DC motor rotor failure

[elinBG]

What is the cause of this failure?

Thank you!

http://www.eldvigateli.com

 

[nic00b]

Good afternoon elin,

Why was the brush grade changed from 283 to 571, has the maintenance regime altered to suit the possible change in brush wear?

What kind of application is the motor used?

Do you have any PCM (plant condition monitoring) on this motor?

 

[elinBG]

Hello,

The brushes were changed because of the manufacturer send this brushes saying that they are the correct ones.

The machine is kind of extruder, where 4 motors work in parralel.

I am not sure what exactly do you mean by PCM, but even if it is available we cannot use it, because the motor failed, isnt it?

When we bringed the motor they said that it worked fine in the last month. Suddenly it started overheating and until the engineer go to see what is happaning, the excitation winding failed to ground and the motor was in the conditions from the photos.

http://www.eldvigateli.com

 

[Skogsgurra]

The condition monitoring supervises vibration, temperature and such things. You can read what happened before failure from it and is quite useful. Not so common in extruders but lots of them in paper and steel and other continuous processes.

I asked about ventilation earlier. Is the fan working, are the vent ducts in place, are louvers open, is there an air flow switch?

Gunnar Englund

http://www.gke.org

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Half full - Half empty? I don't mind. It's what in it that counts.

 

[ozsalty]

Looking at the sequential burn marks on the commutator in your first post,I would say the leads have been layed down in the incorrect order.What was the commutation like under load?...There must have been some unusual sparking there..

 

[nic00b]

What has the commutation been like on the motor prior to the 'fault'?

Has the motor been running hot?

Are you sure you don't have an earthed interpole?