Selection of brushless dc motor controller has rapid response, large starting torque, rotating speed of from zero to rated speed can provide the rated torque of sex, is the choice of many users, however, you need to know to reference the model selection of the brushless dc motor controller factors have? 1, maximum torque, can be combined by the load torque, moment of inertia and friction, in addition, there are some additional factors affect the maximum torque, such as the air gap of air resistance, etc. 2, the square torque: can approximate considered practical application need continuous output torque, is decided by many factors: the maximum torque, moment of inertia, acceleration, deceleration and load torque and running time, etc. 3, speed: this is the speed of the application requirements, can according to the speed of the motor controller trapezoidal curve to determine the speed of the motor controller needs, usually count should have 10% allowance. In actual production process, with a brush dc motor controller is high-speed motor controller, the gear tooth is small, easy to wear and tear, but strength is big, strong climbing ability. The brushless dc motor controller, in use process saves two or three years in exchange for carbon brush.