(1) Overvoltage protection: an armature circuit protection using an overvoltage relay;
(2) Zero-excitation protection: protection by excitation circuit composed of current relays;
(3) Overload protection of DC geared motor: an armature circuit protection using current relay;
(4) Overcurrent protection of DC geared motor: protection of an armature circuit composed of overcurrent relays;
(5) Grounding protection: The grounding protection formed by the voltage relay is used. When any point of the DC geared motor is grounded, the voltage relay operates, and a warning signal is issued or the power supply DC geared motor is cut off.