| 摘要 |
An electric step motor has a sensor which functions to sense the position of the rotor. The sensor has an output which is connected to a first input of a unit for measuring lead angle. The measuring unit has an output which is coupled to a first input of a comparator having a second input which is connected to a selector for choosing a desired lead angle. The comparator is connected to an input of, and functions to regulate, a pulse generator which is set to emit pulses at a constant frequency equal to the rated operating frequency of the motor. The pulse generator has an output which is connected to a drive circuit for the motor, and such output is further connected to a second input of the measuring unit. The measuring unit informs the comparator of the actual lead angle. The comparator compares the actual lead angle with the desired lead angle established by the selector and activates the pulse generator accordingly. The pulse generator thereupon emits a specified number of pulses at the rated operating frequency of the rotor thereby causing the rotor to move. The comparator deactivates the pulse generator when no further displacement of the rotor is required.
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