| 摘要 |
This disclosure describes an electronically commutated linear d.c. motor with an armature and field source fixed relative to each other and a third element on which motor action takes place, consisting of a salient pole structure into which magnetic flux is impressed with no physical contact and little or no reluctance change with axial motion. This machine retains all the virtues of conventional d.c. motors as efficient bilateral mechanical to electrical force transducers, with conventional or ironless armatures and permanent and electromagnet fields. It has a completely passive salient pole element which may be either the stationary or moving part of the motor. This disclosure also illustrates how the newly invented form of linear d.c. motor can be designed in such a way that the magnetic circuit is part of a suspension system. This dual functional use of the magnet and permeable iron minimizes weight and cost. The moving (relative to armature) element (part of the motor's field) is totally passive yet, acting like a multipole array of alternating polarity magnets is inexpensive for many applications. And, it provides a way of using a steel rails of any length as a track for vehicular levitation and propulsion. The efficiency and controllability of a D.C. traction motor can be superior to both types of A.C. motors currently being tested and marketed worldwide. The geometry of the magnetic circuit in the region of the suspension airgap is new and of special interest. The airgaps separating the parts in relative motion are magnetically in series but are so arranged that motion in the direction of suspension opens one as the other closes, reducing a source of control non-linearity.
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