| 摘要 |
<p>A brushless motor wherein rotating magnetic fields are generated in armature windings in a synchronous driving mode, outputting successively n kinds of driving waveshapes or the ones of a first pattern to an n-th pattern and thereafter, outputting the driving waveshapes again from the first pattern successively and circularly. When changing over the synchronous driving mode into a rotor position sensing driving mode, commutation signals (7u-7z) are changed over from the synchronous signals to the signals based on rotor position sensing signals (6u-6w), at a time to output the n-th pattern after outputting the (n-1)-th pattern. Thereby, when changing over the synchronous driving mode into the rotor position sensing driving mode, the order of the commutation signals are connected adequately to each other without adding particular adjunctive circuits and the transition between the modes can be performed smoothly.</p> |
