The working principle of the brushless starter motor during starting, its resistance is a variable, you can increase or decrease with the rotor current frequency is proportional to the size of the cases, the starter coil winding, inside and outside the core, front and back yoke plate, sleeve short tap and other major parts to form a circular reactor, the starter is mounted on the motor shaft, the use of the motor during starting, the rotor current frequency fz is with the rotor speed increases to reduce the relationship, the rotor speed by 0 to ne, the rotor current frequency from 50Hz to smoothly down to 1 Hz, the starting iron loss from maximum to minimum, maximum resistance also becomes equivalent to the rotor circuit external to the minimum, it can automatically with the change in frequency of the rotor for smooth adjustment. When the motor speed is close to the rated speed, short tap inertia force the starter automatically shorted, does not require any auxiliary electrical components, a good solution to the loss of the rotor temperature rise, the load current relatively high due to all the implications. When the motor reaches the rated speed, without the use of the starter, the the shorted device will coil winding automatic disconnect, not only saves energy, but not heat coil winding to ensure the stable operation of the starter. Its advantages are: remove the slip ring, carbon brushes, brush box and short-circuit ring, remove the secondary loop systems in the frequency sensitive rheostat, AC contactors, time relays and other components, in the brushless motor loop operation based on the real to maintain the original operational characteristics of the motor, which prolong the life of the motor at the same time, also to ensure that the service life of the starter itself. Controlled brushless vacuum motor starter is bound to excellent starting performance, low price, power supply and load adaptive capacity, small size, energy efficiency and running easy maintenance, etc., to obtain a wider range of applications. Scope: Where the original resistance starter, reactors, frequency sensitive rheostat, liquid rheostat starters, soft starter starter JR, JZR, YR, the YZR three-phase wound rotor AC induction motor (variable speed, air intake the exception of the camera) can be selected and controlled brushless the vacuum motor starters "to replacement, with motor capacity 15-125KW. Drag equipment such as ball mill, crusher, fans, air compressors, pumps, conveyors, rubber mixing machine, hypoxia machine, mill regardless of the positive, occasionally with frequent start will not affect.