Starter/motor Reset

[Dolfan]

Good afternoon to all my northern cyber lectricians. I have a question about a square D starter/motor I replace for a 5 hp irrigation motor. It's controlled by a pressure switch that normally works well during the week, according to the maintenance guy. He says that he has to push the restart button at the beginning of the week to get it to work normally during the week. I checked it out and found nothing to be wrong electrically. Is there a setting on the pressure switch that needs to be adjusted or what.

 

[hurk27]

Is this a 3-phase installation?

If it is, could be a case of intermittent single phasing, look for dirty contacts, loose connections, and could even be a utility connection from the pole.

recorder is the only way to be sure, you should be able to see which two heaters kicked out, which will show the faulty phase (the one that didn't)
it can even be a proble with the motor.

If only one heater kicked out, then this points to a short/ bad winding at the motor, if all 3 heaters lick out, then it sounds like a motor over loading problem, like maybe when it sucks up some solids?

 

[RichB]

What hurk said---Also I would look into what is happening on the weekends that ISN'T happening during the week--But a recorder is really the only way to see what is happening on the line.

 

[Cow]

I'd meg it and amp it, check the amps against the nameplate. Check voltage on the bottom of the starter with the motor running. I'd also take a look at the starter contacts and make sure the heaters are sized properly. Maybe even clean the rust off the coil faces while I was in there if it's removable.