Pump Motor running hot and hesitates when starting

[PoolDoc]

Pump has started to hum for about 3 or 4 seconds when I turn it on before it kicks in. I also notice that the body of the pump motor is very hot.

The pump may not be any hotter than usual -- you may not have checked before.

But, the hesitation on start often indicates some mechanical aspect of motor and impeller is not turning freely. There can be a couple of causes, but in my experience by far the most common cause is worn bearings.

A weak start winding or start capacitor (may not have either -- don't know what motor you have) could also cause a slow start, but usually it would be slowly, the same way every time.

Motors can be rebuilt, but replacing the motor is a 'cleaner' fix if you can do it. Also you may not have a rebuilder in your area. If you get a new motor, be sure to also get a new seal and any new gaskets / bushings / washer that are long the path of the motor shaft.

PoolDoc

[gottliebo]

It's an A.O. Smith motor (Sta Rite Pump - see above) and yes it has a starting capacitor. I assume those can be tested somehow. There's a danger with capacitors I believe because they hold a charge and need to be shorted with insulated screwdriver before being touched, right?

If it is the motor and not the capacitor, should I just look for an identical replacement or are there more efficient and reliable bands that you would recommend? Or, is nine years not all that unusual for a motor to begin to fail?

Thanks!

Tom

[PoolDoc]

A 9 year old motor? Yeah, that's getting to the outer end of the life expectancy for fractional motors like that. I probably wouldn't rebuild it.

Like I said before, if it was the start capacitor, you'd see the same failure every time, so that's not it . . . or at least, that's not the ONLY problem.

I'm sure there are quality differences between motors, but I wouldn't know how to evaluate them. And the motors are redesigned so often, the 'best' motor could change from year to year.

If your pump is on a lot, I would look for a high efficiency motor. You can compare apples to apples -- if you are comfortable with the tech level -- by matching RLA (Run Load Amps) at equal voltages for given motors. But to do so you must match S.F. (Service Factor) values. High efficiency motors will show lower RLA values at a given voltage, HP, and SF. If this is all goobledy-gook to you, you'll need to match motor to model and simply pick the Hi-E motor if it's a reasonable price difference.

Good luck,

Ben

[Poconos]

Hi again Tom,
Ben has a point about checking the temp. Many people never think to put their hand on it unless they suspect a problem, then it feels really hot when it could be simply normal for that motor and load. The fact it doesn't hesitate every time kind of confirms my suspicion about the starter switch contacts. A motor on my bandsaw went through that phase of having to smack it to get it going 'sometimes'. Finally got to cleaning the contacts and fine ever since. Usually those contacts are behind a cover that allows access to the wiring terminal board. Try cleaning them with 600 grit paper. Auto stores, Home depot etc. If you can get a thin, flat file in there all the better. dress the contacts lightly as they are usually silver and soft. While you're in there check for any loose wiring contacts too. Hope your problem is this simple.
Al