Effects of water and oil on electric motors 1

[torqueman2010]

I have a customer who uses one of our gearmotor designs that is oil cooled. As such, the unit is sealed and filled with oil during operation. The customer is experiencing a buss overcurrent failure which I have traced to a short to ground in the motor stator. It appears that water is entering the gearmotor somehow and my opinion is that this is causing a break down of the stator's insulation. The problem is that I cannot prove this. The customer does not belive this is the cause of the problem. In fact they claim to have drained a gearmotor of all oil and filled it with water and then ran the unit for several hours with no failure. My thought is that it is the combination of the oil and water that are the problem but I am not an electrical guy and I don't know if I'm right and if I am I don't know how to explain it to other mechanical guys. Can anyone help with this?

 

[dik]

The water and oil may emulsify and the resulting fluid may be a 'milky' colour. I find it difficult to believe that the electric motor can be loaded with water... YOu might try an independent test using the same water the client has... small amounts of impurities in the water can cause significant changes...

Dik