that to blow out the computer and small jobs around the house.  Thanks again.

[kerimil]

Don't worry you're results are ok - that's precisely what you should get (2 + 8 = 10). It just happens that the unit I have has more less the same resistances of start and run windings, but they don't have to be equal at all. Given the results that you got it seems that the windings are ok - if I were you I'd focus on the starting circuitry / PTC relay as they often fail.

[kerimil]

@diego Either the windings are burned or you're not measuring it correctly. Double check it with a different multimeter to be sure

[bardinkurtis]

the higher reading prong would be the start and lower reading would be the run right?

[rickeykeeton]

Are those not high resistance readings even if the two lowest equal the highest?
I am used to readings closer to like 4, 7, and 11.
Different compressors show that much difference from the numbers I quoted? Talking about residential refrigerators myself.

[petersack]

3 pins on compressor : Top one, COMMON. bottom left. START winding. bottom right. RUN winding.

[kerimil]

Due to popular demand I made a video on testing PTC relays. Note that if the compressor cannot start you should first test the windings and if they are OK test the relay itself.

[GarciasHVAC]

Make sure you also test all terminals to ground.

[pradeepsobti]

I have the following model of Whirlpool double door refrigerator W/WRID45TW/W WHIRLPOOL REFRIGERATOR 450 LTR Top Mount White its not cooling can you suggest what must have gone wrong, does it have a defrosting timer or a PCB?

[seandurigan]

Does it matter that: run to common is 2 ohms, start to common is 8 ohms, but run to start is still 10 ohms? I thought the first two measurements were supposed to be about equal.

[alunroberts]

Thanks for this going to show to guy am fixing one for well I did fix it someone else changed the compressor wired it the power then blows now it is open on one side. I forget which side but that doesn't matter.

[kerimil]

yeah, it seems perfectly fine. Even barely noticeable corrosion on the surface of the prongs or tips of multimeter probes can result in much greater deviation - so 0.1ohm is pretty damn accurate

[DreDiego]

Im getting no reading on my fridge compressor, does it mean it's dead/done/garabage?

[coolmonkey]

what does it mean if the windings are bad

[juanchemaly]

Hello can tel me i don t have an tester but i got water on te floor and the compressor makes an bubbeling

[aflarry]

I tested and bought a start relay works great for 5 to 7 days then compressor fails to start but tries.  Turn it off for 2 to 3 hrs then runs fine for another 5 to 7 days.  All cleaned no obstructions.  
Does an 8 yr old compressor act like this when defective?
Any idea what the problems is?
Thanks

[ns]

my readings are all 6.5 Ohms;  tween terminals and compressor body there is no continuity; so no shorts in windings but between all terminals the readings are all 6.5 ohms; are the windings failing?
thanks in advance,            Lou

[robertjohnsonsr]

So how about explaining why in the frickin hell my compressor checks out yet still don't work! After a bunch of searching i find out AFTER doing what you did ( AND SEVERAL OTHERS THAT HAVE NO IDEA WHAT THE FUCK THEY ARE DOING) you need to check for shorts by touching A probe to run (or the other pins) and a probe to the compressor or copper tube! this where my short was! :(