MOTOR SPEED CONTROL USING A COUNTDOWN COUNTER

摘要

The speed of a hysterisis induction motor is controlled by eliminating selected pulses from the alternating current supply by loading a count-down register at regular intervals with a binary number, the register being connected to establish the current supply to the motor for so long as a number is present in the register. The pulses of the current so established are used to count down the register so that the supply is cut-off when the number reaches zero. The number determines the duration of the supply between successive loadings of the register and the speed is thus determined by the magnitude of the number.