Need Electrician to Explain Freak Happenstance

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I recently lost a pool pump because the motor blew the starter capacitor.

I'm told this can happen due to a power surge.

Coincidently I saw this:



A deceased hummingbird still attached (literally clutching) our house ground.



Related?
I replaced the motor BTW.

What could have caused this?
 

Fingers

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Hmmm. The starter capacitor does a power factor correction to compensate for inductive reactance at low speeds. I would expect that if something blew, it would be the main coil owing to the lower voltage caused by the high impendance short of the bird. The having been said, I wouldn't expect that the bird was the source of your problem. It was probably a coincidence. Your motor blew up and you went looking for a cause and found the bird. It could have been there for some time.

If it was your start capacitor, the probable culprit is the centrifugal switch. When the motor gets up to speed, it's supposed to throw and take the cap out of the circuit.
 
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olllllo
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I wasn't blaming the bird. I was wondering about the cause for sure, and also wondered if the bird landed at the moment things went south. The 220 dedicated 220 breaker was tripped, BTW.
 

johnsma22

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Did you find the circuit breaker for the pool pump tripped? It would be quite a coincedence, but if the bird happened to be sitting on the ground wire at the exact time that the pool pumps' windings shorted to ground (assuming they shorted to ground), it could explain the dead bird.
 

Fingers

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There's a thing called 'back EMF'. It's the thing that smokes a motor if the load is so high that it can't turn when voltage is applied. Normally a turning motor will oppose the voltage put to it so that it doesn't look like the dead short that it actually is. It's possible that your impeller got jammed and then there would be no back EMF and the current goes through the roof. The result is that you burn out the main coil in the motor and/or throw your breaker.
 

johnsma22

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I was answering at the same moment you answered the question I was asking. LOL!
 

Fingers

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What makes you think it was the start capacitor and not the main windings? A capacitor looks like an open circuit to an ohmmeter.
 
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I still have the old motor. The starter capacitor was what was told to me by the pool guy. There are two capacitors on the motor, on of which is mounted on the outside of the chassis. The one that "blew" is internally mounted.

FWIW, the impeller was unrestricted, the bearings appeared to have good movement.

It's an AO Smith 1 1/2 hp motor. Replacement set me back 280 bucks, but the new one is quieter. Saved the old one just because.
 

Fingers

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olllllo said:
On the bench the motor just hummed and the shaft just kind of wobbled.
Here's another theory. You have one or more coils burned out in the motor. Because of this it doesn't turn well and then you get that back EMF thing I mentioned earlier. A burned out start capacitor will make your motor slow to start and rob it of power, but it won't blow it up.


olllllo said:
Fingers... You're always around. Also good to see.
Yeah, I guess I am. I'm comfortable in the company of other beer obsessed freaks.
 

mr x

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The capacitor may have just given up the ghost. Shorted capacitors aren't that uncommon. I'd say the bird is a coincidence, but it does look strange the way it is clutching the ground wire.
 

johnsma22

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olllllo said:
Good to see you around johnsma.
Thanks! It has been awhile. I've been concentrating a lot on my other hobby lately. I'm in the middle of building a new motor for her. I haven't brewed in awhile because my biggest consumer is indisposed at the moment with a bun in the oven by the name of Kate.

Here is a photo of my Pontiac that made it into a 2008 calendar this year and a photo of my soon to be new daughter that I hope to never see on a calendar, if you get my drift, LOL!



 

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