Smeg fan motor trips RCD - How can I test?

[newbornmole]

My smeg A42 range has been tripping the house RCD recently when turning the main [fan] oven off.

Trial and error has led me to find that that if the fan motor is physically disconnected then the above fault does not happen. As soon as I reconnect it will trip again as soon as the oven is turned off. Someone has said that I must not disconnect the fan for long or the element will burn out.

Does anyone know a test I can do on the motor to prove that it is the motor causing this. I have a bog standard multimeter. (AC, and OHms).

Or can anyone think of another reason for this?

Thanks in advance

Stuart

[Ian Stirling]

Measure from each side of the motor connections to its frame. It should measure infinite resistnace (keep fingers out of the way). However, passing this test does not mean that it's OK.

[newbornmole]

Thanks Ian,

Should I do this test while the motor is running?

[murrietalker]

I think it would be advisable for you to get a service engineer in !

[Ian Stirling]

Err, no! Disconnect it, and do it while it's NOT live.