How does a DC motor achieve forward and reverse rotation?

The two power lines of the DC motor are not divided into positive and negative poles, assuming that the codes of the two power lines are A and B respectively. When the A line is connected to the positive pole and the B line is connected to the negative pole, the motor rotates forward (reverse); when the B line is connected to the positive pole and the A line is connected to the negative pole, the motor reverses (forward). (That is to say, as long as the positive and negative poles of the two power lines are exchanged, the forward and reverse of the DC motor can be realized). There are many ways to realize the positive and negative rotation of DC motors. Here are a few simple methods for you.

1. Keep the polarity of the terminal voltage of the excitation winding unchanged, and reverse it by changing the polarity of the terminal voltage of the armature winding of the DC motor;

2. Keep the polarity of the armature winding terminal voltage unchanged, and adjust the direction of the DC motor by changing the polarity of the excitation winding terminal voltage. When the polarity of both voltages changes at the same time, the direction of rotation does not change.

3. If it is controlled manually, a mechanical switch can be used to realize the positive and negative rotation of the motor, and a double-pole double-throw switch can be used, and the wiring is simple.

4. Use a two-way relay to realize the forward and reverse rotation of the DC motor. The principle is similar to method 3. The difference is that the relay is used as a switch, which can realize automatic programming control.

The reverse connection method of the excitation winding should be adopted for the series excited DC motor to realize forward and reverse rotation. The reason is that the voltage at both ends of the armature of the series excited DC motor is relatively high, while the voltage at both ends of the excitation winding is very low, and the reverse connection is easy. This method is often used in electric vehicles. 

The above is how Vshida Micromotor introduces to you how to achieve forward and reverse rotation of DC motors. For more information, please contact us.