| 摘要 |
A magnetic position sensor has a stator ( 16', 36, 52 ) formed of magnetic material and a pair of magnets ( 14 a , 14 b ; 34 a , 34 b ; 54 a , 54 b ; 64 a , 64 b) rotatably mounted about the stator and movable between opposite angular extremities and spaced from the stator by a primary cylindrical air gap ( 5 ). A secondary air gap ( 4 ) is formed in a stationary member at a location at which the magnetic field varies with the angular position of the magnets. A first Hall Effect sensor ( 18 ) is disposed in the secondary air gap to measure the magnetic field there-across as an indication of the angular position of the magnets. A second reference sensor ( 22 ) is provided to detect the magnetic decay of the magnets. The second sensor can be a Hall Effect sensor disposed at a location at which the magnetic field is relatively constant, independent of the angular position of the magnets. The reference sensor output can be used as a diagnostic indicator or as a correction for the first sensor output.
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