[rotorwrench]

The residual magnetism left from the polarizing of the field is what allows the generator to work up enough voltage for the electro-magnetic core in the cut out to close the switch points and bring the generator on line. If these points should get stuck together due to excessive heat or poor condition then the generator will try to motor after the engine is shut down. This will burn up the generator since it doesn't have the torque to turn the engine. It will just sit there and get hotter and hotter till something fails. The solder in the armature will usually melt first.

Original cut outs may have the cap spot welted on from underneath. The spot welds can be ground till the cap will release. With the cap off, the points can be dressed and the magnetic pole condition can be evaluated. These cut outs can be repaired as long as they aren't toasted.