How may temporary repairs to an open DC propulsion armature coil be made, allowing continued operation until permanent repairs can be made?

Correct Answer: Option D — disconnecting coil ends, insulating each, and short circuiting the two commutator bars

To bypass a faulty armature coil, the ends of the damaged coil must be disconnected and insulated to prevent shorting to the frame. The corresponding commutator bars are then short-circuited with a jumper, effectively completing the circuit path and allowing the motor to operate temporarily until a permanent repair is performed.