When to use a reducer for a brushless stepper motor

The power of the brushless stepper motor is connected to the brushless motor through the controller, so that the brushless motor can run in one direction. From the perspective of the direction of motor shaft extension, clockwise rotation of the motor shaft is called forward rotation, and counterclockwise rotation is called reverse rotation. In the following two situations, brushless motors need to consider the adjustment of the motor rotation direction: (1) If the brushless motor is rotating forward, but the actual motor is reversed, the rotation direction of the motor must be adjusted. (2) If the working state of the brushless motor is forward rotation in a certain state and time, and reverse in another state and time, then the correct rotation of the motor must be controlled according to the working state and time of the brushless motor. motor. Generally, during the operation of a DC motor, changing the direction of the magnetic field or the polarity of the armature voltage can change the direction of the motor. The magnetic flux of a DC brushless motor is generated by permanent magnets, and its direction cannot be changed. In addition, due to the unidirectional conductivity of semiconductors, it is inconvenient to reverse the power supply voltage. Therefore, in this case, the rotation direction of the motor is generally changed by controlling the commutation sequence of the stator windings.

Brushless stepper motors use reducers in the following situations

(1) The stepper motor switches the frequency of the stator phase current, such as changing the input pulse of the stepper motor drive circuit to a low speed. When the low-speed stepper motor is waiting for the step command, the rotor is in a stopped state. When pedaling at a low speed, the speed fluctuates greatly. At this time, if you change to high-speed operation, the speed fluctuation problem can be solved, but the torque will be insufficient. That is, the torque will fluctuate at low speed, and the torque will be insufficient at high speed.

(2) The step angle of a small (50mm or less) PM type stepping motor is 7.5°. This kind of motor will have the problem of position control accuracy change.

(3) The output shaft of the stepper motor adopts a direct drive load mode. When the load crown beam is large, the acceleration torque will be insufficient.

(4) Where low-speed and high-torque braking is required.