The forward and reverse rotation of the motor means tha […]
The forward and reverse rotation of the motor means that the motor rotates clockwise and counterclockwise. The clockwise rotation of the motor is the forward rotation of the motor, and the counterclockwise rotation of the motor is the reverse rotation of the motor. According to the forward and reverse control circuit diagram and its principle analysis, in order to realize the forward and reverse rotation of the motor, as long as any two of the three-phase power supply lines connected to the motor are connected to each other, the purpose of reverse rotation can be achieved. The forward and reverse rotation of the motor is widely used, such as electric planers for driving, woodworking, bench drills, wire cutters, spin dryers, and lathes.
Motors need forward and reverse rotation in daily use. It can be said that the forward and reverse rotations of motors are widely used. For example, electric planers, bench drills, wire-cutting machines, spin dryers and lathes for driving and woodworking.
At first, people needed some kind of equipment to reverse and need to disassemble and replace the motor wires, but this method is cumbersome in actual use. Later, a smart person installed two knives to change the forward and reverse rotation of the motor by switching the knives. After a period of time, the reverse switch appeared. This kind of wiring is relatively simple and the volume is also reduced. Due to the limitation of contacts
With the birth of the contactor, the forward and reverse circuit of the motor has also been further developed. It can control the forward and reverse rotation of the motor more flexibly and conveniently, and add a protection circuit-interlock and double interlock in the circuit. Can realize low voltage and long-distance frequent control.
With the development of electronic technology, the positive and negative rotation of the motor has successively appeared PLC, single-chip microcomputer, etc., and further circuit improvements have also been made. In addition, some proximity switches and photoelectric switches have been added to the actual application circuit to realize two-way automatic control, which has laid the foundation for the development of industrial robots.
In order to enable the motor to rotate forward and reverse, two contactors KM1 and KM2 can be used to switch the phase sequence of the three-phase power supply of the motor, but the two contactors cannot be closed at the same time. If they are closed at the same time, it will cause a short circuit accident of the power supply. In order to prevent such accidents, reliable interlocking should be adopted in the circuit. Figure 1 is a control circuit that uses a button and a contactor to double interlock the motor in both forward and reverse directions.