| 摘要 |
PURPOSE:To eliminate the need for a frequency generator while simplifying structure and enable stable control for frequency by a method wherein speed signals in unison with the speed of revolution of a rotor are obtained from positional detecting signals. CONSTITUTION:Signals Sf from a reference oscillator 32 and signals Pv from a speed signal output device 19 are inputted to a frequency comparator 33, a constant- current drive circuit 35 is driven through an amplifier 34 in response to the comparing output, and the conduction conditions of motor coils 3-5 are controlled. The change of the speed of revolution of a rotor is transmitted to the speed signal output device 19 through a positional detector 9, and the speed of revolution of the rotor is controlled in a closed loop manner. |
