Method for controlling a synchronous motor for implementation of an exact start/stop positioning operation in a recording apparatus

摘要

A method and apparatus for controlling a synchronous motor with an AC voltage. A rated value proportional to a desired frequency of the AC voltage and related to a rotational speed of the synchronous motor is provided. The rated value is continuously added up in an accumulator to provide added-up signal values. The added-up signal values are employed for addressing stored function values in a function value memory, the function values representing at least one AC voltage. The addressed function values are read out from the function value memory and are converted into at least one AC voltage having the frequency corresponding to the rated value. The AC voltage is supplied to the synchronous motor for generating a rotary field such that the frequency of the AC voltage defines the rotational speed of the synchronous motor.