Patent ID: 7868514
Filing Date: 2011-01-11
Classification: H01F,H02K

Abstract:
1. An electric motor, comprising a first rotor, a second rotor and a third rotor, a first permanent magnet, a second permanent magnet and a third permanent magnet, a first stator and a second stator, a first electromagnet and a second electromagnet, a shaft, a shaft rotation position sensor and an electric switch, the first rotor being mounted on the shaft, the second rotor being mounted on the shaft and separated from the first rotor by the first stator, the third rotor being mounted on the shaft and separated from the second rotor by the second stator, the first permanent magnet being located in the first rotor, the second permanent magnet being located in the second rotor, the third permanent magnet being located in the third rotor, the north south orientation of the first permanent magnet being the same as the north south orientation of the second and third permanent magnets, the north south axis of the first, second and third permanent magnets each being spaced radially from the longitudinal axis of the shaft, the north south axis of the first, second and third permanent magnets each being about parallel with the longitudinal axis of the shaft, the north south axis of the first and third permanent magnets being about coincident, the north south axis of the first permanent magnet being spaced rotationally from the north south axis of the second permanent magnet, the first electromagnet being located in the first stator so that when the first electromagnet is energized the north south axis of the first electromagnet is about parallel with the longitudinal axis of the shaft and spaced radially from the longitudinal axis of the shaft, the second electromagnet being located in the second stator so that when the second electromagnet is energized the north south axis of the second electromagnet is about parallel with the longitudinal axis of the shaft and spaced radially from the longitudinal axis of the shaft, the north south axis of the first and second electromagnets being about coincident and wherein one north south end of the core of each electromagnet is larger than the other north south end of the core of each electromagnet and wherein larger north south ends of each electromagnet are positioned to face each other, the shaft rotation position sensor being positioned to sense the rotation position of the shaft so that the first and second electromagnets can be energized by way the electric switch at a rotation position of the shaft when each of the first, second and third permanent magnets are near the first and second electromagnets to cause the shaft to rotate.