DC motor forward and reverse control circuit

DC motor forward and reverse control circuit

In practical applications, the reversing circuit of a DC motor
    requires that some DC motors must be able to rotate both forward and reverse, such as the DC motors used in audio recorders and video recorders
. Changing the direction of the current in the armature winding , or changing the direction of the stator magnetic field, can change the direction of the motor. But for permanent
magnet DC motors, the purpose of changing the direction of the motor can only be achieved by changing the direction of the current.
    The figure shows the forward and reverse control circuit of a DC motor . In the figure, Rt and Rz are adjustable resistors. Changing the resistance value of Rl can change the current of the excitation winding, thereby adjusting the strength of the magnetic field; and changing R2 The resistance value can change the speed of the motor. The double-pole double-throw switch S in the figure is a control switch used to change the rotation direction of the motor. When the switch S is turned to the "l'' position, the current flows in from the a brush and flows out from the b brush. When the switch S is turned to the "2" position, the current flows in from the b brush and flows out from the a brush. . It can be seen that changing the state of switch S can change the current direction of the armature winding, thereby achieving the purpose of changing the direction of the motor. . As long as a switch is connected between the power supply and the motor, the start and stop of the motor can be controlled , which constitutes a simple motor drive circuit. If you want to shorten the stop time, you can use energy consumption braking when stopping. It just adds a path . The resistor is to limit the generated current so that it does not exceed Large. However, these circuits cannot change the direction of current flowing into the motor , and the motor cannot rotate in the opposite direction.