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Why use the inverter braking resistor?
Feb 08, 2018

Why use the inverter braking resistor?


    Braking resistor, a kind of stainless steel resistor, is mainly used in the mechanical system of the inverter to control the fast parking of the motor to help the motor convert the regenerative electric energy generated by the quick parking into heat energy. 1, the protection of the inverter from renewable energy hazards. 2, to ensure the smooth operation of the power supply network. In the frequency control system, the motor speed down and stop by gradually reducing the frequency to achieve, in the moment the frequency decreases, the synchronous motor speed decreases, and due to mechanical inertia, the motor rotor speed is not change. When the synchronous speed is less than the rotor speed, the phase of the rotor current is almost changed by 180 degrees, and the motor changes from the electric state to the power generation state. At the same time, the torque on the motor shaft becomes the braking torque, Decrease, the motor is in regenerative braking. Motor regeneration of the energy by freewheeling diode full-wave rectifier feedback to the DC circuit. Since the DC power can not be fed back to the power grid through the rectifier bridge, it is absorbed by the inverter itself. Although the other part can consume power, the capacitor still has a short time of charge accumulation, forming a pump-up voltage and increasing the DC voltage. Excessive DC voltage will damage all parts of the device. So in the mechanical inertia bigger system, needs to use the brake resistance, like the elevator, the numerical control engine bed, hoists and so on.