Dc motor controller of the cause of the light did not turn

For dc motor controller, if the light does not turn, need everyone to find the root cause, and then targeted to solve. Below small make up to you to introduce the cause of the light did not turn. 1. Because of its armature circuit break line, so cause the light did not turn. 2. Because of its armature coil short circuit, so cause the light did not turn. 3. Because of the vertical of the commutator board or and head to take off the welding, so the light did not turn. 4. Due to the excitation circuit disconnection, so cause the light did not turn. Above is the light did not turn a dc motor controller in root cause analysis, hope to help everyone.