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US 4,940,912 AGranted
Brushless electric motor with self starting asymmetry
AssigneesSociete de Ventilation et d'Electricite Appliquees Velecta, Gradient
InventorsMichel Kant, Jean-Marie Biedinger, Roland Quessard, Jacques Galko
Life of this patent
Estimating the term…
Abstract
The motor includes a rotor (2) with permanent magnets and a stator (3) that surrounds the rotor and includes reluctance pads (9, 10) provided to place the rotor (2), upon stopping, in a position where the startup of the motor will be assured. The reluctance pads (9, 10) are asymmetrical with respect to the magnetic axis (A) of the coils of the stator (3) and include notches (4), at least some of which serve to accommodate at least one coil of the stator (3), in order to assure obtaining a maximum winding coefficient.
Claims13
An electric motor with electronic commutation, including:
- a rotor (2) which includes permanent magnets (12, 13) disposed in such a manner as to define a magnetic rotor axis;
- and a stator (3) that surrounds the rotor and includes coils (5, 6, 7, 8) intended to be supplied with direct current, and defining a magnetic stator axis (A),
- commutation means (C) being provided for reversing the direction of the flow of current in the coils, so that the electromagnetic torque exerted by the stator (3) on the rotor (2) always acts in the same direction,
- means (D) sensitive to the position of the rotor being provided for controlling the commutation means (c) and for reversing the direction of flow of the current in the coils,
- reluctance pads (9, 10) being further provided in the stator (3) for placing the rotor (2) upon stopping in a position in which the startup of the motor will be assured, wherein
- said stator (3) includes an even number of notches (4) separated by teeth (11) spaced at regular intervals over the entire inside periphery of the stator (3),
- said reluctance pads (9, 10) are asymmetrical with respect to the magnetic stator axis (A) and are formed of two diametrically opposed groups of teeth and notches, the teeth not belonging to the reluctance pads having a length (1) less than the length (L) of the teeth belonging to the reluctance pads,
- said coils (5, 6, 7, 8) of the stator are accommodated in part (5, 6) in the notches of the reluctance pads (9, 10) and the remainder in the notches not belonging to the reluctance pads, such that said stator coils (5, 6, 7, 8) are placed in the vicinity of the diametral plane orthogonal to the magnetic axis (A) of the stator, so as to improve the winding coefficient, said axis of the reluctance pads being offset by 45.degree. with respect to the magnetic axis (A) of the coils of the stator, each reluctance pad having an angular length of approximately 100.degree..
5 more elements
An electric motor with electronic commutation, including:
- a rotor (2) which includes permanent magnets (12, 13) disposed in such a manner as to define a magnetic rotor axis;
- and a stator (3) that surrounds the rotor and includes coils (5, 6, 7, 8) intended to be supplied with direct current, and defining a magnetic stator axis (A),
- commutation means (C) being provided for reversing the direction of the flow of current in the coils, so that the electromagnetic torque exerted by the stator (3) on the rotor (2) always acts in the same direction,
- means (D) sensitive to the position of the rotor being provided for controlling the commutation means (c) and for reversing the direction of flow of the current in the coils,
- reluctance pads (9, 10) being further provided in the stator (3) for placing the rotor (2) upon stopping in a position in which the startup of the motor will be assured, wherein
- said stator (3) includes an even number of notches (4) separated by teeth (11) spaced at regular intervals over the entire inside periphery of the stator (3),
- said reluctance pads (9, 10) are asymmetrical with respect to the magnetic stator axis (A) and are formed of two diametrically opposed groups of teeth and notches, the teeth not belonging to the reluctance pads having a length (1) less than the length (L) of the teeth belonging to the reluctance pads,
- said coils (5, 6, 7, 8) of the stator are accommodated in part (5, 6) in the notches of the reluctance pads (9, 10) and for the remainder in the notches not belonging to the reluctance pads, such that said stator coils (5, 6, 7, 8) are placed in the vicinity of the diametral plane orthogonal to the magnetic axis (A) of the stator, so as to improve the winding coefficient, said axis of the reluctance pads being offset by 45.degree. with respect to the magnetic axis (A) of the coils of the stator, said stator including sixteen notches and sixteen teeth, the reluctance pads each including five teeth and four notches and being diametrically opposed, the six remaining teeth forming two groups also diametrically opposed and having a reduced length, two coils being accommodated in two notches of the reluctance pads located toward one angular end of these pads, while the other two coils of the stator are accommodated in the two immediately following notches.
5 more elements
Dependencies are inferred from the claim text.