Single phase ac pump getting hot

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Old 07-31-18, 03:02 PM
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Single phase ac pump getting hot

Hi guys,
so I have this pump that was upgraded to an electronic start circuit using a SINPAC motor starter, which disconnects the start winding / capacitor at 70% RPM.
After modification, it runs hot -which I have not noticed before.
There is a diagram on the cover of the connection box which puzzles me somewhat. It looks like starter and run windings are supposed to be connected to the line through caps. I don't see anything that indicates the start winding is disconnected during runtime.
The plate says CS, which in my opinion means capacitor start, but not capacitor run.
Currently, it is setup in a way that disconnects the start winding at runtime.

I have attached a diagram showing the hookup in hopes that anyone can explain why they have capacitors on all windings.
 
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Old 07-31-18, 03:15 PM
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Another try with the link to image

 
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Old 07-31-18, 04:24 PM
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That diagram appears to be for changing the rotation of the motor.
 
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Old 07-31-18, 11:41 PM
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What did it use for starting before the "upgrade" ?
We'll need more motor info.
 
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Old 08-01-18, 12:12 AM
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Yes, the diagram gives instructions on how to change the rotational diection, but I am still confused about all the cpacitors on there. Maybe they were not even meant to be capacitors, but just tried to illustrate some sort of a terminal block?

Before the modification, I believe a centrifugal switch was used to disconnect the starter winding.
However, I don't know what or how many capacitors were in there before. Now there are just 2 400MFD caps in series plus the solid state controller.
I was thinking, what would happen if one accidentally used the starter winding as the run winding. Would the motor still run? Provided the run winding is disconnected of course.
I suspect the power output would be low and the temperature rise would probably be higher, but I am not sure if it would actually run without burning up the starter coil.

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Old 08-01-18, 02:49 PM
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Hmm, I suppose it's possible the start and run windings could have been swapped. You should be able to test on the ohms setting of a multimeter. With all other motor windings disconnected, the resistance of the start winding should be higher than the run winding. Sometimes the start leads will be of a smaller wire diameter than the run leads.

How many leads do you have coming out of the motor? Are they identified in any way? There should be a minimum of three (start, run, common); but there might be more.
 
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Old 08-01-18, 02:56 PM
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You had an electronic starter installed to replace the centrifugal switch...... who did that work ?
If you paid to have it done..... it should be repaired correctly.
 
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Old 08-01-18, 06:57 PM
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I think those parallel "plates" are contacts, not caps. Unfortunately, they are the same symbols in many US based prints. I've never seen 3 caps in a fractional HP AC motor.
 
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Old 08-10-18, 06:51 PM
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Hi guys,

I opened the motor up and found some cotton tissue-like insect nests blocking the airflow. Cleaned it out and the motor runs cooler now.

@PJmax:
I had a company which specializes in electrical motors do the work, and yes, normally one would expect that they know what they are doing. But then again, it is humans who do the work. And I guess we all know what that means

@Telecom guy:

Thanks for the explanation of the symbol. I looked at a few diagrams of motors and came to the same conclusion.

Will keep an eye on the temperature, but for now it seems ok to operate.
 
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