10 hp motor in the plant, you heard hum and load noise. What is the problem of the motor?
A. Open field shunt.
B. Phase to phase short.
C. Stator is shorted or went to ground.
D. Something else.....

Keny: I like multiple choice exams!

A- Open shunt field. Motor would not run.
B- Phase to phase short. OCP would trip.
C- Stator is shorted or... OCP would trip.
D- Something else....

I think the answer is D.

I would agree something else possilbly bearing failure.

Is this poly phase? Could be a single phasing motor.

Check amp draw on each leg, for premature failure and to see if motor is overloaded mechanically.

Bearing will usually be a higher pitch, than an overloaded or weakening motor.


:cool

Just some thoughts.

A- Open shunt field. Motor would not run.

DC Shunt motor with open shunt field WILL run, away that is making a very distinct sound I might add.

How about:

* E. All Of The Above
* F. All Of The Above, Under Certain Circumstances
* G. If There Was A Description Of The Type Of Motor And The Load On Shaft, Answer May Be Derived
* H. All Of "A" Through "G"

I will choose "H"!!!

Keny, is this an exam question also?
If so, what is your answer and how did you arrive at it?

Scott35