JR, JZR, YR, YZR, three-phase wire-wound rotor induction motor (also known as slip ring motor). The external rotor resistance or reactance, high power factor and starting torque in the fields of metallurgy, machinery, chemicals, mining, building materials commonly used by such a motor to start Drag the equipment. Parts, equipped with a slip ring, brush, and short-circuit ring on the motor shaft in the control box relay, AC contactor, frequency sensitive rheostat, and other electrical components to form a secondary loop system, as motor starting device and run short. The motor of this work has the following disadvantages: 
 1, the carbon brush is easy to wear, high consumption, maintenance of large, affecting the normal production. 
 2, between the brush and slip ring is easy to produce sparks, some places can not be used. 
 3, the friction of the brush and slip ring, increases the contact resistance, and motor temperature rise. 
 4, conductive powder is easily inhaled inside the motor is a big hidden burning motor. 
 5, time relay, AC contactor out of control is easy to burn and frequency sensitive rheostat, cause downtime discontinued. 
 Advantages 
 The starter uses brushless loop-free operation, simple operation, easy installation and removal, can significantly reduce maintenance costs. According to mechanical load characteristics, automatically change the size of the starting resistance, adjust the starting torque and starting current, the motor is the best starting state. 
 Dropped from 7Le 1.6Le, the starting current to keep the motor starting torque constant, and maximum torque starter motor. It evolved resistance starting device has the following innovation: 
 A brushless fluid resistance vacuum motor starters complete eradication of the use of slip rings, the hazards caused when the carbon brushes. Get rid of the traditional, complex starting device, easy to operate. Can greatly reduce maintenance costs. 
 2, to save installation space and the secondary circuit cable, reducing the power consumption of the starting device, and saves energy. 
 3, the start control motor torque is done automatically by the starter. Completely avoid the other starting device not according to the size of the load, automatic tracking 
 The motor was a result of the negative phenomena such as motor or starter damage. 
 4, the motor is running the process, such as the stall phenomenon. With the reduction of the motor speed, the starter will be automatically put into operation, to increase the motor torque, reducing the starting current for the purpose. 
 , To overcome the stator control motor soft starter starting torque and starting current is proportional to the square of this defect at the same time reduce the motor starting current to increase motor starting torque and maximum torque starter motor, no- run the brush to remove the traditional, cumbersome, multi-touch components starting device, the base starting device power loss and the motor starting time more than 10 times less than the stator control motor soft starter, the starter price is less than other soft starter 1/3. 
 6, the starting resistance be installed directly on the motor shaft, the centrifugal force generated when the motor rotation as the driving force to control the size of the resistance, to reduce the motor starting current, to increase the starting torque to achieve the purpose of running brushless self-control. 
 7, anti-rust, anti-deterioration, freezing (the freezing point of -40 degrees,), anti-boiling (boiling point of 120 degrees), four anti-starting fluid, to improve the service life of the starter. 
 8, set the safety vent valve, automatically opens the exhaust valve to ensure safe and reliable operation of the starter motor speed reaches the rated speed. 
 Scope of application 
 Supply voltage: three phase 50HZ 380 ~ 10KV; starting frequency: per hour more than 10 times; 
 Motor: three-phase wound rotor induction motor; Altitude: not more than 2000M; 
 Ambient temperature: the lowest temperature of -40 ° C, maximum temperature of +40 ° C; non-flammable, explosive, without serious corrosive gas.