# My first insulation resistance test



## joebanana (Dec 21, 2010)

Considering anything below a 2 on a PI test is no good, and anything below 300k ohms for a 600v. motor is no good. Maybe drying out the motor will improve things.


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## ppsh (Jan 2, 2014)




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## gpop (May 14, 2018)

Worst thing about a submersible pump is you need to pull them to see if the pump really is the problem. This may be the motor or the cable/underwater splice.


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## Cow (Jan 16, 2008)

You have a current imbalance of 21 amps, more than 10%. I would have checked voltage ab, ac, bc. Small voltage imbalances can make big current imbalances. I would of also rolled the phases over if necessary to see if the higher current followed the wire. Or the phase.


What voltage did you meg at?


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## MechanicalDVR (Dec 29, 2007)

gpop said:


> Worst thing about a submersible pump is you need to pull them to see if the pump really is the problem. This may be the motor or the cable/underwater splice.


That is when you explain to the person in charge you can pull it and find it's not the motor and approach the subject of having a new motor onsite and then pulling and making a repair.

If it isn't the motor they can keep the new motor as a spare, install the new motor keeping the old one as a spare, or send back the new motor.

Options!


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## tmessner (Apr 1, 2013)

just remember that submersible motors are a lot of power packed into a very small space.


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## gpop (May 14, 2018)

I had a little 2hp today that tripped its heaters.

Reset then test ran and its read A=1.5 B=5 C=3 first phase i checked was c so it looked good then i amp clamped all the legs together and seen a problem so i clamped each leg. 

Tested voltage which was good then opened the mjb to check the connections which were good. 
it passes a megger test to ground so its in the coils which is no surprise.

The op's motor is megging bad and it has one leg pulling more amps than the others. If the voltages are close then you have to wonder where 21 amps is missing. Normally you would expect it to show on another leg so i suspect that its on the ground cable. 

Still doesn't answer the question of if the motor is bad but it shows that this should be fixed asap. I wouldn't be surprised to see a large hole in the pipe that goes down to the pump as electrolysis is probably happily eating away at the pipe. At a guess i would suspect a failed splice as the resistance of water would allow this to happen. 

Either way you look at it i would go with what Mechanicaldvr said and have cable, motor and splice kit ready to go.


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## triden (Jun 13, 2012)

Cow said:


> You have a current imbalance of 21 amps, more than 10%. I would have checked voltage ab, ac, bc. Small voltage imbalances can make big current imbalances. I would of also rolled the phases over if necessary to see if the higher current followed the wire. Or the phase.
> 
> 
> What voltage did you meg at?


Voltage imbalance was less than a volt


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