The YR wound rotor induction motor soft starter (slip ring motor) JR JZR, YR, YZR, three-phase wound rotor AC induction motor (also known as slip ring motor). Its rotor external resistance or reactance, high power factor and high starting torque at start, in the fields of metallurgy, machinery, chemicals, mining, building materials commonly used in this motor to Drag the device. Slip ring, carbon brushes, short-circuit ring is mounted on the motor shaft parts, and the relay in the control box, AC contactor, frequency sensitive rheostat and other electrical components to form a complete secondary loop system, as a motor shorting means for starting and running. This way of working of the motor has the following disadvantages: 1, carbon brush is easy to wear, high consumption, the amount of maintenance, and affect the normal production. Between brush and slip ring is easy to produce sparks, some places can not be used. 3, brush and slip ring friction, increasing the contact resistance, the motor temperature rise. 4, conductive powder is easily inhaled inside the motor and is a serious hazard of burning motor. 5, the time relay runaway easy to burn out the AC contactor and frequency sensitive rheostat, resulting in downtime discontinued. Dedicated WZR controlled brushless motor starters just to overcome the above shortcomings. It eliminates the need for slip rings, carbon brushes and secondary loop system, no spare parts, reduce the amount of maintenance, to ensure the safe operation of the motor, once installed, the long-term benefit, is in a leading position in the starting equipment. Brushless motor starters it works: dedicated brushless WZR-controlled motor starters is evolution the BP4-frequency sensitive rheostat work, it uses the best magnetic circuit principle and best magnetic material the original secondary loop system multi-touch point electromagnetic circuit components, process innovation made a non-contact electromagnetic components, variable resistance as a startup starting equipment. It by the motor during starting, the rotor current frequency with the rotor speed increases and reduces the relationship, i.e. the rotor speed changes from 0 to the nominal rotational speed Ne, the rotor current frequency from 50 Hz to smoothly reduced to l-2 Hz, STARTING impedance by the maximum displacement to a minimum, equivalent to the resistance of the rotor circuit external from maximum to minimum, it can be automatically attached to the rotor frequency change for smooth adjustment, it is an ideal starting device. Installation and maintenance: 1, first remove the motor shroud, slip rings, carbon brushes, brush box, brush box bracket and short circuit ring device (some motor short-circuit ring device), and all other parts. Demolition of slip ring, to prevent later wiring errors, the same two wires should be tied together. 3, with a vernier caliper, measure the motor shaft diameter and pore size of the starter, key pitch, the key to higher dimensions are the same, if any difference, with the company in a timely manner, in order to solve. Lightly grease or oil on the shaft keyway alignment of the starter shaft key, and then copper rod starter gently tap to the assembly position, and stuck with a wire ring to prevent starter axial move. 5, assembly, should not knocking Cookin, so as to avoid damage to internal parts or leaking. After the initiator assembly is completed, will be transferred to