Monday, September 21, 2009

Moved Courses, Ready Once Motor Is

Saminco sent out a service tech and replaced the broken IGBT in our inverter and reassembled it. That part of the driveline is now good. We took the motor to CW Silver in Salt Lake City where we opened it up and found wires that had been burnt through by the carbon windings on the motor's rotor. The cause of this is still being worked out. Below you can see the stator and a closeup of the location where the carbon fiber is shorting from rotor to stator.

In the mean time, we moved our pits to right next to I-80 in preparation for when we receive the motor back. Since we have some down time, we are getting some photography and "extra" projects out of the way.


KeithG said...

This happened to us in Cleveland 1995. Overnight rewind and we were able to start. If I were a betting man, I'd bet that you had a short which caused local heat and expansion which caused the rubbing.

Is it VPId? It looks like loose windings instead of all encased in epoxy. That could just be due to the picture resolution, though.

jcKeller said...

I'm with Grider.

Surprised by what appears to be relatively "loose" end windings. Are you sure this is rotor to stator arching? It looks like thermal stress and/or standing wave issues with these stator end windings. I would VPI the entire stator and shorten up those end routings...realize this is a photo and only seeing half the motor!!

In industrial applications I am familiar with, the un-VPI endwindings were VERY typical failure sites, particularly on inverter controlled motors. Several issues, but in the end VPI and tight control on winding processes solved problems. Local heat stress (due to environment - have dirt and sometimes moisture buildup in those open sites breakdown the insulation over time; also had transient currents and coronal discharge in endwindings).

Good Luck Buckeyes!!

BSEE 1995