| 摘要 |
PURPOSE:To realize a quiet motor by reducing noise vibration generated at the time of operating a brushless DC motor. CONSTITUTION:1) Noise of a motor is previously measured, a current waveform in which noise of a frequency synchronized with a rotation is reduced, is obtained, the waveform is stored in a PROM 600, this information is called at the time of operating, a current corresponding to a load is applied to driving coils 51, 52 53 thereby to reduce the noise. 2) Noise measuring means made of a microphone 620, etc., is provided in an apparatus, noise at the time of operating is measured, and a current waveform is always so set that the noise of the frequency synchronized with the rotation becomes a predetermined value or less. 3) Noise measuring means made of a microphone 622, etc., is provided in an apparatus, noise of an initial state of an operation is measured, and a current waveform is so set that the noise of the frequency synchronized with the rotation at that time becomes a predetermined value or less. This information is stored in a RAM 605, and then it is operated with the waveform as a reference. |
