Arcing condition possibly occurred when winding became electrically conductive
Occurring on February 9 the initial motor: Damage was reported as blown (arc damage) compensating windings, blown armature windings (reported as a “big blow hole) and blown field windings. Occurring on February 10 the replacement motor: Damage is reported as blown compensating windings (reported as “has a very large hole ”), and shorted field windings.
The main drive DC motor had the windings fault (short) to ground. This occurred again to a similar replacement motor.