April 2020 SARebuild 18 Traction Motor

28 MAY 2020 After the last motor problem I have modified the armature shaft replacing the inner stupid circlip with a steel sleeve spacer for the 50/90 x 30mm bearing. The aim of this is to limit the end float.
Mods to the gearbox casing are to drastically increase cooling air flow.

 This rotates at 6000RPM at 60MPH

 Running a constant 55MPH causes an unintended pumping effect in the gearbox. This eventually pumps all the oil out to the near side wheel the gearbox will eventually run dry!

 Mods to the field winding are to thoroughly clean it with white spirit - dry it then saturate it in clear varnish - something the manufacturer didn't do for some reason

 Tape up the field winding wires to help pull them through - helps re assembly

 50mm thrust washers replace non extant thrust washers in the original

124024 miles. Another breakdown on the M4 East J6 I'm sorry to report. I was in the section without hard shoulder when the motor again cut out! I needed to call the AA for emergency recovery. (it took 4 hours) 30-1-2020
When I got back I removed the motor again and pulled off the ends. The circlips restricting the armature shaft end-float had worn away a section of the shaft allowing the windings to come into contact with the gearbox casing. This shorted the armature windings destroying them!

Brush holder worn away due to armature end float