Pool pump immediately trips breaker - bad breaker, bad capacitor, bad pump?

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S

squirk

0
Sep 9, 2016
89
Southeast Louisiana
Pentair filter pump (five years old) was running just fine this morning. Then this afternoon, I noticed it stopped (timer is supposed to have it running until 6 p.m.).

The breaker for the pump had tripped. I turned off the pump via the timer switch, flipped the breaker off and back on, and then turned the pump back on (again, via the timer switch). The pump revved up as it normally does, for literally one second, and then the breaker tripped again. I repeated this several times, with the same result.

It hasn't rained, so the breaker box did not get wet. The other breakers inside the box (lights, spa blower, septic pump, GFI outlet) all work just fine, so the problem seems isolated to the pump breaker and/or the pump itself.

One thing I did notice - when I flip the pump breaker off and then back on (but before I try to switch the pump itself back on), I hear a few soft clicks/buzzing from behind the breaker switch.

Of course, stuff like this always seems to happen on a weekend, so until I can get someone to look at this on Monday or Tuesday, I am left with a nagging fear that my pump is shot.

I am hoping that these symptoms - particularly the clicking/buzzing from the breaker switch - are more indicative of just a bad breaker, which would be a relatively quick and cheap repair.

No guarantees, of course, but if anyone here knowledgeable about such things could set my mind at ease, I would be very grateful.

Please and thank you!
 
If it's a motor with a capacitor, I'll assume it's 120 volts, not 240. So if you're seeing it try to start, make a big racket, and trip the overcurrent, I'm guessing it's the capacitor. If you had shorted windings, you'd trip the breaker right away most likely.

What the capacitor does is basically boost the current to get the motor spinning, then disconnects itself from the circuit via a centripetal switch when the motor gets up to speed. Multiphase motors (240V or 480V) already have that rotating magnetic field, so they don't need a capacitor to simulate it.

Your pump is probably fine. I'd take the whole thing to an electric motor shop and have them test the capacitor and the motor windings just to be sure.


I just saw you mentioned a buzzing or clicking in the panel? It's possible the breaker may be loose on the buss that feeds it. Turn off the power, take the cover off and check it out if you feel comfortable with that. If not, don't touch it. That wouldn't be the cause of the motor tripping the breaker, but it may lead to problems down the road.
 
Jhsparky82 said:
If it's a motor with a capacitor, I'll assume it's 120 volts, not 240. So if you're seeing it try to start, make a big racket, and trip the overcurrent, I'm guessing it's the capacitor. If you had shorted windings, you'd trip the breaker right away most likely.

What the capacitor does is basically boost the current to get the motor spinning, then disconnects itself from the circuit via a centripetal switch when the motor gets up to speed. Multiphase motors (240V or 480V) already have that rotating magnetic field, so they don't need a capacitor to simulate it.

Your pump is probably fine. I'd take the whole thing to an electric motor shop and have them test the capacitor and the motor windings just to be sure.
Click to expand...

Thank you!

The pump doesn't make a "racket", really. It makes the same exact sound as when it starts up normally. The breaker just trips literally one second later.

A blown capacitor would be fine. Like the breaker, a cheap and quick fix. I just don't want to have to mess with replacing the pump.

Thanks again.
 
Jhsparky82 said:
I just saw you mentioned a buzzing or clicking in the panel? It's possible the breaker may be loose on the buss that feeds it. Turn off the power, take the cover off and check it out if you feel comfortable with that. If not, don't touch it. That wouldn't be the cause of the motor tripping the breaker, but it may lead to problems down the road.
Click to expand...

Thanks. I am not skilled enough to mess with that.

When I flip the other breakers (lights, air blowers) off and then back on, I hear nothing behind the panel. When I flip the pump breaker off and then on, I hear that faint buzzing/clicking. So there is something different there.

I forgot to mention that the the first time the breaker tripped, when I flipped it back on, the pump actually ran for a few minutes, and then it tripped again. After that, it would consistently trip within a second after starting the pump.

I’m just trying to convince myself that all this is going to take is 30 minutes and a $15 breaker or capacitor.
 
Yeah, that's a capacitor. Shorted windings would trip immediately. The motor is trying to start, but you're overloading it without a capacitor and it's either tripping the overcurrent or it's got internal thermal overloads (not likely tho).

As for the breaker, it's probably just loose. The sound you hear is arcing when it closes the circuit. Motors have a big inrush, the power it takes to get the motor to spin from a dead stop. Sometimes 6 times the running current. So that's a lot of current and if there's resistance, like a poor connection, you'll hear sparking and crackling.
 
Jhsparky82 said:
Yeah, that's a capacitor. Shorted windings would trip immediately. The motor is trying to start, but you're overloading it without a capacitor and it's either tripping the overcurrent or it's got internal thermal overloads (not likely tho).

As for the breaker, it's probably just loose. The sound you hear is arcing when it closes the circuit. Motors have a big inrush, the power it takes to get the motor to spin from a dead stop. Sometimes 6 times the running current. So that's a lot of current and if there's resistance, like a poor connection, you'll hear sparking and crackling.
Click to expand...

Thanks again. I appreciate all your input.

I guess I am now wondering why the breaker tripped in the first place. If the capacitor is only needed for start-up, and then disconnects itself, would a bad capacitor trip a breaker after the pump had been running fine for six hours?
 
Jhsparky82 said:
If it's a motor with a capacitor, I'll assume it's 120 volts, not 240. So if you're seeing it try to start, make a big racket, and trip the overcurrent, I'm guessing it's the capacitor. If you had shorted windings, you'd trip the breaker right away most likely.

What the capacitor does is basically boost the current to get the motor spinning, then disconnects itself from the circuit via a centripetal switch when the motor gets up to speed. Multiphase motors (240V or 480V) already have that rotating magnetic field, so they don't need a capacitor to simulate it.

Your pump is probably fine. I'd take the whole thing to an electric motor shop and have them test the capacitor and the motor windings just to be sure.


I just saw you mentioned a buzzing or clicking in the panel? It's possible the breaker may be loose on the buss that feeds it. Turn off the power, take the cover off and check it out if you feel comfortable with that. If not, don't touch it. That wouldn't be the cause of the motor tripping the breaker, but it may lead to problems down the road.
Click to expand...
All in ground single speed pumps use a capacitor whether they are 120 or 240.

The capacitor is either a start capacitor or a run capacitor.

The start capacitor is taken out by a centrifugal switch.

A run capacitor stays in the circuit.

120 and 240 residential power is usually single phase and not three phase.
 
If it is truly a bad capacitor causing the failure, and the motor is running for a longer period and tripping the breaker, it could be a PSC motor or Permanent Split Capacitor motor. This capacitor remains in the circuit even after start up. Due to it's design, if the capacitor fails, it would operate at a higher current without the second winding in the circuit. This typically results in an IOL trip, but not always.

Another issue can be a capacitor start induction run motor not dropping out the start capacitor properly. Or the start switch failing.

Also, the windings of a motor have an insulation coating to prevent arcing. When a motor ages and over heats the insulation resistance is reduced and it can reduce the ability for the coating to do it's job. This sometimes results in random breaker tripping. They make insulation resistance meters called meggers or high potential testers. Basically it's an ohm meter with an adjustable voltage, much higher than 9v from a standard ohm meter. Usually 250v-1000v. These meters test leakage to ground.
 

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JamesW said:
The bump on top is the capacitor. Check that.
Click to expand...

I don't know what I'd be looking for. I have a poor track record messing with electrical components. I'm happy to have someone else come out and swap the capacitor out. I had a bad one about 18 months ago, and I remember it was a cheap call.

JamesW said:
The number you gave is for the motor.

The pump model and manufacturing date should be on a label on the pump.
Click to expand...

Three different labels. None of them appear to give me a model number, but it's a WhisperFlo - Manufactured 6/8/2015.
 
Replace the capacitor. You can get them online cheap.

Get the model number from the capacitor and Google for a replacement or go to a local electric motor repair shop.

Your pump model number is WF-6.

It's a single speed, full rated pump with a total of 2.2 hp.
 
Well, I tried it again this morning, after letting it sit overnight. The pump actually started up - not humming, but actual operation - for perhaps 10 seconds, and then tripped the breaker. Back to where I was yesterday, with the breaker tripping almost instantly.

I'm puzzled as to why I got the 10 seconds though......
 
10 seconds probably means that the amperage exceeds the breaker's rated amperage by at least 135%.

Breakers only trip immediately if there is a direct short. If the amperage exceeds the breaker's rated amperage, the trip time is determined by how much the amperage exceeds the breaker's rated amperage.

The time is non-linear. At 5 to 10% overload, the breaker might take hours to trip or might not trip at all

A breaker only has to trip (by code) at 135% overload and at 135%, they can take up to an hour to trip.

What is the breaker rating and what amperage is listed on the motor?

https://goodsonengineering.com/wp-content/uploads/2017/08/CircuitBreakerMyths_web.pdf

Try a new capacitor.
 
Clearly, I don’t know much. But I am going to take a leap and say my capacitor is indeed shot.

3B178382-01D9-4B34-9E4B-72C0152837AD.jpg



JamesW said:
10 seconds probably means that the amperage exceeds the breaker's rated amperage by at least 135%.

Breakers only trip immediately if there is a direct short. If the amperage exceeds the breaker's rated amperage, the trip time is determined by how much the amperage exceeds the breaker's rated amperage.

The time is non-linear. At 5 to 10% overload, the breaker might take hours to trip or might not trip at all

A breaker only has to trip (by code) at 135% overload and at 135%, they can take up to an hour to trip.

What is the breaker rating and what amperage is listed on the motor?

https://goodsonengineering.com/wp-content/uploads/2017/08/CircuitBreakerMyths_web.pdf

Try a new capacitor.
Click to expand...
 

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