Strange breaker tripping issue with A.O. Smith 1hp

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slogu

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Jun 20, 2011
13
Pump: Jacuzzi Cygnet 2
Motor: A.O. Smith 1hp wired for 230v production date in 2008 bearings replaced in July of last summer.

I had experienced a tripped breaker a couple times at the end of last season (September) so I figured I'd start early this year to get my issue resolved. I moved into the house a year ago so I have made no changes to anything.

My breaker trips at the main panel, not the sub panel. Only the pump and my light are on this circuit and the trip happens with the light off as well. The breaker trips randomly but it wont run any more than about 2-3 hours. So I started my diagnosis and I'll let you know what the results were.

Power on, Motor running = Tripped breaker at main panel
Power on, Motor non running = Tripped breaker at main panel
Power off at sub panel, but on at the main panel = No tripped breaker

So at this point it was pointing to the motor so what I did was totally un wire the motor from the sub panel and here is my result:

Power on, Motor disconnected and pool light on = No tripped breaker after 3 days

I think its pretty clear my problem is in the motor somewhere but I just want to be sure before I replace it entirely. I think its very odd that the breaker still trips with the motor connected but is off.

I wanted to get some insight on this and any help or recommended "tests" would be very helpful. Thanks in advance!
 
When the motor is off, are both 230v leads disconnected or only half the circuit? (If both disconnected cannot be the motor)

Is the breaker in the main panel is a GFI breaker? (these can go bad)

Do you know if the motor has a centrifugal switch? (possible short)
 
The motor has 3 wires coming into the fuse box. I have the black and white disconnected with the earth still hooked up. Im assuming both of the 230v leads are disconnected as the breaker for the pump at the sub panel are 2x 15 amps tied together. Not sure if the breaker on the main panel is GFI or not. Not sure if the motor has a centrifugal switch either.
 
"Power on, Motor non running = Tripped breaker at main panel"

In this situation, how are you turning off the motor and are both leads disconnected?
 
I am still a little confused, you are using a timer to turn off the motor? Does the timer actually disconnect both leads to the motor?
 
Yes I use my timer to turn the motor on or off. When I say I have disconnected the wires I mean that I have physically unwired them. So power on motor not running is with all connected and breakers hot but switch is off. When I said power on motor disconnected i mean power is on, switch is on, and the wires are physically unhooked. Sorry for the confusion.
 
But I still need to know if the timer is setup so that when you flip the switch on the timer it actually disconnects both leads to the motor. Some timers are setup to disconnect only one side of leads. If the timer disconnects both leads to the motor but the breaker still trips, the problem is likely in the timer and not motor because it is disconnected by the timer.
 
OK I see what you are saying now...I will have to check when I get home. But if it were in the timer wouldn't it trip the breaker regardless of the motor being connected or not? And just to clarify the motor only has 3 wires coming out of it. Black white and copper. I disconnected both the white and the black from the timer itself.
 
The timer is probably setup with only one lead on the switch, otherwise it wouldn't trip the breaker under the scenarios you are describing. For safety reasons, a timer should be setup to switch both leads on a 230v service so as a separate issue, that should be changed.

So if at least one lead is connected when the timer is switched off, it is likely to be the motor as you first suspected and it could be either the centrifugal switch in the back of the motor or perhaps the capacitor. If you don't have experience working on motors, you could take it to a motor shop have have them test it.

Also, it could still be a GFI issue so check both breaker sets to see if they are GFI.
 

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slogu - why don't you describe how your pump is connected up - start at the main panel, on out to the pump. Describe each component - wires (colors, wire size if you can), amp rating of any fuses/breakers, whether they are 120V (single pole) or 240V (double pole) and whether any breakers are GFCI (usually have a button that says "TEST"). Include any subpanels and timers / switches (and whether they are single or double pole).

From what it sounds like so far - you probably need to have your motor looked at, or maybe replace your pump.
 
Ill do the best I can without having it in front of me. I can update wire colors when I get home. Main panel has 2x 30a breakers tied together hooked up to a piece of outdoor wire which has 4 wires in the casing. this is through conduit on over to the subpanel about 25ft away next to the pump. they run into the sub panel box and there is 2x15a breakers tied together for the pump and a seperate 15a breaker which is for the pool light. None of the breakers have a "test" button on them but there is a GFCI outlet ran off of the light breaker which seems to work fine.
 
Ok - so no 240V double pole GFCI - not good (for people safety), but considering the cost of them (my GE panel 20 AMP GFCI breaker cost me $100 - and it's one of the cheaper ones !).
Your subpanel wiring is probably copper (or green) for ground, red and black Hot conductors, and a white neutral conductor. Red and black from the main goto a main breaker in the subpanel, White goes to a neutral bar, and ground goes to another ground bar. This subpanel should have 3-4 breakers - 1 double pole 15 AMP breaker going to your timer and on out to your pump, at least 1 15 or 20 amp single pole breaker for the light and the GFCI outlet .

Your timer should have at least 3 conductors - 2 hots and ground - both in to the timer and out to the pump motor. If you put a voltmeter going from red to ground or black to ground - they should both have the same voltage (around 120V). If the timer is off - both should read 0 volts.

I would suggest you have an electrician checkout the power side to the motor connection, and a motor shop check out the pump.

And please don't take this personally - I don't want you or your family to get a nasty (potentially fatal) shock. I had my own pool pump wiring hazard that I took care of last summer - mine was uglier than yours.
 
Your description of the wires sounds like a 120 setup. Is the copper one bare all the way? If so I am not sure how that could be wired for 240 even if the white was used as one of the legs.

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Small update:
The timer switch poles both read at 120v on the white and black when on and both are at 0v with switch off. Last night I bypassed the timer and ran power directly to the pump. The motor ran all night without issue. And is still running. The timer is an older Intermatic with the yellow dial. Are these known for any issues?

It may have been rewired....I know the pump has a sticker that says " this pump has been factory wired for 230v " but it is possible that someone changed it. The ground wire is bare with no insulation.
 
Did you read between the white and black? If it's 240 then it should read 120 to neutral (or ground) from each wire and 240 between them. If it's 120 then it'll read 120 between them and 120 between hot (black) and ground and zero between neutral (white) and ground.

We haven't heard of many problems with the Intermatic timers, but like all things electrical, they surely can have issues.

Can you post a pic of the wiring inside the timer?
 
I was getting 120 between ground and both wires. I did not check the voltage on black and white together. I'll do that when I get home. I can snap some pics as well.

At this point its looking like it has to be the timer as that is the only thing I have bypassed right now.
 
Would it be possible that perhaps my timer is causing additional draw on the circuit and it actually is the motor failing but without the timer hooked up the motor alone isn't enough to trip?
 

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