A steel bolt had been used to join the copper connecting strips between the poles of a 10-pole, series-connected, rotating field rotor of a synchronous motor. The exciting current was 155 amps. Failure of the bolt resulted in severe damage to the stator windings by the loosened ends of the strips. The bolt had fractured near the head, a location which probably coincided with the junction of the strips. A portion of the fracture surface was covered with copper that had been deposited in the molten state, while some was also present along the shank of the bolt, having...