Another bad pool pump motor

[mark32]

Hello, a neighbor asked me to check his pool pump motor last night because it's overload would trip after running for 10 seconds. The motor is shot (It's pulling 25 amps instead of the nameplate of 7). Everything seems to check out okay but this is his third motor in four years. The only non typical arrangement he has (To these eyes) is other pool associated components being fed from the pump's timer terminals, both line and load. One component somehow chlorinates the water by way of some electronic device that's installed in the plumbing of the pool. The other component seems to monitor flow meters or sensors that are also installed within the plumbing, of course. Anyhow, one of the components is sending 120 down on one of the motor leads at all times. I don't think this would cause any damage to the motor but three motors in four years is strange. Any suggestions?

 

[tshea]

How far is the pump from the power source? You may be experiencing voltage drop problems.
Check ALL wiring from power source to pump. Might have intermittant/ loose/ corroded wiring.
Is water getting inside motor?

 

[mark32]

tshea, thanks for your response. The voltage checked out good and I didn't see any water inside the motor's wiring compartment. I did check the connections in the timer but not in the disconnect that feeds it, nor inside the main panel.

 

[ramsy]

..trip after running for 10 seconds. ..pulling 25 amps instead of the nameplate of 7. ..third motor in four years. ..associated components being fed from the pump's timer terminals ..one of the components is sending 120 down on one of the motor leads at all times.

Try putting the motor on its own circuit. (ie) temporarily on a cord. That way you can eliminate a problem with the pump vs one of those circuit components.

Feeding the motor phase-to-phase is a good way to reduce voltage drop & eliminate problems with shared neutrals anyway. In commercial locations phase-to-phase motors also help reduce motor overheating from zero-sum noise found on neutrals, but not positive or negative-sequence noise found on phases.

Iduno if a few SCR sensors, or rectified-flow meters produce much noise, or how much noise it takes to smoke a motor in 3 months, but an RMS clamp could measure any current imbalance, noise, between the circuit's shared neutral and phase. The phase-to-phase setup would eliminate most of these problems anyway.

 

[bphgravity]

Is it possible that the motors are dully rated for both 120V and 240V and the wrong wiring configuration has been connected? If you are sending 240V to a motor factor configured at 120V that would cause similar problems.

The other device you are referring to is a "salt-water chlorinator". The device works by making its own chlorine for swimming pools by converting mild saline pool water (about 1/6th the concentration of seawater) into chlorine. Basically you dump a bunch of salt into the pool and let the machine do its work.

The device connects to an electrode connected in-line with the pool water pump. The electrolysis splits the salt molecule (sodium chloride) into sodium and chlorine. At the same time a hydrogen atom is freed up from the water molecules. This produces sodium hypo chlorite (liquid chlorine) for your swimming pool. Sodium hypochlorite is chlorine in a usable form, which purifies and sterilizes the pool water.

 

[mark32]

Thank you all for taking the time to write. Bryan, I did in fact check to make sure the motor was "Set" to the proper voltage setting, in this case 230. By the way, your explanation as to the workings of that salt-water chlorinator is brilliant. I didn't know anything of the sort even existed.