Pool pump motor issue.

[hotrats]

I started draining some water from the pool in prepration for the upcoming tropical storm/hurricane yesterday. started draining while the pump was running, using the pump discharge. Ok, sat down, ate, took a nap, woke, remembered the pool, ran out in a panic. Pump still motor running, but the pool infeed was sucking air intermittently. Turned the pump off, closed the valve off.
This am, woke to the power going off from around 2am until 4:30. went out to drain some of the 4-5 inches of over night water accumalation. Switched the pump on, it started and immediately tripped the breaker. There is a breaker on the pool panel, and a breaker on in the main panel. The main panel breaker had not tripped. Reset the pool panel breaker, tried again, nothing.
Thinking the motor or pump froze up, disassembled enough to check, and is free turning.
Any ideas on what/how to check? Not much on electrics, although I have been 'bit' before, so learned to check that power is definitely off.

 

[Forty Niner]

Just some thoughts to ponder:
Centrifugal pumps, if it is a centrifugal pump, have an envelope (pressure and flow) that they operate best in. If the discharge has no throttling or back pressure then it would require higher amps, maybe overheating the motor. Also, when the pump is run too far out on its curve it can run out of NPSH (net positive suction head) which can result in cavitation and gassing up/running dry.. Then heat builds up because the flow is not cooling the pump. Heat can then do in the pump and motor.

 

[Alexander McGilton]

I can't tell what pump model that is, though I can say I have a fair bit of experience with Hayward super pumps 1.5 hp.

The manufacturer knows that the operators are homeowners and not pump technicians. So they under sized the impeller so they can run for hours in a less than ideal circumstance. Like the filter being completely plugged with leaves. Valves closed, excettera. Not that I'm advocating that these be abused. Only that they are rather tough units.

That said, a common point of failure is the centrifugal switch. It is intended to only provide power to the starting coils for a fraction of a second at low rpm's. Corrosion often gets this switch to become stuck on the low rpm setting, even at speed. If you provide power to the starting coils for substantial amount of time. It pulls to much power and pops the breaker. If not already burning the starter coil or the capacitor.

Try running the motor to speed and shutting it off quickly. Does it make the usual spinn down noise of the centrifuge switch lifting and dragging at low rpm? I'm willing to bet this is your problem.

 

[Ulma Doctor]

The capacitor may be part of the problem. If the motor doesn’t have the capacitor’s charge, it will have very low starting torque available. The motor will try to run on the main motor windings, which not up to the task of starting the motor under load, which increases the amps required by the motor.
This may or may not be causing the breaker to be tripped , but worthy of examination.
Make sure you discharge capacitors before you handle them to prevent injury or death.
A capacitor can be tested by use of an analog ohm meter.
Simply connect ohm meter leads to the capacitor terminals and observe the meter pointer sweep. The pointer should move if the capacitor is taking a charge from the ohm meter.
no pointer movement = failure of the capacitor

You may also wish to examine the centrifugal start switch and the rotor flyweights to eliminate concerns there.
Damaged/ haggard wires , water contamination and poor electrical connections are sources of problems too

 

[mksj]

Do not believe it has a start capacitor or centrifugal switch, just a run capacitor which is 30uF oil type. If the capacitor has gone which is more common with momentary on/off cycling, then the motor will hum and not turn, may trip the breaker. I would check the capacitor first. I always check the dimensions of the capacitor you are buying to the one on your pump, pool pumps often have smaller capacitors that can be hard to come by for the same uF and voltage ratings.
Pool Pump Run Capacitor, 30 MFD, 2444 - 5VR0303

Pool Pump Run Capacitor, 30 MFD, 2444 - 5VR0303 - INYOPools.com

5VR0303 - CAPACITOR, RUN 370V 30 MFD (5VR0303) - 2444

www.inyopools.com

How to Test a Pool Pump Capacitor - INYOPools.com - DIY Resources

Knowing how to test a pool pump capacitor can save you time and money when the pump motor fails. Every day that a pump is down, the likelihood of a lengthy and expensive cleanup increases. Troubleshooting a pump motor should begin with testing the capacitor(s). What Is a Capacitor? The basic...

www.inyopools.com

 

[markba633csi]

It really seems to me that the motor got overheated and maybe has a shorted winding
True, a shorted cap might trip the breaker, but a shorted winding definitely would
I would test the cap with a ohmmeter for short circuit
If the cap tests ok then the motor is toast I think

 

[hotrats]

Thanks for the suggestions! Well, after motor and pump apart, I pulled 6 dead lizards, and 3 huge 'cockroaches' out of the motor. Got a friend to check it, it's bad according to him. Appears the impeller has a couple small cracks, along with other areas of the housing. Seems you can buy a motor and pump on evilbay for the same or less than a replacement motor - so, that's the route I took.

 

[Nutfarmer]

It might pay to buy a variable speed pump to save on electric costs. Some areas even have rebates.