Diagnosing a Grounded Compressor 3D
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- เผยแพร่เมื่อ 16 ต.ค. 2023
- This 3D video will show the process of diagnosing a grounded compressor in a split residential HVAC system using isolation diagnosis. We may also call these compressors “shorted to ground.”
When you find a tripped breaker, avoid resetting it; it may be tempting to reset the breaker and see what happens, but the breaker is tripped for a reason; closing the circuit again may cause the overcurrent condition to create a major arc or spark. Shorts at the compressor may also cause carbon and acid to enter the refrigerant and contaminate the system.
Our diagnosis should start off with a solid visual inspection of high-voltage wires, terminals, contactor, capacitor, crankcase heater, breaker, and disconnect. At this time, we must take extra care to note wire rubouts or abrasions, signs of arcing, and loose connections.
Then, we’ll inspect the compressor leads and terminals, wearing appropriate PPE. Before removing the compressor wiring, take a picture of the terminals so that you can remember how the compressor was wired when it’s time to put it all back together.
With the wires pulled off, you can measure the resistance to ground at each terminal with a megohmmeter, using the suction or discharge line as your ground. The quality of the reading will depend on the quality of the meter you use. Low resistance values indicate a short, though a short may also be present even if your resistance values are within the acceptable range.
Abrasions and black stains on the windings are also signs of a short. However, stains may also contain enough carbon to insulate the shorted area, causing a regular resistance reading. When high voltage is applied, the low resistance will show up when reading in the megohm scale.
If you have evidence that the compressor is shorted to ground, you can isolate the compressor by taping or plugging the terminals so that they don’t touch anything. Then, you can reassemble the unit and run it without the compressor. If the breaker doesn’t trip, and everything runs correctly, you can be sure that the compressor is grounded. If the breaker still trips, then you can confirm that a grounded compressor is not the issue.
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Another great animation! Thanks🤝
These animations aren't easy to make. Great work!
Thanks a lot!
Such an awesome training video. Definitely make more of these animations!
The animation and narration were flawless, thanks for sharing!
Always a good refresher with good explanation 👍🏼
I’m really enjoying the animation so much better to understand the process we need more thank you
Wow that made look very easy and now I’ll know how to check for a grounded compressor. I used to have to call my professor and this had to share something with him, now I’m sure I can go ahead myself and do this. Gonna have to save this video in my favorites, this will be number one, keep up the great videos for us beginners. As only hands on apart from schooling will we learn.❤
Extraordinaire! As always. Thank you so very much for the effort made.
These animations are great. Thank you.
The work put on this video is 10+
Really great learning material. Thank you 🎉
YOU DA BEST BRYAN! Much love from New Orleans!!❤️
Thanks Bryan Ore you are a great teacher ma man!
Great video training thanks HVAC School
Amazing animation, good stuff, well taught
Always great content! Thanks
Excellent presentation
Very informative video, great animation .👍👍👍👍
By far the animated education I've seen I literally want to get into HVAC because of this, just don't know if I can afford the schooling
Appreciate your videos
Beautiful. More please.
top notch as usual
thank you for this video !
Glad it was helpful!
@@HVACS even after i graduated, I still watch your videos so it becomes engraved in my mind !
I appreciate the videos
excelent v 3d video,please continuos with more videos
Good illustration. Wish I knew how to to that.
Damn these animations are some Hollywood disney level!!😮
great,,,,more videos,,
Thanks!
I usually add R22 until the head pressure hits 700 and the compressor gets super hot. I also throw water straight on the transformer and take out the fuses and use 00 copper wire to straight wire it
LMAOOOOOOO
i usually start by unwiring the high voltage from the contactor of condensor. it makes it clear to me which direction to go next. my next step will be the compressor wire harness or the disconnect (depending if breaker tripped) then ill unwire the crank case heater and fan individually at a time. its usually one of them if its not the compressor.
Perfectly
Really helpful! To you have a metric option for your online calculators?
Not yet!
Sponsored by… Square D… To be fair, Schneider has great products, including some very interesting cooling equipment…
Had a compressor tripping over the weekend, we can’t leave it isolated to run for that long is there another way?
Jandy was here.
👍
✅✅✅
So if we get a high resistance it’s bad? And if we get a low resistance there is no short?
I'm assuming you're referring to the 22 vs the 5? The 22 was k(il)Ohms and the 5 was M(eg)Ohms. 1 kOhm is 1000 ohms, whereas 1 MOhm is 1 million ohms. When testing a motor terminal to ground, you want the resistance to be effectively infinite (OL for open line for standard meters, or something in the megohm range for a megger).
@@EpyonRules thank you. Another question, so when checking to ground you don’t want any resistance just ol. Thanks for your help.
@@Sc19869you don’t want any resistance so when you’re measuring in ohms you should O.L or 0.000 reading no resistance
@@JesusLopez-tz8yv That's not true. When measuring to ground (with a regular/non-megger meter) you want OL. 0 ohms is bad in this instance because it means that there is a direct path from the winding to ground. OL and 0 ohms are two VERY different things.
Edit for clarification: OL means there is no path. 0 ohms means that there is a path with no resistance.
@@EpyonRules ol means you have an open circuit correct. And 0 ohms meant you have high current, so there is a short.
Wouldn’t you want to check the Fan Motor for a short also?
Hence the title of the video "Diagnosing a Grounded Compressor." The focus is the compressor because 90-95% of the time, it'll be the compressor that is tripping the breaker.
If you follow the instruction and steps on this video, after isolating the compressor and the breaker STILL trips, 3-8% of the remaining possibilities will be a wiring issue. If you follow the instructions of the video, you'll have seen it BEFORE having to isolate the compressor, BUT can't always catch it.
It's very rare that the condenser fan motor will be internally shorted. Almost always the condenser fan motor will be seized and obvious when resetting the breaker and testing the unit. This can eventually cause the compressor to run extra amperage for a long period of time and the second way a breaker will trip.
My first test for a compressor is to move the blades attached to the fan motor and if it's stuck or if it DOESN'T move with more than a tap OR if the blades stop way to soon and sudden, the motor has seized or will seize the moment it gets power.
Lastly, I've seen this in the field, is a fan motor that HAD been replaced but the drain plugs were not moved from one end of the motor to the other, depending on the way the motor sits. This causes water to COLLECT in the motor casing and will POSSIBLY (unusually motor is newish) cause a short. But more than likely, will rust the stator and metal to the point where friction and heat will cause the motor not to turn.
If you depress suction Schroeder valve and it smells like acid, you have a failed motor.
Fox Family HVAC guy
🤍🤍🤍