WO2002001701A1

WO2002001701A1 - Electrical motor

Info

Publication number: WO2002001701A1
Application number: PCT/GB2001/002856
Authority: WO
Inventors: Alan Glyn Jones
Original assignee: Alan Glyn Jones
Priority date: 2000-06-27
Filing date: 2001-06-27
Publication date: 2002-01-03
Also published as: AU2001266187A1

Abstract

An electrical motor comprising a generally circular, substantially flat electrically conductive element (10) and a plurality of electromagnets (12) located in spaced apart relation around an edge of the electrically conductive member (10). The electromagnets comprise a generally U-shaped core consisting of two arms (14) of magnetically conductive material around which are wound coils (18) of electrically conductive material. The arms (14) of the electromagnets (12) are connected together at one end by an insulative connecting member or spacer (16). The coils of the electromagnets are all connected in series, and the electromagnets are energised by means of a phased or pulsed dc current/voltage supply, or an ac current/voltage supply. In use, when the electromagnets (12) are energised, the electrically conductive element (10) is suspended between the arms (14) of the electromagnets (12), an emf (and therefore a current) is induced in the electrically conductive element (10) which distorts the magnetic field produced by the electromagnets (12) and propels the electrically conductive element (10) to rotate.

Description

Electrical Motor

This invention relates to an electrical motor and, in particular, to an electrical motor which can be operated using either a direct current (dc) or an alternating current (ac) power supply for use in a wide range of applications, including automotive, industrial, nautical, aeronautical, and domestic.

Many different types of electrical motor, both ac and dc, are well known and widely used in various applications. Conventional electrical motors, particularly for providing rotational drive, have for many years revolved around the * induction' principle, whereby placing an electrical conductor in a changing magnetic field causes an electromotive force (emf) to be set up in the conductor which circulates a current, the effect of which is to distort the magnetic flux proximate to the conductor thereby causing a force to be exerted on the conductor which tends to drag or push it in the direction of the changing flux.

Such a known arrangement generally requires the provision of several coils, each of which is energised in parallel by a current such that a relatively high current input is required to obtain a high efficiency in operating speed. In other words, such conventional motors have a low 'turning power' -to-current size ratio and are therefore relatively inefficient in moving large weights. I have now devised an improved electrical motor which seeks to overcome at least some of the problems associated with conventional motors. Thus, in . accordance with a first aspect of the present invention there is provided an electrical motor comprising a generally circular, substantially flat electrically conductive element and a plurality of electromagnets located in spaced apart relation around an edge of said electrically conductive member, said electromagnets each comprising at least one coil of electrically conductive material, each of said coils being connected together in series.

The electromagnets will in most cases require a core of magnetically conductive material around at least a portion ■ of which the at least one coil is wound.

In accordance with a second aspect of the present invention, there is provided an electrical motor comprising a generally circular, substantially flat electrically conductive element and a plurality of electromagnets located in spaced apart relation around an edge of said electrically conductive member, at least some of the electromagnets comprising two coils of electrically conductive material, said edge of said electrically conductive member being positioned between said coils.

In a preferred embodiment, the electromagnets comprise a core comprising two arms of magnetically conductive material connected together at one end by a connecting member, a coil of conductive material being wound on each of said two arms, and the electrically conductive member being positioned between the arms of the cores.

The electromagnets of the electrical motor according to both aspects of the present invention may be energised by means of a dc, preferably square-wave, current/voltage supply, or an ac current/voltage supply.

In the second aspect of the present invention, the coils wound on the arms of the electromagnets are preferably connected together in series such that a relatively low current (and high voltage) is required to energise the electromagnet arrangement. Of course, the electromagnets of the first aspect of the present invention are preferably generally U-shaped as defined in accordance with the second aspect of the present invention. The electrically conductive member may be generally disc-shaped, in which case the electromagnets are located in spaced apart relation around the outer periphery of the disc-shaped member. However, the electrically conductive member may alternatively be generally annular, in which case the electromagnets can either be located around the outer periphery of the annular member, or they can be placed within the annular member around the edge of the member which defines the generally central opening.

The conductive member is preferably laminated, beneficially of steel and copper, and the laminations are preferably at an angle or tangent to the surface of the conductive member in order to maximise the "start up" torque. In one embodiment of the present invention, the electromagnets may comprise two, generally straight substantially parallel arms of magnetically conductive material connected together at one end thereof by an insulative connecting member which is substantially perpendicular to said arms. However, in a preferred embodiment, the at least the distal (or free) ends of the arms are beneficially curved towards each other, thereby maximising the magnetic field adjacent to the conductive member and allowing it to be suspended between the arms of the electromagnets and eliminating the need for bearings to prevent friction, although bearings may be provided to prevent contact between the conductive member and the electromagnets, when the motor comes to rest. In a most preferred embodiment, the electromagnets are arranged to produce an additional or increased electromagnetic field between the proximal (i.e. connected) ends of the electromagnets which acts on the edge of the conductive member in use. This may be achieved by providing an additional core element and coil on the connecting member, or the connecting member between the proximal ends of the arms may be relatively thin (so that the portions of the arms close to the proximal ends are relatively close together, with the arms extending outwardly at an angle from the connecting member to form a general V or C-shape. In this case, the distal ends are beneficially curved inwards towards each other.

In another embodiment, the additional core member provided on the connecting member may carry a 'reverse direction' conductive coil capable of conducting an induced electrical current which can be used to regulate the speed of rotation of the motor and/or to recharge a battery used to provide the current to energise the electromagnets.

The conductive member may comprise or be attached to the hub of a wheel of a vehicle, such that the electrical motor can be used to drive a vehicle. Alternatively, the conductive member may be rigidly connected to the end of a shaft of, for example a boat or aeroplane propellor.

The electrical motor of the invention relies on a high voltage rather than a high current (because the coils of the electromagnets are connected in series) , thus enabling a smaller battery to be used than for conventional motors. This increases the 'turning power' -to-size ratio, enabling it to be used for propulsion of wheeled vehicles, boats or aeroplanes, for example. In summary, the electrical motor of the present invention is considered to offer a high efficiency-to-battery size alternative to conventional electrical motors.

Exemplary embodiments of the invention will now be described with reference to the accompanying drawings, in which:

Figure 1 is a schematic view of an electrical motor according to a first embodiment of the present invention; Figure 2 is a side view of the electrical motor of Figure 1;

Figure 3 is a side view of an electrical motor according to a second embodiment of the present invention;

Figure 4 is a side view of an electrical motor according to a third embodiment of the present invention;

Figure 5 is a perspective view of an electrical motor according to an exemplary embodiment of the present invention, when in use;

Figure 6 is a schematic view of an electrical motor according to a fourth embodiment of the present invention;

Figure 7 is a side view of the electrical motor of Figure

Figure 8 is a side view of an electrical motor according to a fifth embodiment of the present invention;

Figure 9 is a side view of an electrical motor according to a sixth embodiment of the present invention; ahd

Figure 10 is a perspective view of an electrical motor according to another exemplary embodiment of the present invention.

Referring to Figures 1 and 2 of the drawings, an electrical motor according to a first embodiment of the present invention comprises a generally disc-shaped member 10 of electrically conductive material. The disc-shaped member 10 is of laminated steel and copper, with the laminations at an angle or tangent to the surface of the disc-shaped member 10 in order to maximise the "start up" torque.

Electromagnets 12 are located around the peripheral edge of the disc-shaped member 10, each being a substantially equal distance apart. In the embodiment shown, four electromagnets 12 are provided. However, in a typical embodiment, at least eight electromagnets are preferred. The electromagnets each comprise two substantially straight, substantially parallel arms 14 of magnetically conductive material such as soft iron or mild steel. The arms 14 are connected together at one end by an insulative connecting member 16, perpendicular to the arms 14, to form a generally U-shaped element, the edge of the disc-shaped member 10 being located between the two arms 14. Around each of the arms 14 is wound a coil 18 of electrically conductive wire, such as copper or aluminium wire and the coils 18 are all joined together in series.

When the coils 18 are energised by a pulsed direct current or alternating current flowing through each of the coils in series, a magnetic field is produced between the two arms 14 which acts on the disc-shaped member 10 enabling it to be- suspended between the arms of the electromagnets 12, and causes an emf (and therefore a current) to be set up in the disc-shaped member 10, causing a distortion of the magnetic flux and resulting in 'free' rotational movement of the disc-shaped member 10, the direction of rotation being dependent upon the direction of flow of the current through the coils. The coils 18 may be energised by means of a square-wave dc current or an ac current, controlled by a microprocessor.

The variables which affect both operating efficiency and application are: frequency of the (square-wave) direct current, the magnitude of the voltage across the electromagnets, the dimensions of the electrically conductive member, the materials used in the electrically conductive member, the phasing or pulsing of the (square- wave) direct current, and the proximity of the electromagnets to each other.

Referring to Figure 3 of the drawings, in a second embodiment of. the invention, the distal ends of arms 14 of the electromagnets 12 may curve inwardly towards each other, to increase the strength of the magnetic field adjacent the disc-shaped member 10. Referring to Figure 4 of the drawings, in a third embodiment of the present invention, the connecting member 16 may be provided with an additional 'reverse direction' coil 20 in which a current may be induced due to the movement of the electrically conductive member through a magnetic field. This induced current may be used to recharge the battery supplying the electrical motor or for controlling (i.e. increasing or decreasing) the speed of rotation of the electrically conductive member 10, for example. Referring to Figure 5 of the drawings, one exemplary embodiment of the electrical motor of the invention comprises a ring-shaped, insulative spacer or connecting member 16 surrounding a generally disc-shaped electrically conductive member 10. The arms 14 of the electromagnets 12 are connected to the spacer 16 approximately 45 degrees apart, so that the disc-shaped member 10 is positioned between the coils 18. The disc-shaped member is provided with a central recess 22 which receives and retains the end of a shaft 24 of, for example, a propellor so that rotation of the electrically conductive member results in corresponding rotation of the shaft 24.

Referring now to Figures 6 and 7 of the drawings, the embodiment of the invention shown is similar in many respects to that described with reference to Figures 1 and 2, and the same reference numerals are used to denote the corresponding elements. However, in this case, the electrically conductive member 10 is generally annular having a relatively large, substantially central opening

26. The electromagnets 12, in this case, are positioned at substantially 45 degrees apart around the inner edge of the annular member 10 which defines the central opening 26, as shown .

Figure 8 shows a similar arrangement to that of Figure 7, except that the distal ends of the electromagnets 12 are curved inwardly towards each other, as described with reference to Figure 3. Similarly, Figure 9 of the drawings shows a similar arrangement to that of Figure 8, except that an additional 'reverse direction' coil 20 is provided on the connecting member 16 between the proximal ends of the arms 14 of the electromagnets 12, as described with reference to Figure 4 of the drawings.

Referring to Figure 10 of the drawings, an exemplary embodiment of 'an electrical motor according to the invention comprises a ring-shaped, insulative spacer or connecting member 16 located within the central opening 26 of ^' the annular electrically conductive member 10. As before, the arms 14 of the electromagnets 12 are connected to the spacer 16 approximately 45 degrees apart such that the annular member 10 is positioned between the arms 14, as shown .

Embodiments of the present invention have been described above by way of example only, and it will be apparent to persons skilled in the art that modifications and variations can be made without departing from the scope of the invention as defined by the appended claims.

Claims

CLAIMS :

1. An electrical motor comprising a generally circular,, substantially flat electrically conductive element and a plurality of electromagnets located in spaced apart relation around an edge of said electrically conductive member, said electromagnets each comprising at least one coil of electrically conductive material, each of said coils being connected together in series.

2. An electrical motor according to claim 1, wherein said electromagnets each comprise a core -of magnetically conductive material around at least a portion of which the at least one coil is wound.

3. An electrical motor comprising a generally circular, substantially flat electrically conductive element and a plurality of electromagnets located in spaced apart relation around an edge of said electrically conductive member, at least some of the electromagnets comprising two coils of electrically conductive material, said edge of said electrically conductive member being positioned between said coils.

4. An electrical motor according to any one of claims 1 to 3, wherein the electromagnets each comprise a core, comprising two arms of magnetically conductive material connected together at one end by a connecting member, a coil of conductive material being wound on each of said two arms, and the electrically conductive member being positioned between the arms of the cores.

5. An electrical motor according to any one of the preceding claims, wherein the electromagnets are energised by means of a dc pulsed or phased (preferably square-waved) current/voltage supply, or an ac current/voltage supply.

6. An electrical motor according to any one of claims 1 to 5, wherein said electrically conductive member is generally disc-shaped, and the electromagnets are located in spaced apart relation around the outer periphery of the disc-shaped member.

7. An electrical motor according to any one of claims 1 to 5, wherein said electrically conductive member is generally annular, and wherein the electromagnets are located around the outer periphery of the annular member, or located within the annular member around the edge of the member which defines a generally central opening.

8. An electrical motor according to any one of the preceding claims, wherein said electrically conductive member is laminated.

9.• An electrical motor according to claim 8, wherein the laminations of the electrically conductive member are at an angle or tangent to the surface of the electrically conductive member.

10. An electrical motor according to any one of the preceding claims, wherein the electromagnets comprise two, generally straight substantially parallel arms of magnetically conductive material connected together at one end thereof by an insulative connecting member which is substantially perpendicular to the arms.

11. An electrical motor according to any one of claims 1 to 9, wherein the electromagnets comprise two arms of magnetically conductive material connected together at one end thereof by an insulative connecting member, the distal (or free) ends of the arms being curved towards each other.

12. An electrical motor according to claim 10 or claim 11, wherein an induction coil is provided on said connecting member in which a current is induced, in use, when said electrically conductive member moves through a magnetic field produced by said electromagnets .