Method of starting a motor
AssigneeNippon Densan Corporation
InventorIsao Kaneda
Life of this patent
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Abstract
A method of starting a motor comprising a first starting step of supplying an exciting current to armature coils, a first holding step for holding the exciting current after the first starting step, a second starting step of supplying an exciting current to the armature coils after the first holding step, a second holding step of holding this exciting current after the second starting step, and a third starting step of supplying an exciting current to the armature coils after the second holding step. In this method, the frequency f.sub.1 of the first holding step is larger than the characteristic frequency F.sub.0 of the rotation system of the motor (f.sub.1 >F.sub.0) and the frequency f.sub.2 of the second holding step is smaller than the characteristic frequency F.sub.0 of the rotation system (f.sub.2 <F.sub.0).
Claims21
A method of starting a motor equipped with a rotor having a permanent magnet and a stator having armature coils, which comprises
- a first starting step of supplying an exciting current to armature coils,
- a first holding step of holding the exciting current supplied to the armature coils for a first predetermined time (T.sub.1) after the first starting step,
- a second starting step of supplying the exciting current to the armature coils after the first holding step,
- a second holding step for holding the exciting current supplied to the armature coils for a second predetermined time (T.sub.2) after the second starting step, and
- a third starting step of supplying the exciting current to the armature coils after the second holding step,
- wherein the frequency f.sub.1 (1/2T.sub.1) of the first holding step is larger than the characteristic frequency F.sub.0 of the rotation system of the motor (f.sub.1 >F.sub.0) and the frequency f.sub.2 (1/2T.sub.2) of the second holding step is smaller than the characteristic frequency F.sub.0 of the rotation system of the motor (f.sub.2 <F.sub.0).
A method of starting a motor provided with a rotor having a permanent magnet and stator having armature coils, which comprises a first stepping step and a second stepping step for supplying a stepping current of a are determined pattern to the armature coils, and a rotation number detecting step provided between the first stepping step and the second stepping step, wherein when it is determined that the rotor is not rotating in the rotation number detecting step, the second stepping step is carried out, and on the other hand, when it is determined that the rotor is rotating in the rotation number detecting step, the second stepping step is omitted.
A method of starting a motor having a housing, a rotor rotatable relatively to the housing, a fluid dynamic pressure bearing interposed between the housing and the rotor, a permanent magnet mounted on the rotor and a stator equipped with armature coils, which comprises a preliminary stepping step for supplying a preliminary stepping current having a relatively high frequency to the armature coils and a stepping step for supplying a stepping current having a lower frequency than the frequency of the preliminary stepping current to be carried out after the preliminary stepping step, wherein slight vibrations are imparted to the rotor in the preliminary stepping step and the rotation of the rotor is substantially begun thereafter in the stepping step.
Dependencies are inferred from the claim text.