Z4 DC motors are widely used in metallurgical rolling mills, metal cutting machine tools, papermaking, textiles, printing, cement, plastic extruders and other industries. It is suitable for occasions that require a wide speed regulation range. The electric drag overload capacity does not exceed 1.6 times, and the constant power weak magnetic upward speed regulation range can be 1~3 times the rated speed according to different specifications. The constant torque is reduced, the armature voltage is reduced, and the speed regulation can reach 20r/min. It can be powered by both DC power supply and static rectifier power supply, and has small inertia, good dynamic performance, and can withstand large rated loads. It is particularly suitable for control systems with stable speed regulation, high efficiency, automatic speed stabilization, and sensitivity, and has reached the international advanced level.