In a shunt DC motor, what are the sequence of events when the field current is lost?
From what I understand the loss of the field current, and thus the field itself, will result in a decrease in back EMF on the armature. This will allow a higher current to flow through the armature, and also cause the motor to speed up.
My question is, if the field current is lost through an open circuit and there is no field will the back EMF drop to zero? And how quickly will the armature current thus increase to the limit imposed only by the DC resistance of the wires, matter of seconds or milliseconds?