PREVENTING METHOD FOR BURNING OF LINEAR MOTOR COIL

摘要

PURPOSE:To prevent the burning of a linear motor coil by having the output of a command for shift distance of small numerical value in case the shift of the coil is impossible up to a target position due to an external factor and obtaining a positioning end signal to eliminate the overload of the linear motor. CONSTITUTION:In case no positioning end signal is received within a fixed time after the output of a digital shift distance command received from a control microcomputer 2 in the first step, an operator call signal is produced in the next step and an error message is displayed on a screen. Then a digital shift distance command of small numerical value is outputted in the direction opposite to that of the digital shift distance command received from the microcomputer 2. In this case, the former command signal is continuously outputted until the positioning end signal is given to the microcomputer 2 from a window comparator 9. As a result, no overload is applied to a linear motor and therefore no energizing current flows continuously to a coil for a long period of time.