How to Reversely Connect a 3 Phase Motor?
Three-phase asynchronous motor is a kind of induction motor, which is powered by a 380V three-phase AC current at the same time. Because the rotor and stator rotating magnetic fields of the three-phase asynchronous motor rotate in the same direction, the rotational speed is different, and there is a slip rate, so it is called a three-phase asynchronous motor. The rotor speed of an ATO three-phase asynchronous motor is lower than the speed of the rotating magnetic field. The rotor windings move relative to the magnetic field to generate electromotive force and current and interact with the magnetic field to generate electromagnetic torque to realize energy conversion.
How does a 3-phase asynchronous motor realize forward and reverse rotation? Any exchange of any two phases can achieve reverse rotation. How to make the forward and reverse rotations do not happen at the same time. A good way is to interlock the forward and reverse control circuits.
1st, connect a forward and reverse circuit according to the circuit diagram in the video. The control circuit needs a 24VDC power supply.
2nd, we use safe voltage to control dangerous voltage and use a 24V ATO relay to control the coil of the 220V AC contactor. Two 220V AC contactors respectively control the forward and reverse rotation of the motor. The left is the main circuit, and the right is the control circuit. The main circuits L1, L2, L3 directly correspond to the motors U, V, W, and are controlled by KM1. KM2 controls reverse rotation and changes the phase sequence to W, V, U. Two relays KA1 and KA2 control KM1 and KM2 respectively. KA1 and KA2 are interlocked, which realizes the interlocking of the forward and reverse circuits.
Finally, Turn on the power switch. The button switch controls the forward and reverses the rotation of the motor respectively. We can test that when one of the buttons is pressed, the other button is invalid. It cannot affect the rotation state of the motor.
The following video is a detailed description of a 3-phase motor reverse connection.