The customized induction motor should understand that there are three braking modes: energy consumption braking, reverse braking and regenerative braking.
(1) During energy consumption braking, cut off the three-phase AC power supply of the motor and send the direct current into the stator winding.At the moment of cutting off ac power, due to inertia, the motor still rotates in the original direction. This mode is characterized by stable braking, but requires DC power supply and high-power motor, which requires high cost of DC equipment and low braking force at low speed.
(2) Reverse connection brake can be divided into load reverse connection brake and power reverse connection brake.
1) Load reverse connection brake is also called load reverse connection brake.This torque causes the weight to descend slowly and steadily.The characteristics of this kind of braking are: the power supply does not need reverse connection, no special braking equipment is needed, and the braking speed can be adjusted, but it is only suitable for the winding motor, whose rotor circuit needs to be connected with a large resistance, so that the slip ratio is greater than 1.
2) Reverse connection braking When the motor needs to brake, as long as the two-phase power line is randomly adjusted, the rotating magnetic field can be reversed quickly.When the motor speed is equal to zero, immediately cut off the power supply.This kind of brake characteristic is: stop fast, brake power is stronger, need not brake equipment.But braking due to the current is large, the impact force is also large, easy to make the motor overheating, or damage the transmission parts.
(3) Regenerative braking, also known as feedback braking, under the action of heavy loads (when the crane motor lower the heavy loads), the motor speed is higher than the synchronous speed of the rotating magnetic field.At this time, the rotor conductor induced current, under the action of the rotating magnetic field to produce anti-rotation direction torque, but the motor speed is high, need to slow down the speed change device.
