| 摘要 |
PURPOSE:To detect step-out by providing a phase current control means for a pulse motor and two integrating circuits having different time constants and receiving voltage at a joint with each phase coil or current flowing therethrough and then comparing the outputs therefrom each other. CONSTITUTION:Integrators 7a, 7b are arranged at the next stages of rectifiers 6a, 6b whereas a voltage divider 8 is arranged at the prestage of one rectifier 6b and they function to suppress the output from the integrator 7b below the output from the integrator 7a even upon recovery to normal rotation. A comparator 9 compares the outputs from the integrators 7a, 7b each other. The voltage divider 8 and the rectifier 6a are provided with voltage at the joints of a transistor Qb and respective phase coils 31-34 as input signals. A step-out detector 5 detects step-out based on detection of abrupt droppage of the voltage at the joint. |
