Motor speed control apparatus

摘要

A motor speed control apparatus (e.g. for a sewing machine) comprises: at least one setter 1 for setting a speed instruction voltage to give a speed instruction signal to the motor; an A/D converter 2 for converting the speed instruction voltage into a digital quantity; first storage means 4 storing reference voltage(s) of predetermined reference voltage region(s); second storage means 5 storing speed setpoint value(s) corresponding to said reference voltage region(s); and a central processing unit which compares the speed instruction voltage input via the A/D converter with said reference voltage(s), determines within which reference voltage region of the first storage means said speed instruction voltage lies and reads a corresponding speed setpoint value from the second storage means 5 and sends it as a speed instruction signal. ……