US 4,793,263 AGranted

Integrated linear synchronous unipolar motor with controlled permanent magnet bias

AssigneeThe Boeing Company

InventorsJohn J. Basic, Richard G. Gilliland

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Abstract

Disclosed is a single, integrated linear synchronous unipolar motor having high-energy permanent magnets operable along a substantially linear demagnetization curve and a polyphase coil. Collectively, the permanent magnets and polyphase coil provide for propulsion, suspension, braking and lateral control of a vehicle along a passive reaction rail. The permanent magnets provide the primary force for suspending the vehicle from the guideway, with a DC field control coil controlling the suspension gap between the vehicle and the reaction rail. The polyphase coil propels the vehicle along the track at a speed dependent upon the voltage and frequency of the supplied signal. The motor exhibits a high power factor and efficiency factor, resulting in a motor that can be operated from a power source having a lower KVA rating than that required for previous linear motor arrangements and that can be used in concert with a low-cost, passive guideway.

Claims20

Dependent claims

A single, integrated device for the magnetic suspension, propulsion, braking, and lateral control of at least one vehicle in cooperation with a passive guideway, said guideway having a passive reaction rail formed of a magnetic material and extending the length of said guideway, said device comprising:

a stator body affixed to said vehicle in confronting relationship with said reaction rail, said stator body being formed of magnetic material and including a plurality of teeth that are spaced apart from one another;
at least one high-energy permanent magnet operable along a substantially linear demagnetization curve and mounted to said stator body with the poles of each said permanent magnet arranged to produce a first magnetic field having lines of magnetic flux completing a path through each said permanent magnet, an adjoining portion of said stator body and said reaction rail, said first magnetic field producing an attractive force between said stator body and said reaction rail that tends to suspend said vehicle from said guideway;
means for maintaining a desired air gap between said guideway and said vehicle suspended from said guideway by said first magnetic field;
and,
a polyphase propulsion coil wound through the spaces between said teeth of said stator body, said polyphase propulsion coil for producing a wave of magnetic flux that continuously travels the length of said stator body when a polyphase, AC voltage is supplied to said propulsion coil, said wave of magnetic flux traveling at a speed directly proportional to the pole pitch and the frequency of said AC voltage and applying a force between said stator body and said reaction rail tending to cause said vehicle to be propelled along said guideway at said speed of said wave of magnetic flux.

2 more elements

A system for the magnetic suspension, propulsion, braking, and lateral control of at least one vehicle in cooperation with a passive guideway, said system comprising:

a passive reaction rail, formed of a magnetic material and extending the length of said guideway;
a stator body affixed to said vehicle in confronting relationship with said reaction rail, said stator body being formed of magnetic material and including a plurality of teeth that are spaced apart from one another;
at least one high-energy permanent magnet operable along a substantialy linear demagnetization curve and mounted to said stator body with the poles of each said permanent magnet arranged to prdouce a first magnetic field having lines of magnetic flux completing a path through each said permanent magnet, an adjoining portion of said stator body and said reaction rail, said first magnetic field producing an attractive force between said stator body and said reaction rail that tends to suspend said vehicle from said guideway;
means for maintaining a desired air gap between said guideway and said vehicle suspended from said guideway by said first magnetic field;
a polyphase, variable-voltage, variable-frequency, AC voltage source for producing a polyphase AC voltage;
and
a polyphase propulsion coil wound through the spaces between said teeth of said stator body, said polyphase propulsion coil for producing a wave of magnetic flux that continuously travels the length of said stator body when said polyphase, AC voltage produced by said AC voltage source is supplied to said propulsion coil, said wave of magnetic flux traveling at a speed directly proportional to the pole pitch and the frequency of said AC voltage and applying a force between said stator body and said reaction rail tending to cause said vehicle to be propelled along said guideway at said speed of said wave of magnetic flux.

4 more elements

Dependencies are inferred from the claim text.