| 摘要 |
A method and apparatus for supporting and translating a mass by magnetic attractive means. A ferromagnetic track may have repetitive magnetic discontinuities. A linear plural-phase ferromagnetic electric motor, which may be synchronous, supports the mass at a small gap below the track at zero frequency current variation through the motor. The same motor translates the mass along the track at a speed determined by the frequency of the plural-phase alternating current supplied to the motor. A nonlinear feedback circuit having plural sensor elements controls the magnitude of the alternating current supplied to the motor. This maintains the gap substantially constant despite varying loads and gradually corrects for unevenness of the track. The feedback circuit provides uniform stability and uniform dynamic response regardless of the length of the gap. |
