Electric motor runs when HP option not selected.

[Jeff_L]

When a customer is finished using a HP option, I noticed the electric motor continues to run for about a minute longer, it does stop. Even when the customer is using a LP option, or the timer has expired. The water valve closes like it should, so there is no water running through the pump, but the electric motor keeps spinning. It does stop after a minute or so. Is this a sign that the timer is going bad?

 

[MEP001]

Not likely the timer, since it controls power to everything and not the motor alone. That's controlled by the switch. What type of equipment and bay controls do you have?

 

[dustpan]

Could be the motor starter contactor sticking, could also be a low pressure function is programmed as a high pressure function.

 

[Jeff_L]

MEP, it's a standard 20+ yr old setup. 8 position rotary switch connected to a transformer then to a contactor. Electric motor is a Weg and the pump is a Hypro. Pretty easy setup. I would agree that it looks like the contactor is sticking, but it doesn't take anything to "unstick" it. It'll release itself after a minute or so. Seems like something is keeping the magnet energized. Just need to find what is making it continue to run a little longer. I'm afraid it'll wear out my pump since the water valve closes at the end of the timer as it should.

 

[MEP001]

Check for voltage at the contactor - if it's just sticking, you'll read none on the contactor coil.

Does the motor still run if the timer runs out of time?

Some older washes had start/stop buttons, and even though they were removed, the relays that controlled the pump stayed. The way most of them worked back when the Oak switch was used was that the timer was connected directly to the motor and would run through two or three relays. When any of those relays were energized by a low pressure function it would break the circuit to the motor. If, for example, the tire cleaner output from the switch was bad, it wouldn't kill the motor.

If you could take a few pics of the pumpstand's wiring and maybe the meter door's backside and upload them here, it might be helpful.

 

[Jeff_L]

I'll check the voltage today and see what it reads. Yes, the motor continues to run for about a minute after the timer runs out. Kinda odd huh?

I'll also trace the wires back to see what they go to, relays and such. I'll also look at uploading some pics.