| 摘要 |
In a brushless D.C. motor employing a permanent magnet rotor 1 and a two winding stator 2, 3 with electronic switching 4, 5 responsive to rotor position to improve efficiency, switching of the stator current is initiated in advance of the rotor reaching its neutral position so that the stator poles have more or less completed their change by the time the rotor reaches the neutral position. However, as, on starting, the rotor might therefore oscillate back and forth instead of rotating an override circuit 14 is included. When the rotor starts from a position between (in the desired direction of rotation) the point at which switching is initiated and the subsequent neutral axis 35, the override circuit 14 maintains the initial condition of the switching circuit for a predetermined period irrespective of the rotor sensor 35 output during that period. <IMAGE> |
