motor repeatedly shorting
motor repeatedly shorting
(OP)
hi,
can somebody help me here? my 5hp 3600rpm weg brand HCL pump motor repeatedly shorts to ground. i have had to replace the motor 3 times within the past 5 months. i have been using weg brand motors elsewhere in the plant and they have proven to be reliable.
besides the motor running under water, what else could explain the frequent shorting to ground?
also, even if water were to get into the motor would the motor not continue to run as long as it was not shut off?
thanks for your anticipated help.
kwame
can somebody help me here? my 5hp 3600rpm weg brand HCL pump motor repeatedly shorts to ground. i have had to replace the motor 3 times within the past 5 months. i have been using weg brand motors elsewhere in the plant and they have proven to be reliable.
besides the motor running under water, what else could explain the frequent shorting to ground?
also, even if water were to get into the motor would the motor not continue to run as long as it was not shut off?
thanks for your anticipated help.
kwame





RE: motor repeatedly shorting
If water gets in your motor, your done. Most of submersible motors are filled with oil and any water present will out the motor. There are probably some important installation notes to follow when installing these. I have installed some larger 3 phase motors and you always have to top them off with oil when installing. Yours may not be the same. Perhaps water is getting in during the installation some how (assembling pump and motor during installation).
RE: motor repeatedly shorting
1) weg has changed to a different offshore supplier.
2) Change to a different motor supplier; easy if the motor is a standard NEMA design.
RE: motor repeatedly shorting
Eng-Tips: Help for your job, not for your homework Read FAQ731-376
RE: motor repeatedly shorting
sreid, it is too early for me to accept that weg is putting out bad product because during this same period, i have installed several weg motors elsewhere in the plant and not had any problems at all.
jraef, my motor is not used in a submersible application, except that water levels in the dike where the pump is located sometimes tend to be too high. but even that other weg motors at similar heights in the same dike don't seem to budge.
RE: motor repeatedly shorting
These systems have no enforced voltage to ground so whatever touches them is transferred to the load.
On the other hand, if your source is grounded center wye, the voltage is fixed by the transformer windings and will not change without releasing a fuse or circuit breaker.
RE: motor repeatedly shorting
Even if we assume that water is not getting into the connection box, non-submersible motors use cheaper winding insulation that is, to varying degrees, hygroscopic, meaning it absorbes moisture. When a motor gets that wet it is very important to thoroghly dry it out before energizing it because any remaining moisture can vaporize behind the winding insulation and cause it to bubble up, eventually failing. The fact that your other motors have not done this can be attributable to luck, or perhapse there is some difference in the operating sequence so they have more time to dry out before being run again next time, compared to this one.
Eng-Tips: Help for your job, not for your homework Read FAQ731-376
RE: motor repeatedly shorting
RE: motor repeatedly shorting
P
ick a motor thats correct for the application or come up with some way to protect them from moisture.
So is the water submerging the motor partially or is it just splashing water? Either are bad for standard motors.
Expect to have more failures until you pick one for the application.
RE: motor repeatedly shorting