US 6,037,692 AGranted

High power low RPM D.C. motor

OwnerFred N. Miekka, Peter W. Mackieinventors

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Abstract

A high power low RPM direct current electric motor is disclosed whereby the high power output is achieved in one of two ways or both. In the first case, the need for cooling is reduced simultaneously along with an increase in the utilization of the magnetic field present in the motor permanent magnets. This is achieved by wrapping the electromagnet core with windings that are capable of demagnetizing the rotor permanent magnets under stall conditions. Interlocking motor circuitry is provided which prevents the full activation of these motor windings until motor RPM values reach a safe level. This increases motor power while decreasing resistive losses in electromagnet windings. In the second case, the rotary portion consists of a large diameter relatively flat rotor containing permanent magnets and having built in vanes for moving air over the electromagnet stator windings providing forced air cooling.

Claims11

Dependent claims

A brush timed permanent magnet electric motor, comprising:

a stationary portion including:
a housing having an inner surface and end caps;
and
a plurality of permanent magnets each being disposed on said inner surface of said housing and having a direction of magnetization and poles;
said poles of said permanent magnets facing inward in a radial direction and alternating with each successive of said permanent magnets;
a rotatable portion including:
a shaft rotatably attached to said end caps of said housing;
and
a plurality of electromagnets each being attached to said shaft, having a direction of magnetization and poles, and including a winding capable of conductive current;
said poles of said electromagnets facing outward in said radial direction and alternating with each successive of said electromagnets;
and
said winding of at least one of said electromagnets having a configuration that demagnetizes said permanent magnets at stall conditions;
an electrical interlocking circuitry for allowing said configuration of said winding of said at least one of said electromagnets to be activated when said shaft reaches a preset speed that reduces current in said windings to a level sufficient to prevent demagnetization of said permanent magnets;
a commutator attached to said shaft;
and
a set of brushes attached to said housing for applying electric power to said electromagnets to cause said shaft to rotate.

13 more elements

Dependencies are inferred from the claim text.

Facts

Application: 09/088,096Filed 1 Jun 1998 · continuation in part
Priority: 16 Dec 1997
Granted: 14 Mar 2000
Term ends: Not estimatedThe source records don’t support an estimate.

Classification26 codes

H02K 19/103
For multi-phase current: motors having windings on the stator and a variable reluctance soft-iron rotor without windings
B60L 50/60
Using propulsion power supplied by batteries or fuel cells: using power supplied by batteries
H02K 1/08
Characterised by the shape, form or construction: salient poles
H02K 1/2795
Rotors axially facing stators: the rotor consisting of two or more circumferentially positioned magnets