Star Contactor Technical Introduction

During the operation of the elevator, the power failure causes the elevator to stop or the brake fails to stop the elevator due to some reasons. At this time, the elevator will lose the driving torque and the counterweight and the axle box will be out of balance, causing the elevator to slide. In severe cases, there will be a speeding Phenomenon. At this time, use the contactor used by the traction machine to seal the star, which is to short-circuit the three items of U, V, and W. So that the armature becomes three closed coils, at this time the elevator will drive the motor to rotate. As a result, the armature coil can realize the cutting of the permanent magnet during the rotation process to generate a magnetic field. A certain induced current is generated in the above closed coil, and the induced current will generate an induced voltage. This induced voltage is cut with the magnetic field to generate an opposite magnetic field. In this way, an upward moment for braking the elevator down is generated, and finally the elevator reaches a balance. The elevator can maintain a small speed and continue to move forward. It can be seen that the purpose of sealing the star of the traction machine is to play a certain braking role when the traction machine is in the state of no electricity and the elevator block and the speeding car at the same time. Fall, thereby inhibiting the speed of the elevator block and flying car. Once the torque is consistent with the motor torque, the traction machine can run at a constant speed. The contactor itself has two groups of main contacts, one of which is used to control the output of the frequency converter, and the other has a time delay to achieve star closure. That is to say, the contactor can ensure that the main contacts cannot be closed at the same time, and at the same time, it can ensure that after the normally closed electric shock is disconnected, the normally open electric shock will be delayed in connection. Similarly, there will be a delay and even close after the normally open is disconnected.