As we known, the Al-shell power resistors are used to brake for the inverter, so we can call them as braking resistors. To the system of high-inertance, the motor can produce current when reducing the speed. At the same time, the current can go to the inverter to rise the voltage of the inverter. When the rising voltage is to AC 700v-750v, the braking resistor is needed. The braking resistor can exchange the power to heat ,and release the heat. Especially, when the braking frequency is high, it has to release much power with heating, and the capacity of the resistor is larger.
In that condition, the braking resistors which are Al-shell resistors or waving-wire-wound resistors have to be good status of impacting and stability to protect the inverter and the peripheral componet.