pump is humming, but shaft turns

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kwired said:
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.
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Yes, It's called knowing when to hld 'em and knowing when to fold ,'em.
 
GoldDigger said:
A turn to turn short will cause noise and high current without showing up in a DC resistance measurement.
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I usually find open winding, or shorted windings by measuring resistance between phases on motor.

I guess on 220 I couldn't compare resistance,

so I would not know what a shorted winding would look like,

easier on a three phase.
 
big john said:
What does your current and shaft speed look like? Is it possible you have a problem in your starting circuit?
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no start circuit, well not a fancy one anyway.

just a intermatic 30 amp timer, that pulls in twice day, and starts the pump full speed.

no soft start of VFD, (I wish)
 
templdl said:
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.
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wow,

got any diagrams?

or prints?

on similiar motors?

I see a switch on the motor.

I pulled the capacitor off, tested it, got good uf rating,

pulled the terminations off, and crimped them slightly tighter,

reinstalled, and now instead of humming it just trips the 20 amp 220 main on the house.

But that was all I did.

I marked the wires, and made sure they didn't pinch nothing.

not quite sure.

come to mention it, I had the same bad luck on my accord starter tonight.

I pulled the battery cables off, load tested battery, reinstalled.

and now instead of turning over sluggish like, all I hear is a whining.

the closest sound I could explain it as, is it's like the cooling fan ceased.

then I shorted the starter to the chassis and blew my main battery fuse.

better luck tomorrow.

I was trying to pry the boot back on, and it cut through and shorted my flat head to the engine block.

(lets just say I am better with electical than mechanics!)

but I am trying at least.

little by little.
 
ActionDave said:
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.
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yeah caps like to overheat, and leak out greyish, blackish, greyish pasty stuff.

but for some reason this cap is testing okay with my DMM, on the capacitor function.

Do you guys use the capacitor function or the ohm meter setting to test CAPS?

I know you can use an analog.

but I don't have one of those.

I bought this for 50 bucks 20,000 count True RMS- with data logging, and 40mohm I believe resistance.

It's powerful enough to see shorts in wire and flex. 90 perent of time I can tell a shorted motor or wire, without going to shop for our meggar.

Model # UT-61E UNIT

I serveimage.jpg

but I am used to ohming out capacitors, and not used to having a cap function.

I guess they work ok.
 
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ActionDave said:
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.


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.
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I am sure the bearings are not great,

but I can turn it with channel locks on the shaft.

I hear stuff grinding and crunching.

(one guy on you tube pool service, said that these pumps get corroded inside and you can turn the shaft 10-20 times and free it up).

but he was a jack of all trades apparently,

more likely he is just turning the grease in the shaft or fan/rear bearing and creating less resistance.

I have seen that too.

I have been working on my starter today on my car, tomorrow the pump again.

I have two now, I figure I can try a slightly larger capacitor temporarily.

to see if it act like a hard start you see on those compressors on AC units.

basically an oversized cap.

I broke off the case screws, so I will have to extract, and retap.

already got the new ones.

(but that is my old pump, that was ceasing up around the seal. It had a rubber liner, and it seemed the impeller would rub on it,

I didn't like the design, so I was focusing on this pump.

instead.

trying to get it electrically sound again.
 
godsquadgeek said:
yeah caps like to overheat, and leak out greyish, blackish, greyish pasty stuff.

but for some reason this cap is testing okay with my DMM, on the capacitor function.

Do you guys use the capacitor function or the ohm meter setting to test CAPS?

I know you can use an analog.

but I don't have one of those.

I bought this for 50 bucks 20,000 count True RMS- with data logging, and 40mohm I believe resistance.

It's powerful enough to see shorts in wire and flex. 90 perent of time I can tell a shorted motor or wire, without going to shop for our meggar.

Model # UT-61E UNIT

I View attachment 13369

but I am used to ohming out capacitors, and not used to having a cap function.

I guess they work ok.
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I always use a Megger for testing LV capacitors. Full voltage in both forward and reverse directions.

It takes a while to charge the capacitor so be patient and have spare batteries at the ready.
 
Tony S said:
I always use a Megger for testing LV capacitors. Full voltage in both forward and reverse directions.

It takes a while to charge the capacitor so be patient and have spare batteries at the ready.
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Never in my wildest would I have thought to use a megger at its highest setting to test LV caps. Especially when they are rated in voltage and the surest way to destroy one is to use it in an application that is over voltage. Current would be low though.

Usually a continuity tester will give a quick pass/fail.
 
godsquadgeek said:
no start circuit, well not a fancy one anyway.

just a intermatic 30 amp timer, that pulls in twice day, and starts the pump full speed.

no soft start of VFD, (I wish)
Click to expand...

By start circuit we are talking about the aux winding, capacitor, and the centrifugally operated switch that cuts out the starting capacitor, your intermatic timer is the "controller".

Single phase induction motors are really "two phase" motors. There is always at least two windings and a method to create some phase shift between them. If they don't have a phase shift you never have any rotational effect on the rotor, if one of those windings or the components in their circuit fails - you lose the phase shift and have no torque to cause rotor to turn.

godsquadgeek said:
I am sure the bearings are not great,

but I can turn it with channel locks on the shaft.

I hear stuff grinding and crunching.
Click to expand...
As has been said you should be able to turn it pretty easily with just your fingers. Now you need to determine if the resistance is something in the motor or in the (likely attached) pump. If in the pump maybe just something that can be fairly easily cleared out, otherwise is most likely most cost effective to just replace the pump and/or motor.
 
ptonsparky said:
Still want to make that bet after:

"...I am sure the bearings are not great,

but I can turn it with channel locks on the shaft.

I hear stuff grinding and crunching..."
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When the bearings get worn out, it doesn't mean they will lock up the shaft. You will get grinding and crunching, and humming when it is running.
If it takes channel locks to turn, then they are bad. Because you should be able to spin even a big 3 phase motor shaft with two fingers.
 
Chanel locks to turn it ,grinding noise ,Oh well it's only a dollar.
 
grinding noise still leaves us with a few possibilities.

Bearings has been mentioned, but if pump is still coupled could be broken impeller in the pump housing, broken cooling fan inside motor housing, other foreign material has entered the motor housing, bearing wear is severe enough that rotor is actually rubbing the stator...

We are still left with the fact that on a small pump/motor like the OP has not too many of those items are worth fixing as a replacement pump/motor is likely going to cost less anyway.
 
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