Check compressor windings with the insulation tester
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- Опубліковано 14 жов 2024
- This one covers testing the resistance to ground using both the meggohmmeter and the insulation tester. This video is part of the heating and cooling series of training videos made to accompany my websites: www.graycoolingman.com and www.grayfurnaceman.com to pass on what I have learned in many years of service and repair. If you have suggestions or comments they are welcome.
If you are a homeowner looking to repair your own appliance, understand that the voltages can be lethal, the fuels are highly flammable and high pressures are used. Know your limits.
There’s no getting around it, your videos are very informative, thank you for taking the time to explain difference between meters. Great video.
Welcome
GFM
Wow, grayfurnace man, you are on a roll with some excellent, excellent videos. This should really stimulate the brain matter. Who is doing this kind of informative video; no one but you. Those readings are a tell tale sign of something is brewing and it's not the beer! Thank you for a great video.
So glad I found your videos. I have learned so much practical knowledge thank you.
Welcome
GFM
How would you know using the insulation tester when the winding is not good anymore ? What would be the resistance value range that would tell you its not good anymore ?
Dear sir what is the exactly value of compressor with test insulation tester for example how much ohms is good
Based on the action of the regular multimeter, it almost looks like maybe a capacitor (series) was charging. And my guess would be that if your insulation tester is showing multi-megohms to ground, you have no problems, at least as far as current leakage to ground. But I don't think the tests you ran would reveal shorted windings.
watcherjohnny The insulation tester is not used for winding resistance. For that, you need factory specs and a meter that reads low resistances. This meter is generally used to determine if the windings of the compressor are approaching failure to chassis. hope this helps.
GFM
its not low enough to fail an insulation test I'd check the run current and if possible do a pump down test (plus check the start current, discharge temp etc). listen for any weird noises. compressors are incredibly expensive to replace. if in doubt always check with the manufactuer 🤔 I'm curious to see your answer video now ☺
The hermetic compressor windings live in a oil and refrigerant atmosphere. This atmosphere can become a conductor of electricity, if moisture and contamination are present in the system. The insulation tester will pick this up and give a lower reading, even if the windings are in excellent shape. A multi meter can measure in millions of ohms, but calling a multimeter a megohmmeter is very misleading.
So is it good or bad ?
Hello,
Unfortunately, clicking on the link shown at 1:14 leads to a "private video" error message.
fpliuzzi Its coming in 2 days
GFM
That was not a meg ohm meter. The insulation tester IS an insulation tester.
Electromagnetic phenomena
Its truth reading should be taken after 1 min also he didnt specify wether this was a 480v compressor. I have read that there is a conversion to housing temp and moisture as this hugely affect readings. Also hurd 1 volt per every 1kohm as a rule of thumb.
I have tried units under all these conditions, and I have never found any appreciable difference in the reading hot or cold (except if the can is very hot, the internal overload may be open). Humidity has also made no difference. Perhaps, I will test one with extreme humidity.
GFM
Replace compressor. Insulation damage present
j408garcia Check the answer video in 2 days
GFM
You say the word probably and probably are, those are not good instructional terms. To me, it probably means you do not your self. This taught me nothing of value.
I'm confused
Explain
GFM
@@grayfurnaceman Hello.I'm going to watch the video again. From what I understand any reading from either of the C,S & R terminal to the case, then the compressor is shorted out.
I got interrupted a couple of times watching it. Thanks.
What threw me off was you said you should run the unit up to operating temperature for comparing the two meters. Anytime I had to make checks on a compressor like that was because usually it was going out on the internal overload so there was no getting up to operating temperature. You meant for comparing the two. BTW, I have that megger and like it. Thanks!