BRAKE OPERATION SYSTEM OF INDUCTION MOTOR

摘要

PURPOSE:To realize a constant control of maximum brake current and a constant brake torque characteristic of an induction motor by changing a command voltage following variations in the frequency with a voltage-frequency converter with the application of the output of an excessive brake current detector inserted into a main circuit in the direction of increasing the command frequency. CONSTITUTION:In the brake operation of an induction motor 4, an actuating signal of an excessive brake current detector 7 inserted into a main circuit is applied to reduce a maximum current command from a maximum current setter 12 and a deviation signal overlaps a frequency command from a frequency command device 11 after amplified through a current adjustor 13 whereby the value for regulating the output frequency of an inverter 3 is increased according to an excessive brake current of the main circuit. The DC input voltage of the inverter 3 actuates a power converter 1 and a transistor 6 on the output side according to the frequency command varying through the voltage adjustor 16 to control the ratio of voltage to frequency to be constant.