pump is humming, but shaft turns

[godsquadgeek]

windings are not shorted, windings are not open.

bearings turn.

so I am not quite sure what else it could be.



I think it may be corrosion on the windings from being outside.

they are 300 bucks and I would like another season or more out of it.

any experience with this type of pump?

I also have another one, that is ceasing up, I may try to change seals on it instead.

probably take it apart and find the shaft seal size and take it in.

 

[GoldDigger]

A turn to turn short will cause noise and high current without showing up in a DC resistance measurement.

 

[big john]

What does your current and shaft speed look like? Is it possible you have a problem in your starting circuit?

 

[templdl]

windings are not shorted, windings are not open.

bearings turn.

so I am not quite sure what else it could be.

View attachment 13349

I think it may be corrosion on the windings from being outside.

they are 300 bucks and I would like another season or more out of it.

any experience with this type of pump?

I also have another one, that is ceasing up, I may try to change seals on it instead.

probably take it apart and find the shaft seal size and take it in.

Looks like a 120v 1ph motor. If so shaft turns, motor hums when energized, motor does not start spinning is a starting issue. These motors typically have a run winding and as start winding. Both the start asnd run winding should be energized at the same time when the motor is first energized. The start winding provided a phase shift in a start winding which causes the motor stator to start spinning. As the stator accelerates a centrifugal switch will disconnect the start winding and the spinning motor will continue to spin.
Thus, check to see in the centrifugal switch in closed with the motor sdtspped and check to see if the contacts and not defective. In it looks as if that's not the issue it may be a failed start winding that in no longer functioning.

 

[iceworm]

slow poster - templdl got it.

if not the centrifigual switch, check the capacitor

ice

 

[milldrone]

so I am not quite sure what else it could be.

View attachment 13349

The first things I check when troubleshooting single phase motors are the centrifugal switch and or the cap if any. Have you checked the Capacitor? Have you checked the centrifugal switch ( the color looks a little off in the photo). Is it welded? Lastly I do not like the proximity of the red wire to the centrifugal spring.

 

[templdl]

slow poster - templdl got it.

if not the centrifigual switch, check the capacitor

ice

Damn!! I didn't think there was anybody slower at typing than I am.
But with the minimum of information that has been provided it is my guess that this may be a sump pump moto. Because centrifugal pump starting torque requirements are low they often don't require a starting cap.

 

[Tony S]

Looking at the picture like others I would go for a dirty contact on the centrifugal switch.

If this is any help

Please don’t do what a friend did testing the capacitor. He put his finger across the terminals with it charged, I didn’t know you could get that many ####’s in one sentence.

 

[ActionDave]

Damn!! I didn't think there was anybody slower at typing than I am.
But with the minimum of information that has been provided it is my guess that this may be a sump pump moto. Because centrifugal pump starting torque requirements are low they often don't require a starting cap.

It's not a sump pump. It's an AO Smith irrigation or pool/spa pump.

I agree with others about the switch or the cap. The switch is nice because it's right there and easy to check. If you made me choose I'd go with the cap.

 

[ActionDave]

windings are not shorted, windings are not open.

bearings turn.

so I am not quite sure what else it could be.


I think it may be corrosion on the windings from being outside.

they are 300 bucks and I would like another season or more out of it.

any experience with this type of pump?

What is it, irrigation pump?

Windings don't go bad from being outside. Windings go bad because of excessive heat. The motor not starting or the pump not working properly or the pump trying to move too much water can all cause overheating.

Just because the shaft turns does not mean there is no problem with the bearings, starting switch, starting capacitor, or pump. Sometimes it is a problem with the wiring to the pump.

Switch on those motors is easy to check, flick it with your finger and run a nail file between the contacts.

Starting caps can and do go bad, but often they are the canary in the mine because they are the weakest link when something is wrong with the motor not starting. Does the motor have a running cap?

Bearings should be whining if they are going bad.

I also have another one, that is ceasing up, I may try to change seals on it instead.

probably take it apart and find the shaft seal size and take it in.

Changing the seal won't help. Changing bearings likely will. You have to get the impeller off to do that so you will need a new seal anyway.

 

[templdl]

It's not a sump pump. It's an AO Smith irrigation or pool/spa pump.

I agree with others about the switch or the cap. The switch is nice because it's right there and easy to check. If you made me choose I'd go with the cap.

Good point. Caps on single phase motors are ready to see as they are those hump type appendages on the side of the motor. A motor with capacitor start will have only one where the higher HP will have (2) for capacitor start and capacitor run.
Since there in no ovrsll picture on the motor and no nameplate picture it's see sometimes diffct to provide a diffintve answer.

 

[kwired]

Good point. Caps on single phase motors are ready to see as they are those hump type appendages on the side of the motor. A motor with capacitor start will have only one where the higher HP will have (2) for capacitor start and capacitor run.
Since there in no ovrsll picture on the motor and no nameplate picture it's see sometimes diffct to provide a diffintve answer.

Most motors I have seen with the capacitor in the motor end housing like pictured in the OP that is the only capacitor. Most of those type are found on swimming pool/hot tub pump motors or some jet pump type well or booster pumps.

Going back to OP, I don't know how you checked continuity through the motor but you can't just check continuity through the input leads, you need to verify continuity through both main and aux windings - it will not start if you don't have proper circuit through both windings. If it is a dual voltage motor operating at the lower voltage, you can have open circuit in one half of main winding but still read continuity through other half as they are connected in parallel for low voltage operation.

 

[templdl]

Most motors I have seen with the capacitor in the motor end housing like pictured in the OP that is the only capacitor. Most of those type are found on swimming pool/hot tub pump motors or some jet pump type well or booster pumps.

Going back to OP, I don't know how you checked continuity through the motor but you can't just check continuity through the input leads, you need to verify continuity through both main and aux windings - it will not start if you don't have proper circuit through both windings. If it is a dual voltage motor operating at the lower voltage, you can have open circuit in one half of main winding but still read continuity through other half as they are connected in parallel for low voltage operation.

Oh, is to under that insulator on the left side? I thought it would be too big to put there but I guess not.

 

[Little Bill]

Oh, is to under that insulator on the left side? I thought it would be too big to put there but I guess not.

Yes it is under the protector/insulator on the left side. It is similar in shape to a "D" battery and has the yellow & red wires coming from it.

I agree this is probably a pool or spa motor. It is dual voltage. The input terminals have a slide to adjust for 230V or 115V. You connect your inputs after you move the slide to the appropriate voltage setting. It has a start capacitor, the one described above, and a centrifugal switch.
My guess is also on the cap being bad.

 

[templdl]

Yes it is under the protector/insulator on the left side. It is similar in shape to a "D" battery and has the yellow & red wires coming from it.

I agree this is probably a pool or spa motor. It is dual voltage. The input terminals have a slide to adjust for 230V or 115V. You connect your inputs after you move the slide to the appropriate voltage setting. It has a start capacitor, the one described above, and a centrifugal switch.
My guess is also on the cap being bad.

I'm not sure if the cap in replaceable but if so it can't be an expensive of a part. If it was replaceable and that was't it then it wasn't that of an expensive part and the motor is most likely junk.

 

[degupita]

The bearings will turn, even if they are at that stage of needing to be replaced. They will hum.

I got into electrical initially as a pool and spa tech, and have replaced many bearings, seals, and whole motors and pumps.

If it is just a residential pool or spa pump, just replace the motor. Or try to get the bearings.
If it is commercial, take it apart and replace the bearings and seal.

 

[kwired]

I'm not sure if the cap in replaceable but if so it can't be an expensive of a part. If it was replaceable and that was't it then it wasn't that of an expensive part and the motor is most likely junk.

Can't tell the MFD/voltage of that capacitor, but most small capacitors similar to that one are only $15 max at Grainger, maybe can do better at a motor shop or even HVAC supplier - but time spent going there may not be worth it compared to just ordering from Grainger. Depends on your location and proximity to such places as well.

 

[degupita]

You can replace the capacitor, but the motor will still hum, because it isn't the start up and run Cap that makes that sound. It is the bearings on the shaft.

 

[Galt]

bet a dollar new cap. makes it go.

 

[degupita]

I'll bet $3