US 5,258,697 AGranted

Efficient permanent magnet electric motor

AssigneeVarelux Motor Corp.

InventorsJames R. Ford, William H. Johnson, W. DeWitt Lyon

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Abstract

An electric motor, of the type that includes a rotor with permanent magnets and a stator with electromagnets, which operates at high efficiency to produce a high ratio of mechanical power output to electrical power input. During rotor rotation in a first direction (74, FIG. 5), a first magnet (44A') moves away from a position of alignment with the core of a "last" electromagnet (46A), while a second permanent magnet (44B') moves toward a position of alignment with the core of a "next" electromagnet (46C) which it is approaching. The last electromagnet (46A) is energized in a direction to negate attraction of its core (50) for the first permanent magnet (44A'). The next electromagnet (46C) is not substantially energized, so the attraction of the second magnet for the next electromagnet (46C) is due primarily to attraction of their cores in the absence of energization of the next electromagnet. Thus, most electrical power supplied to the electromagnets are to negate attraction between a permanent magnet and the last electromagnet which the permanent magnet is moving away from. This allows most motor output torque to arise from the attraction of permanent magnets for the cores of unenergized electromagnets that the permanent magnets are approaching.

Claims9

Dependent claims

An electric motor comprising:

a rotor having an axis of rotation and having a plurality of permanent magnets spaced about said axis;
a stator having a plurality of electromagnets spaced about said rotor axis, each of said electromagnets having a core of magnetic material and a coil, said electromagnetics being spaced relative to said permanent magnets, so as said rotor rotates in a first direction, then during a predetermined angle of rotor movement a first of said permanent magnets moves away from a recently attained center alignment position with a last of said electromagnets and a second of said permanent magnets moves toward a soon-to-be-attained alignment position with a next of said electromagnets;
a control circuit coupled to said electromagnets to energize them, said circuit being constructed so during motor operation at moderate loads, said circuit does not substantially energize said next electromagnet as said second magnet moves toward said alignment position therewith so most attractive force between said second magnet and next electromagnet arises from the attraction of said second magnet toward said magnetic core of said next electromagnet, and said circuit energizes said last electromagnet primarily to negate the backward attraction of said first magnet for said magnetic core of said last electromagnet, so that more of the torque arising from interactions of said last and next electromagnets with said first and second magnets tending to rotate said rotor in said first direction, arises from the attraction of said second magnet toward said core of said next electromagnet in its unenergized state than any repulsion of said first magnet from said last electromagnet plus any attraction of said second magnet for said next electromagnet arising from energizing of said next electromagnet.

Dependencies are inferred from the claim text.

Facts

Application: 07/780,968Filed 23 Oct 1991
Granted: 2 Nov 1993
Term ends: Not estimatedThe source records don’t support an estimate.

Classification12 codes

H02K 21/20
With magnets rotating within the armatures: having windings each turn of which co-operates only with poles of one polarity, e.g. homopolar machine
B60L 50/60
Using propulsion power supplied by batteries or fuel cells: using power supplied by batteries
H02K 21/22
With stationary armatures and rotating magnets: with magnets rotating around the armatures, e.g. flywheel magnetos
H02K 29/10
With position sensing devices: using light effect devices