Apparatus and method for starting a single-phase variable reluctance motor
First Claim
1. A single phase variable reluctance motor comprising:
- a stator, defining at least one stator pole;
at least one phase winding for energizing the stator pole;
a rotor, defining at least one rotor pole, the rotor being rotatable relative to the stator such that a magnetic circuit comprising the rotor and the stator is of cyclically variable inductance according to the position of the rotor pole with respect to the stator pole;
a magnet;
a member including ferromagnetic elements arranged to rotate with the rotor, both the magnet and the member being located outside the magnetic circuit, the magnet being positioned and the ferromagnetic element being arranged to prevent the rotor from coming to rest at a position of maximum or minimum inductance.
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Accused Products
Abstract
An apparatus and method for starting a single-phase variable reluctance motor defined by a stator having one or more pairs of projecting poles defining a principal axis and a rotor mounted on a rotatable shaft co-axial with the principal axis of the stator is provided. The apparatus includes a device for preventing the rotor from being halted in a position of zero-developed torque thereby enabling reliable starting of the motor. The device includes a vane defined by a ferromagnetic disk having alternating mark regions and space regions which is mounted to the rotatable shaft and may form part of a rotor position transducer. A permanent magnet is positioned so as to move the vane into a position at which starting torque of the desired direction will be developed when the motor is energized. A further embodiment combines the magnet with a Hall-effect sensor so that, in conjunction with the vane, a rotor position transducer is formed.
22 Citations
28 Claims
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1. A single phase variable reluctance motor comprising:
- a stator, defining at least one stator pole;
at least one phase winding for energizing the stator pole;
a rotor, defining at least one rotor pole, the rotor being rotatable relative to the stator such that a magnetic circuit comprising the rotor and the stator is of cyclically variable inductance according to the position of the rotor pole with respect to the stator pole;
a magnet;
a member including ferromagnetic elements arranged to rotate with the rotor, both the magnet and the member being located outside the magnetic circuit, the magnet being positioned and the ferromagnetic element being arranged to prevent the rotor from coming to rest at a position of maximum or minimum inductance. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
- a stator, defining at least one stator pole;
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10. A single-phase variable reluctance motor, comprising:
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a stator having at least one projecting pole that defines a principal stator axis; a rotor coupled to a rotatable shaft co-axial with the principal stator axis the rotor being rotatable relative to the stator such that a magnetic circuit comprising the rotor and the stator is of cyclically variable inductance according to the position of the rotor pole with respect to the stator pole; at least one energizing coil wound around the at least one stator pole forming a first winding; and means located outside the magnetic circuit for preventing the rotor from coming to rest in a position from which reliable restart of the motor cannot be insured. - View Dependent Claims (11, 12, 13, 14, 15, 16)
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17. A single-phase variable reluctance motor, comprising:
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a stator having at least one projecting pole that defines a principal stator axis; a rotor coupled to a rotatable shaft co-axial with the principal stator axis; at least one energizing coil wound around at least one stator pole forming a first winding; and a rotor position transducer which detects the position of the rotor relative to the stators the rotor position transducer including a rotating member coupled to the rotor and a magnetic sensor which interacts with the rotating member to prevent the rotor from coming to rest in a position from which energizing the at least one energizing coil will not start the rotor. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24)
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25. A method of starting a single-phase variable reluctance motor including a stator defining at least one stator pole;
- at least one phase winding for energizing the stator pole; and
a rotor defining at least one rotor pole, the rotor being rotatable relative to the stator such that a magnetic circuit comprising the rotor and the stator is of a cyclically variable inductance according to the position of the rotor pole with respect to the stator pole, said method comprising the step of applying a magnetic force to the rotor from a location outside of the magnetic circuit so as to prevent the rotor from coming to rest in a position of maximum or minimum inductance. - View Dependent Claims (26, 27, 28)
- at least one phase winding for energizing the stator pole; and
Specification