WO2016141425A1

WO2016141425A1 - Electric machine

Info

Publication number: WO2016141425A1
Application number: PCT/AU2016/050155
Authority: WO
Inventors: Darren Powell
Original assignee: Coaxe Engine Company Pty Ltd
Priority date: 2015-03-06
Filing date: 2016-03-05
Publication date: 2016-09-15

Abstract

The present invention provides a combination engine and electricity generator. The generator portion comprises an armature component and a magnetic field component, the armature and magnetic components being movable relative to each other so as to generate electrical power, wherein the electric machine is configured such that component is movable relative to the second component, and the second component is movable relative to the first component, wherein the first and second components are movable along a line and in different directions. The movement of the components along a line in different directions is provided by an internal combustion engine capable of providing contra-rotational output.

Description

ELECTRIC MACHINE

FIELD OF THE INVENTION

The present invention relates to apparatus and methods for the generation of electricity by mechanical means. More particularly, but not exclusively, the invention includes improved electricity generators driven by mechanical engines.

BACKGROUND TO THE INVENTION

Mechanically driven generators are well known contrivances that convert kinetic energy into electrical energy. The source of kinetic energy used to drive a generator varies widely and includes means such as a hand crank, a wind-driven propeller, a gas fired turbine, or an internal combustion engine.

Where an electricity generator is coupled to an engine, the arrangement is commonly referred to as a "genset". A genset may be used to supply electrical power in remote areas, or for backup power generation as a component of an uninterruptible power supply. The engine used in a genset is often an internal combustion engine.

Electromagnetic electricity generators fall into one of two broad categories: dynamos and alternators. Dynamos generate direct current, usually with voltage and/or current fluctuations, usually through the use of a commutator. Alternators generate alternating current, which may be rectified by an additional system.

Electromagnetic electricity generators have two basic mechanical components: the rotor (being a rotating component), and the stator (being a stationary component). Generators also include two basic electrical components: the armature (being the power-producing component which can be on either the rotor or the stator), and the magnetic field component (typically provided by either electromagnets or permanent magnets mounted on either the rotor or the stator. More typically, the armature forms part of the rotor and rotates within a magnetic field established by magnets forming part of the stator.

A problem in the art relates to the efficiency of conversion of kinetic energy into electrical energy. For example, where an engine is used to supply rotational mechanical power to a generator there are considerable efficiency losses due to frictional losses, heat losses and the like. A further problem in the art is that high rotational speeds are required to turn generators. There is some difficulty in providing the required rotational speed high speed and at a minimum torque to rotate the generator rotor. Engines of relatively large capacity must be used to obtain the required torque and rotational speeds, this adding to the complexity and cost of power generation.

Yet a further problem in the art relates to need to effectively dissipate heat from a generator. Efficiencies in electrical generation may decrease where temperature increases over a threshold. Prior art generators address cooling issues by the use water jackets, heat fins, heat sinks and the like all of which add cost and complexity.

It is an aspect of the present invention to overcome a problem in the art by providing improved or alternative apparatus for the production of electrical power. The discussion of documents, acts, materials, devices, articles and the like is included in this specification solely for the purpose of providing a context for the present invention. It is not suggested or represented that any or all of these matters formed part of the prior art base or were common general knowledge in the field relevant to the present invention as it existed before the priority date of each claim of this application.

SUMMARY OF THE INVENTION

In a first aspect, but not necessarily the broadest aspect, the present invention provides an electric machine comprising an armature component and a magnetic field component, the armature and magnetic components being movable relative to each other so as to generate electrical power, wherein the electric machine is configured such that component is movable relative to the second component, and the second component is movable relative to the first component, wherein the first and second components are movable along a line and in different directions.

In one embodiment, the electric machine is configured such that the first and second components are moveable along a common line and in substantially opposite directions. In one embodiment of the electric machine, the first and second components rotate about a common axis. In one embodiment of the electric machine, the first component rotates within the confines of the second component.

In one embodiment of the electric machine, the first and/or second components are configured to connect to a source of mechanical rotational power.

In one embodiment of the electric machine, the first and second components are configured to connect to a single source of mechanical rotational power. In one embodiment of the electric machine, the source of mechanical rotation is an engine.

In a second aspect, the present invention provides an electric machine-engine combination comprising the electric machine as described herein, and at least one engine, the electric machine and engine(s) being mechanically coupled such that the first and second components are moved relative to each other.

One embodiment the electric machine-engine combination consists of a single engine, the single engine and electric machine being mechanically coupled such that the single engine moves the first and second components.

In one embodiment the electric machine-engine combination the engine is an internal combustion engine.

In one embodiment the electric machine-engine combination the engine is capable of providing contra-rotational output. The first rotational direction of the contra-rotational output may be mechanically coupled to the first electric machine component, and the second rotational direction of the contra-rotational output may be mechanically coupled to the second electric machine component. In a third aspect, the present invention provides a method of generating electrical power, the method comprising providing an armature component and a magnetic field component, moving the first component relative to the second component, and moving the second component relative to the first component so as to generate electrical power, wherein the first and second components are moved alone a line and in different directions.

In one embodiment, the method comprises use of the electric machine as described herein. In one embodiment, the method comprises comprising use of the electric machine-engine combination as described herein.

In one embodiment of the method, where the engine of the electric machine-engine combination is capable of providing contra-rotational output, the method provides a fuel saving for each unit of electrical power generated compared with a substantially identical electric machine-engine combination configured such that only the first electric machine component moves relative to the second electric machine component, or the second electric machine component moves relative to the first.

In one embodiment of the method, the fuel saving is at least about 1 %, or at least about 2%, or at least about 3%, or at least about 4%, or at least about 5%.

In one embodiment of the method the fuel saving is at least about 10%, or at least about 15%, or at least about 20%, or at least about 25%.

In another aspect, the present invention provides electrical power in usable or vendible form produced by the method as described herein. In a further aspect the present invention provides a method of providing mechanical contra- rotational output, the method comprising the steps of providing the electric machine as described herein, applying an electric current two the armature component under conditions such that the armature component and magnetic field component contra-rotate relative to each other.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a cross-sectional diagram of a preferred electricity generation system of the present invention comprising a reciprocating coaxial crankless engine providing contra-rotational outputs, the outputs coupled to a generator.

Fig. 2 is a diagram of an end-face of the generator housing showing in Fig. 1 . DETAILED DESCRIPTION OF THE INVENTION

After considering this description it will be apparent to one skilled in the art how the invention is implemented in various alternative embodiments and alternative applications. However, although various embodiments of the present invention will be described herein, it is understood that these embodiments are presented by way of example only, and not limitation. As such, this description of various alternative embodiments should not be construed to limit the scope or breadth of the present invention. Furthermore, statements of advantages or other aspects apply to specific exemplary embodiments, and not necessarily to all embodiments covered by the claims.

Throughout the description and the claims of this specification the word "comprise" and variations of the word, such as "comprising" and "comprises" is not intended to exclude other additives, components, integers or steps.

Reference throughout this specification to "one embodiment" or "an embodiment" means that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, appearances of the phrases "in one embodiment" or "in an embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment, but may.

The present invention is predicated at least in part on Applicant's finding that improvement in efficiencies in power generation or other advantages may be obtained where the stator of a generator is moved relative to the rotor, this movement being additional to movement of the rotor relative to the stator. Accordingly, in a first aspect the present invention provides an electric machine comprising an armature component and a magnetic field component, the armature and magnetic components being movable relative to each other so as to generate electrical power, wherein the electric machine is configured such that component is movable relative to the second component, and the second component is movable relative to the first component, wherein the first and second components are movable along a line and in different directions. .

As used herein, the term "electric machine" is intended to mean any electromagnetic contrivance capable of generating electrical power, including alternating current or direct current. The present electric machines may be described by reference to terminology of prior art generators. Thus, the first component may be a rotor comprising an armature, and the second component a stator comprising a magnet. However given that according to the present invention both components are rotatable relative to each other, the stator (and associated magnet) is not stationary but is rotatable in the opposite direction to the rotational direction of the rotor. It will therefore be understood that a prior art stator may be modified so as to be movable relative to the rotor in order to function as an electric machine of the present invention.

Prior art generators fix the stator in a set position typically by way of a housing or frame. The present invention is a significant departure from that accepted dogma, with the use of a movable stator component providing practical advantage as more fully described infra.

As will be readily apparent to the skilled person, the armature component of a generator is typically a component of a rotor, and the magnetic field component typically a component of the stator. While such an arrangement is typical in an electricity generator, the present electric machines do not necessarily require components that could be defined strictly as a stator and/or rotor.

According to the present invention, there is an increased relative velocity of the armature component to the magnetic field component (and also the velocity of the magnetic field component to the armature component). This increased relative velocity is achieved without increasing the absolute velocity of the armature component. Considering again a prior art generator to demonstrate a point, the relative velocity of the rotor to the stator is increased without increasing the absolute rotational velocity of the rotor. For example, in a prior art generator the rotor rotates within a stationary stator to generate electrical power. In order to increase the relative velocity of the rotor with reference to the stator it is necessary to increase the rotational velocity of the rotor. According to the present invention, the rotational velocity of the rotor is not altered but the stator is rotated about the rotor and in the opposite direct to that of the rotor.

Thus, if the rotor is rotated clockwise at 1 ,000 rpm and the stator is rotated at 1 ,000 rpm counter-clockwise the velocity by which each component passes each other is effectively doubled. Accordingly, a greater amount of electrical power is generated without increasing the rotational velocity of the rotor. Advantageously, this allows for the use of mechanical means which are operable (or at least more efficiently operable) at lower rotational velocities to drive the generator. Generally, the electric machine is configured such that the first and second components are movable along a common line and in substantially opposite directions. In this way, the maximum relative velocity between the first and second components is provided, thereby optimising, or at least increasing, power generation efficiency.

In one embodiment, the first and second components are rotatable about a common axis such that first component is spatially disposed within the confines of the second component. For example, a rotor having an armature may rotate within the confines of a stator establishing a magnetic field about the armature. Alternatively, the armature may surround a magnet with both components rotating about a single axis in opposite directions.

According to one embodiment of the invention, both the armature component and the magnetic field component contra-rotate about a common axis. Where the armature component is embodied in the form of a rotor, a simple axle extending through the rotational axis of the rotor is all that is required to provide the required rotational power. The contra- rotation of the magnetic field component may be provided by any means known to the skilled artisan.

The magnetic field component may be suspended within a frame such that the distance between the armature and magnetic field components remains fixed. Alternatively, the magnetic field component may be supported by the axle extending through the armature component.

The contra-rotation of the magnetic field component may be provided by simply disposing a rotating roller against the outer face of a barrel-shaped magnetic field component. Rotation of the roller (driven by whatever means) causes the barrel-shaped magnetic field component to rotate in the opposite direction to the roller.

In place of a roller, a toothed cog may be used with the outer face of the barrel-shaped magnetic field component being encircled by a toothed ring capable of meshing with the cog.

The magnetic field component may contra-rotated to the armature component by a drive shaft. The rotating magnetic field component may be stabilised by several rollers disposed about the circumference of the component, the rollers contacting and rotating with the outer face of the component. The present electric machine may be configured so that the armature and magnetic field components are driven by different sources of kinetic energy. For example, the armature component may be rotated by a first engine and the magnetic field component contra-rotated by a second engine, the first and second engines being in no way coupled.

However, it is preferred that the armature and magnetic field components are driven by a single source of kinetic energy, this arrangement providing potentially greater efficiencies in power generation. Applicant has discovered that an internal combustion engine capable of contra-rotational output provides surprising advantage as a source of kinetic energy in an electric machine of the present invention. Accordingly, the electric machine may be configured so as to mechanically couple with an internal combustion engine capable of contra-rotational output. The engine outputs may be co-axial, with the electric machine configured to be driven by such an output. For example, the axle of the armature component may be configured to couple with central co-axial output shaft of the engine, while the magnetic field component is driven contra-rotationally by a shaft surrounding the central co-axial shaft of the engine. Such couplings may be in any form which allows for the transmission of power from the engine to the armature component or magnetic field component. Thus, the armature component or magnetic field component will comprise a first part of a coupling, the first part configured to interact with a second part of the coupling attached to the engine. The coupling may be a rigid coupling of the type known to join two shafts within a motor or mechanical system, or a flexible coupling where movement or give is expected between the shafts.

Rigid couplings are preferred to maximize performance and increase the expected life of the hardware. These rigid coupling may be a sleeve-style coupling consisting of a single tube of material with an inner diameter that is equal in size to the shafts to be coupled.

Clamped or compression rigid couplings may be useful. These couplings come in two parts and fit together around the shafts to form a sleeve. They offer more flexibility than sleeved models, and can be used on shafts that are fixed in place. Flanged rigid couplings are designed for heavy loads or industrial equipment. They consist of short sleeves surrounded by a perpendicular flange. One coupling is placed on each shaft so the two flanges line up face to face. A series of screws or bolts can then be installed in the flanges to hold them together. Because of their size and durability, flanged units can be used to bring shafts into alignment before they are joined together. Rigid couplings are preferred when precise shaft alignment is required.

A gear coupling may be used in some embodiments. The gear coupling may be a mechanical device for transmitting torque between two shafts that are not collinear, or modification to speed or torque is required.

The electric machine of the present invention may further provide means for conveying the electrical power from the electric machine. As will be appreciated, in a prior art generator the stator is stationary and so it is typical for electrical terminals (a positive terminal and a negative terminal) to be disposed on the outside of the stator casing. This allows conduits (such as cables or wires) to be attached to the generator to convey the generated electrical power.

In the present invention, the incorporation of a moving magnetic field component raises a further technical problem as to a mechanism for conveying the generated electrical power from the armature windings to an external battery or other system requiring the power. One solution to that technical problem is to incorporate conductive regions (for example a first region for conducting positive charge and a second region for conducting a negative charge) into an external housing of the generator. The conductive regions are positioned, shaped, fabricated or otherwise configured so as to allow external contact means to make electrical contact while both the magnetic field component and the armature component are rotating in opposite directions.

In one embodiment, the magnetic field component is disposed within a housing, the housing having an outwardly-oriented face. The housing may be fabricated from a non-conductive material with appropriate structural characteristics (such as a high density plastic) with two conductive regions disposed therein (one to convey positive charge, and the other to convey negative charge). Each conductive region may be fabricated from a metal member extending from the inner surface of the housing to the outer surface. Each conductive region may be disposed at an end face of the housing, and may be annular, with one annular region disposed within the other, both annular regions sharing a common centre. Alternatively, where the housing is generally cylindrical, a conductive region may be embodied in the form of a band running circumferentially around the external cylinder wall. Alternatively, the housing may be fabricated from a conductive material (such as a metal), formed in two parts, with an annular insulating ring disposed between the two halves. Thus, one half of the metal housing forms a first conductive region and the second half forms a second conductive region.

In another embodiment, the housing may be fabricated completely from a conductive material, with an insulated wire being used to convey electrical power from the inner face of the housing to the external face. The external face of the conductive housing may be coated in a non- conductive material (such as a plastic) with a conductive surface being applied to the outside of the non-conductive coating. The terminal of the insulated wire is electrically connected to the conductive surface so as to form an electrically live region on an external face.

The conductive region may be fabricated from any material having sufficient conductivity for suitability in the present invention. Preferably the material is resistant to wear given that in use, the conductive region is moving but in contact with stationery external means for picking up the electrical power generated by the electric machine. Metals such as copper, aluminium, zinc, iron, and alloys therefore will find use as will non-metals such as carbon (including the allotrope graphite). The skilled person may conceive of other means for conveying electrical power from the armature component to a battery or system external to the electric machine of the present invention. All such means are included in the scope of the present invention.

The means for contacting the conductive regions may be any contrivance capable of making electrical contact with a moving conductive region. In one embodiment, the means for contacting the region is a brush, of any of the well known to the skilled artisan. Graphite brushes are an exemplary form of the many types of brushes used in electrical applications.

Typically, the brush will sacrificially wear in preference to the conducting region of the housing and so will generally be a replaceable component of the electric machine.

Other types of brushes such as those composed of metal fibre are also contemplated to be useful in the context of the present invention. Electrical noise (interference) may result from the movement of the brushes over the conductive regions of the housing. Where such noise causes problems (for example with regards to radio communications, or interference with proximal electronic equipment) an shield may be placed about the electric machine. The shield may reduce the coupling of radio waves, electromagnetic filed and electrostatic fields.

In another aspect the present invention provides an electric machine-engine combination comprising the electric machine as described herein and at least one engine, the electric machine and engine(s) being mechanically coupled such that the first and second components are moved relative to each other.

Such embodiments may form a so-called "genset" and find broad applicability in standalone electrical generation applications such as supplying power needs remote from an electrical grid, backup power generation, supplying electrical power on ships and other mobile platforms, et cetera. It will be understood that the role of the engine (or engines) is to move (and typically rotate) one or both of the magnetic field component and the armature component. The engine may be driven by any form of kinetic energy (such as a water driven turbine) or by chemical energy (such as an internal combustion engine). In any event, it is proposed that a greater amount of electrical power may be generated by the present invention for a given unit of input energy (be it kinetic energy or electrical energy). The point of comparison for that advantage may be the amount of electrical power generated by an identical genset whereby either the magnetic field component rotates relative to the armature component or the armature component rotates relative to the magnetic field component.

In one embodiment the engine is a co-axial crankless engine having: at least one cylinder defining a longitudinally extending axis; a pair of pistons positioned to reciprocate in opposite directions along the longitudinal axis of said cylinder, a space between said pistons defining a common combustion chamber; a first shaft positioned substantially parallel to and spaced laterally from the longitudinal axis of said cylinder; a second shaft positioned substantially parallel to and spaced laterally from the longitudinal axis of said cylinder, said second shaft having a longitudinally extending bore through which said first shaft can extend and rotate, each said piston being connected to an axially spaced cam, a first said cam being supported by said first shaft, a second said cam being supported by said second shaft, whereby in use reciprocation of said pistons imparts on respective shafts rotating motion in opposite directions to drive said engine. In one embodiment, the engine comprises a plurality of cylinders located about the shafts. In one embodiment, the engine comprises two cylinders and four pistons, the pistons in one cylinder operating 180° out of phase with the pistons in the other cylinder.

In one embodiment, the engine comprises three cylinders and six pistons arranged in a delta formation equally spaced about the shafts.

In one embodiment, the engine comprises four or more cylinders.

In one embodiment, the engine comprises the cams are mirror images of each other.

In one embodiment, the engine comprises the cams are single lobe, multi-lobe, swash plate, wobble plate or sinusoidal cams. Preferably, the pistons in opposite cylinders located on the same side of the engine as each other are connected to the same cam. In one embodiment, the engine comprises the pistons drive the cams in opposition directions creating coaxial counter-rotation of the shafts.

In one embodiment, the engine comprises the first shaft is supported by a first frame, the second shaft being supported by a second frame.

In one embodiment, the engine comprises a first gear operatively associated with said first shaft.

In one embodiment, the engine comprises a second gear operatively associated with said second shaft.

In one embodiment, the engine comprises the first and second gears attached to said shafts are linked by means to ensure timing synchronisation between the shafts. In one embodiment, the engine is substantially that described in international patent application PCT/AU2010/000324 (to POWELL) which published as WO/2010/1 18457; the contents of which is herein incorporated by reference in its entirety.

In another embodiment, the engine is substantially that described in Australian patent 629238 (to POWELL); the contents of which is herein incorporated by reference in its entirety. Coaxial drive systems/gearboxes driven by conventional single direction engines have been known in the art for many decades. To the best of the Applicant's knowledge, the prior art being devoid of any contra-rotating coaxial engine/coaxial genset combination. In some embodiments, the engine is not capable of contra-rotational output. In these cases, the mono-directional single output may drive a gear box (in additional to the armature component or the magnetic field component), the gear box being configured so as to reverse the direction of the rotational output of the engine. This reversed rotational output is used to drive the component which is not already driven by the main engine output.

Alternatively, two discrete engines may be used to contra-rotate the armature component and the magnetic field component.

Embodiments using two engines, or a single engine using gearing may not achieve fuel savings as significant as embodiments utilizing a single engine capable of contra-rotational output.

Irrespective of fuel savings, some embodiments of the present invention provide other advantages. One advantage is that engines are required to provide lower rotational speeds in order to achieve the same relative movement between the magnetic field component and the armature component. For example, contra-rotating the stator and armature at the same speed effective doubles the velocity at which the armature windings travel past the stator magnets. Accordingly, the engine(s) driving the components are required to only rotate at half the rotational speed that would otherwise be required to achieve the same velocity at which the armature windings travel past the stator magnets. It is possible therefore to pair a generator with an engine having a lower rotational speed, thereby broadening the types of engines that may be utilized for power generation. Lower speed engines are typically less expensive and/or complex and therefore provide economic advantages, or have lower maintenance requirements. Furthermore, lower speed engines (or higher speed engines transmitting power through a speed reduction gearbox) are able to produce higher torque.

A further advantage is that contra-rotation of the armature component and the magnetic field component facilitate air cooling of the generator. As is known in the art, generators produce heat during use with many being cooled by water recirculation circuits. Smaller generators can be air-cooled, however in situations of elevated ambient temperature undesirable heat can build up in a generator. Movement of the magnetic field component in an electric machine of the present invention causes agitation of air at the air/generator interface thereby acting to dissipate heat more effectively. In some embodiments, the generator housing may comprise scooped air vents to channel surrounding air into the generator, or external blades which act to push heated air away from the generator. The present invention also provides as another aspect methods of generating electrical power, the method comprising providing an armature component and a magnetic field component, moving the first component relative to the second component, and moving the second component relative to the first component so as to generate electrical power, wherein the first and second components are moved alone a line and in different directions.

The method may include as a step providing an electric machine as described herein or an electric machine-engine combination as described herein, and operating same under conditions known to the skilled person in order produce electricity. In one embodiment of the method, where the engine of an electric machine-engine combination is capable of providing contra-rotational output, the method provides a fuel saving for each unit of electrical power generated compared with a substantially identical electric machine-engine combination configured such that only the first electric machine component moves relative to the second electric machine component, or the second electric machine component moves relative to the first.

Furl savings may be at least about 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 1 1 %, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21 %, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31 %, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, 40%, 41 %, 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, or 50%. Preferably, fuel savings are between about 40% and about 50%.

The electric machine or electric machine-engine combination or method of the present invention may be configured or operated to provide a desired output or electrical power. In some embodiments the output is at least 500W, 1 kW , 2kW , 3kW , 4kW , 5kW , 6kW , 7kW , 8kW , 9kW , 10kW , 15kW , 20kW , 25kW , 50kW , 75kW , 100kW , 125kW , 150kW , 175kW , 200kW , 225kW , 250kW , 275kW , 300kW , 325kW , 350kW , 375kW , 400kW , 425kW , 450kW , 475kW , 500kW , 600kW , 700kW , 800kW , 900kW , 1 MW, 2MW , 3MW , 4MW , 5MW , 6MW , 7MW , 8MW, 9MW or 10MW. Preferably, the output is between about 5kW and 3.5MW. Given the present disclosure the skilled person will be amply enabled to select an engine having a sufficient capacity and/or an armature of sufficient capacity and/or a magnetic field of sufficient capacity in order to achieve a required output. The present electric machine may be utilised as an engine where an electrical current is applied to the armature component. Current is applied such that the armature component and magnetic field component rotate in opposite directions, thereby acting as an engine having contra-rotational output. The contra-rotational output may be used in any way, however in a preferred embodiment the output is used to drive a pump or similar contrivance requiring contra-rotational input.

It will be appreciated that in the description of exemplary embodiments of the invention, various features of the invention are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure and aiding in the understanding of one or more of the various inventive aspects. This method of disclosure, however, is not to be interpreted as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive aspects lie in less than all features of a single foregoing disclosed embodiment. Furthermore, while some embodiments described herein include some but not other features included in other embodiments, combinations of features of different embodiments are meant to be within the scope of the invention, and form different embodiments, as would be understood by those in the art. For example, in the following claims, any of the claimed embodiments can be used in any combination.

In the description provided herein, numerous specific details are set forth. However, it is understood that embodiments of the invention may be practiced without these specific details. In other instances, well-known methods, structures and techniques have not been shown in detail in order not to obscure an understanding of this description.

Thus, while there has been described what are believed to be the preferred embodiments of the invention, those skilled in the art will recognize that other and further modifications may be made thereto without departing from the spirit of the invention, and it is intended to claim all such changes and modifications as fall within the scope of the invention. Functionality may be added or deleted from the block diagrams and operations may be interchanged among functional blocks. Steps may be added or deleted to methods described within the scope of the present invention. Although the invention has been described with reference to specific examples, it will be appreciated by those skilled in the art that the invention may be embodied in many other forms. The present invention will now be more fully described by reference to the following non- limiting preferred embodiments.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION Figure 1 shows an electric machine-engine combination according to a preferred embodiment of the invention. The engine 10 is capable of contra-rotational output via a first drive shaft 12 and a second drive shaft 14. The first shaft has associated bearings 16, and the second shaft has associated bearings 18. As will be noted the first and second shafts a coaxial, with the first shaft extends through and rotates within a bore of the second shaft. The terminus of the first shaft is stabilised by insertion into a bearing retained in a support structure 19.

The electric machine-engine combination further comprises a generator 30 comprising a magnetic field component comprising a housing 32 having permanent magnets 34. The generator 30 further comprises an armature component 36 configured to rotate within the magnetic field provided by the permanent magnets 34.

The generator includes a standard commutator arrangement for conveying the generated electrical power from the generator. The commutator arrangement comprises two slip rings 40 and 42 about the first drive shaft, each slip ring making electrical contact with a brush 44 and 46. Each brush is connected by an electrical conduit to an annular portion 48 and 50 of the housing which is electrically conductive. Disposed outside the generator 30 are two external brushes 52 and 54 making electrical contact with the conductive annular portions 48 and 50.

In use, the magnetic field component housing 32 and permanent magnets 34 are caused to rotate by the second drive shaft 14, and the armature component 36 is caused to contra-rotate by the first drive shaft to generate electrical power. Upon rotation, a positive charge forms at the annular portion 48 and a negative charge at annular portion 50. In turn, these positive and negative charges are conveyed to the external brushes 52 and 54, with the terminal of each brush being connected to electrical conduit (not shown) for supply to a battery or other system requiring electrical power.

The housing 32 is fabricated from a substantially non-conductive material to prevent any leakage of charge or shorting between the annular portions 48 and 50.

Fig. 2 shows more clearly the arrangement by which electrical power is conveyed from the generator. This figure shows an end-on the housing 32 with conductive annular portions 48 and 50. The first drive shaft is shown at 12. The areas of contact of the external brushes 52 and 54 in shown by the outlines so marked.

In use, the engine 10 is started and set to the required rotational speed. This sets the contra- rotation of the first 12 and second 14 drive shafts. The first draft shaft 12 is directly coupled to the housing of the magnetic field component 32, thereby turning the housing 32 and also the magnets 34 in a first direction. Concomitantly the second shaft 14 is rotated in the opposite direction to cause contra-rotation of the armature 36. Electrical current is thereby generated in the armature windings, with the current being taken up by the internal brushes 44, 46 conveyed to the conductive regions 48 and 50, and taken up in turn by external brushes 52 and 54.

Claims

CLAIMS:

1 . An electric machine comprising an armature component and a magnetic field component, the armature and magnetic components being movable relative to each other so as to generate electrical power, wherein the electric machine is configured such that component is movable relative to the second component, and the second component is movable relative to the first component, wherein the first and second components are movable along a line and in different directions.

2. The electric machine of claim 1 configured such that the first and second components are moveable along a common line and in substantially opposite directions.

3. The electric machine of claim 1 or claim 2 wherein the first and second components rotate about a common axis.

4. The electric machine of claim 3 wherein the first component rotates within the confines of the second component.

5. The electric machine of clam 3 wherein the first and/or second components are configured to connect to a source of mechanical rotational power.

6. The electric machine of any one of claims 3 to 5 wherein the first and second components are configured to connect to a single source of mechanical rotational power.

7. The electric machine of claim 6 wherein the source of mechanical rotation is an engine.

8. An electric machine-engine combination comprising the electric machine of any one of claims 1 to 7 and at least one engine, the electric machine and engine(s) being mechanically coupled such that the first and second components are moved relative to each other.

9. The electric machine-engine combination of claim 8 consisting of a single engine, the single engine and electric machine being mechanically coupled such that the single engine moves the first and second components.

10. The electric machine-engine combination of claim 8 or claim 9 wherein the engine is an internal combustion engine.

1 1 . The electric machine-engine combination of claim 6 or claim 7 wherein the engine is capable of providing contra-rotational output.

12. The electric machine-engine combination of claim 9 wherein the first rotational direction of the contra-rotational output is mechanically coupled to the first electric machine component, and the second rotational direction of the contra-rotational output is mechanically coupled to the second electric machine component.

13. A method of generating electrical power, the method comprising providing an armature component and a magnetic field component, moving the first component relative to the second component, and moving the second component relative to the first component so as to generate electrical power, wherein the first and second components are moved alone a line and in different directions.

14. The method of claim 13 comprising use of the electric machine of any one of claims 1 to 7,

15. The method of claim 13 comprising use of the electric machine-engine combination of any one of claims 8 to 12.

16. The method of claim 15, wherein where the engine of the electric machine-engine combination is capable of providing contra-rotational output, the method provides a fuel saving for each unit of electrical power generated compared with a substantially identical electric machine-engine combination configured such that only the first electric machine component moves relative to the second electric machine component, or the second electric machine component moves relative to the first.

17. The method of claim 16 wherein the fuel saving is at least about 1 %, or at least about 2%, or at least about 3%, or at least about 4%, or at least about 5%.

18. The method of claim 16 wherein the fuel saving is at least about 10%, or at least about 15%, or at least about 20%, or at least about 25%.

19. Electrical power in usable or vendible form produced by the method of any one of claims 13 to 18.

20. A method of providing mechanical contra-rotational output, the method comprising the steps of providing the electric machine of any one of claims 1 to 7, applying an electric current two the armature component under conditions such that the armature component and magnetic field component contra-rotate relative to each other.