Cleaner motor hums - runs then trips

[wbnethery3]

Hey all,

My Pentair 3/4 hp cleaner motor is malfunctioning. This problem started a couple weeks ago and I've been too busy to work on it until now. I just disabled the cleaner cycle since the pool is covered with a leaf net right now.

The motor hums and won't run, then within 15-20 seconds trips off. It doesn't trip a breaker, but I guess the internal thermal overload takes it out. After cooling off, it tries running again and the same results repeat. I can rotate the shaft by hand with no problem. I searched here for "motor hums" and found multiple posts concerning the capacitor. I pulled mine and tested it with a multi-tester, seems like it behaves as a "good" capacitor would. Without using a capacitance tester, I can't be certain - it just starts at low resistance and builds up as it collects charge. This tells me it isn't shorted. When I try spinning the shaft while the motor is humming, it will run for about 15 seconds, then trip just as it does when started from a dead stop.

I also tried rapping on the sides of the motor while it was humming to see if that helped. It didn't make any difference.

Is this a bad motor or is the capacitor just weak?

Thanks in advance - you guys are great assistance.

 

[bobodaclown]

Without power does the shaft turn smoothly? (checks bearings/makes sure impeller/shaft isn't jammed)
What's the age of the motor?
I'd try a replacement capacitor first, $20 or less.

This being a cleaner motor I'm assuming a booster. Does your main have to be on?

 

[wbnethery3]

Yes, as stated, the shaft turns freely and smoothly. The pump is 6 years old, original installation with our pool. It is a booster which requires the main be running in order to start. No issues with that circuit. I can replace the capacitor, just rather not spend the money if someone here can tell me the symptoms are consistent with a different problem.

Thanks!

 

[bobodaclown]

I'd go with the capacitor.
This link may help: http://www.youtube.com/watch?v=ZEIv5ClLqXg

 

[wbnethery3]

Have located a replacement, mine is even easier to replace than the one in that video. Hoping it does the trick. BTW - the quality of that video was pretty poor, and the comments were hilarious... there are gazillions of videos on the same subject, I found one that was very similar to mine and realized it was too easy and cheap to not try first.

 

[wbnethery3]

Well, the capacitor was NOT the problem. Replaced mine with a brand new one and the symptoms are identical. Motor hums when started, shaft will spin for a few seconds if started by hand, then it trips. This sounds like it must be a bad motor, but I haven't had a chance to pull it apart and inspect it yet. Was really hoping the capacitor was the fix... oh well, so much for cheap and easy.

 

[JamesW]

If the voltage is correct, then you probably have a bad motor, especially if it's old.

 

[midtngal]

I have had this same issue several times myself. I learned that there is such thing as a bad capacitor. They're about $7 where I get mine ao it's well worth trying one or two more before you get a new motor. I've had it turn out that the next one worked and I've also had it work out that I did indeed need a new motor!

 

[wbnethery3]

Well, since I tested the first capacitor with a multi-tester and it wasn't shorted, and the new one did basically the same thing when installed, I'm pretty sure the motor is shot. I suppose after 6 years of daily use, it's not that surprising. I don't have access to a limitless supply of capacitors, and with most electrical items they won't let you return them once you've installed them because it can't easily be determined whether you ruined it or it was bad to begin with.

I consulted my local pool supply about a replacement motor and they say a new pump assembly will be cheaper... had a friend confirm with a quick internet search. Not the news I wanted to hear, but it is what it is. Almost time to start-up the pool, so I need to get this done.