Field of Invention The invention relates to a method for a generator for the production of electricity, in particular, but not necessarily limited to, electricity from wind energy.

Background The use of turbines to generate electricity from wind is known. In general, wind turbines operate by arranging a rotor to rotate in response to wind flowing over vanes of the turbine. This, in turn, causes rotation of a drive shaft. The drive shaft causes turning of a rotor relative to a stator with a magnetic field, thus generating electricity. Known wind turbines are reasonably efficient in producing electricity in moderate-to- high wind speeds. Producing electricity in lower wind speeds is more problematic. The need for sufficient rotational speed of the drive shaft is usually met by providing larger turbine vanes, in order to obtain increased torque.

An aim of the invention therefore is to provide an electricity generating apparatus which can produce electricity from relatively low wind speeds while remaining relatively compact in size.

Summary of Invention

According to an aspect of the present invention there is provided a generator including: at least one input rotor;

at least one armature component;

at least one field magnet component;

at least one of the components being in the form of an output rotor;

at least one of the components being in the form of an output stator or further output rotor; and

a gearing arrangement for converting torque from the at least one input rotor to torque on at least one output rotor;

rotation of the at least one output rotor relative to the at least one output stator or further output rotor generating electricity due to magnetic field interaction between opposed planar faces of armature and field magnet components;

characterised in that electricity is also generated due to magnetic field interaction around the circumference of at least one output rotor as it rotates, and/or at least one output rotor and at least one further output rotor are arranged to rotate in opposite directions. In one embodiment the at least one input rotor is a wind turbine.

In one embodiment the gearing arrangement includes two bevel driven gears arranged to rotate in opposite directions in conjunction with the at least one output rotor and at least one further output rotor.

In one embodiment the generator comprises a first input rotor and a second input rotor being arranged to rotate in opposite directions.

In one embodiment the at least one input rotor is arranged to rotate about a first axis, and the at least one output rotor and the at least one further output rotor are arranged to rotate about a second axis. In one embodiment the second axis is perpendicular to the first axis. In an alternative embodiment the second axis is parallel to the first axis.

In one embodiment two input rotors are provided in the form of wind turbines arranged with parallel wind entries for directing wind to opposite sides of the respective turbines.

In an embodiment where two input rotors are provided, the gearing arrangement includes a further two bevel drive gears arranged to rotate in opposite directions in conjunction with the first and second input rotors.

In one embodiment at least one output rotor and the at least one output stator or further output rotor may each be arranged on respective shafts, with one of the shafts being hollow and arranged to locate about the other shaft. It will be appreciated by the person skilled in the art that other arrangements may be utilised for the same effect, and a shaft need no necessarily be hollow.

In one embodiment the gearing arrangement includes five gears arranged to rotate the at least one output rotor and at least one output stator in opposite directions. Typically the gearing arrangement comprises a first large gear mounted on the hollow shaft, a first small gear mounted on the other shaft, a stepped gear comprising a second large gear and a second small gear, the second large gear engaging the first large gear, and a third small gear engaging the first small gear and the second small gear.

Advantageously this gearing arrangement can be oil lubricated. Typically the counter rotation of the two shafts is at the same speed but it will be appreciated by the person skilled in the art that other gear ratios may be used to allow the shafts to rotate at different speeds.

In one embodiment the output rotors and/or stators are substantially disc shaped. In a further embodiment at least one of the output rotors and/or stators is cylindrical. In one embodiment an output rotor is located between two output stators. Typically the output rotor is two-sided, with a first side facing a first output stator and a second side facing a second output stator. In an alternative embodiment, an output stator is located between two output rotors. Typically the output stator is two-sided, with a first side facing a first output rotor and a second side facing a second output rotor.

In one embodiment of the invention at least one of the output rotors or stators has permanent magnets located on one or both sides, and at least another has electrical coil windings mounted on one or both sides, such that each surface with permanent magnets opposes a surface with electrical coil windings.

In one embodiment the generator may include a plurality of output rotors and/or stators, with an outermost rotor or stator at each axial end being one sided, and inner rotors and stators each being two sided.

In one embodiment the at least one rotor and at least one stator or further output rotor are located within a generally cylindrical inner housing. Typically at least one output rotor is mounted on the inner housing such that the inner housing is rotated thereby.

In one embodiment, the inner housing is located within a generally cylindrical outer housing, such that the outer surface of the inner housing and the inner surface of the outer housing are opposed.

In one embodiment permanent magnets are mounted on one of the opposed housing circumferential surfaces, and windings are mounted on the other circumferential surface. Therefore as the inner housing rotates inside the outer housing, electricity is produced from the relative movement between the permanent magnets and the windings.

In a further embodiment one or more output rotors and/or stators are located within a generally cylindrical outer housing, permanent magnets being mounted around the outer circumference of the rotor or the inner circumference of the housing, and windings being opposedly mounted around the other circumference. Advantageously this produces electricity from the circumferential magnetic interaction, in addition to the planar magnetic interaction as hereinbefore described.

In one embodiment the rotor within the inner housing is generally cylindrical and the end surfaces of the inner housing oppose the planar surfaces of one or more output rotors and/or stators coaxially located adjacent the inner housing, permanent magnets being mounted on one of the opposed surfaces, and windings being mounted on the other surface.

In a further aspect of the invention there is a provided a motor with a generator as herein described integrated therewith. Advantageously the generator is not a separate unit. For example, the generator may be integrated into a pump for a dam so that the pump can also provide electricity for light. It will be appreciated that the generator may be integrated into many different types of motor. In one embodiment the motor is provided with a flywheel adapted into an armature and/or field magnet component. For example permanent magnets may be fitted to the flywheel to turn it into a field magnet component similar to the rotor discs described herein. In a yet further aspect of the invention there is provided a gearbox comprising a gearing arrangement including at least five gears:

a first large gear mounted on a hollow outer shaft,

a first small gear mounted on an inner shaft coaxial to and running through the outer shaft;

a stepped gear comprising a second large gear and a second small gear, the second large gear engaging the first large gear; and

a third small gear engaging the first small gear and the second small gear; characterised in that the gears cause the inner shaft and outer shaft to be rotated in opposite directions.

Brief Description of Drawings

It will be convenient to further describe the present invention with respect to the accompanying drawings that illustrate possible arrangements of the invention. Other arrangements of the invention are possible, and consequently the particularity of the accompanying drawings is not to be understood as superseding the generality of the preceding description of the invention.

Figure 1 is a rear perspective of a generator according to an embodiment of the invention. Figure 2 is a cross section through a turbine of the generator of Figure 1. Figure 3 a is a phantom perspective of the generator of Figure 1.

Figure 3b is a front view of an alternative arrangement of a generator in accordance with the present invention.

Figure 4 is a plan cross section through the generator of Figure 1.

Figure 5 is an energy converter from within the generator of Figure 1.

Figure 6 is a perspective of a rotor within the energy converter of Figure 5. Figure 7 is a side view of the rotor of Figure 6. Figure 8 is a perspective of a stator within the energy converter of Figure 5. Figure 9 is a side view of the stator of Figure 8. Figure 10 is a schematic view of an internal configuration of the energy converter of Figure 5.

Figure 11 is a side cross sectional view of the energy converter of Figure 5.

Figure 12 is a plan cross sectional view of the energy converter of Figure 5.

Figure 13 is an alternative energy converter for use in a generator in accordance with an embodiment of the invention.

Figure 14 is a perspective of a rotor within the energy converter of Figure 13.

Figure 15 is a perspective of a stator within the energy converter of Figure 13. Figure 16 is a plan cross sectional view of the energy converter of Figure 13; (a) side view; (b) cross-sectional view of section P-P.

Figure 17 is a perspective of an alternative rotor arrangement within the energy converter of Figure 13.

Figure 18 is a perspective of an alternative rotor arrangement for use in conjunction with the rotor of Figure 17.

Figure 19 is a plan cross sectional view of the energy converter of Figure 13, using the rotors of Figure 17-18; (a) side view; (b) cross-sectional view of section P-P.

Figure 20 is an exploded view of an alternative energy converter according to an embodiment of the invention. Figure 21 is a further exploded view of an alternative energy converter of Figure 20.

Figure 22 is a further exploded view of the outer housing of Figure 20. Figure 23 is a view of the energy convertor with a lateral drive according to an embodiment of the invention (a) side view; (b) cross-section through Y-Y; (c) cross- section through Z-Z; (d) isometric. Figure 24 is a view of the energy convertor with a direct drive according to an embodiment of the invention (a) side view; (b) cross-section through Y-Y; (c) cross- section through Z-Z; (d) isometric.

Figure 25 illustrates a gearing arrangement: (a) partially exploded view; (b) sectional view.

Figure 26 is an exploded view of an alternative energy converter with a direct drive according to an embodiment of the invention. Figure 27 is a view of the energy convertor with a direct drive according to an embodiment of the invention (a) side view; (b) cross-section through C-C; (c) cross- section through D-D.

Figure 28 is an exploded view of an alternative energy converter with a lateral drive according to an embodiment of the invention.

Figure 29 is a schematic cross-sectional side view of a further alternative energy convertor in accordance with a further embodiment of the invention. Figure 30 is a schematic cross-sectional side view of a yet further alternative energy convertor in accordance with a further embodiment of the invention.

Detailed Description Referring to the Figures, Figure 1 shows a wind powered electricity generator 10. The generator has a first turbine section 12 and a second turbine section 14, with an energy converter 16 separating the two turbine sections 12, 14. The first turbine section 12 is shown in cross section in Figure 2. It has an outer casing 18 having a generally funnel-shaped wind entry opening 20, and a wind exit opening 22. The outer casing 18 contains a first turbine rotor 24, mounted on a first shaft 26. The first turbine rotor 24 is a drag-powered turbine, having blades with one concave and one convex side, although it will be appreciated that a lift-powered turbine could also be used.

The wind entry opening 20 has an outer diameter equal to about 75% of the diameter of the first turbine rotor 24. It narrows to have an inner diameter similar to the radius of the first turbine rotor 24, with wind entering the wind entry opening 20 being directed to one side of the first turbine rotor 24, onto the concave side of the turbine blades.

The wind exit opening 22 is displaced from the wind entry opening by about 120° about the first shaft 26.

As can be seen from Figures 3a and 4, the second wind turbine section 14 is similar in construction to the first wind turbine section 12, having a second turbine rotor 28 mounted to a second shaft 30. The second wind turbine section 14 is arranged oppositely to the first wind turbine section 12, such that its wind entry and exit openings 20, 22 are reflected relative to those of the first wind turbine section 12, and the second turbine rotor 28 and second shaft 30 are arranged to rotate in the opposite direction to the first turbine rotor 24 and the first shaft 26.

An alternative arrangement of wind turbine sections 12 and 14 is shown in Figure 3b. In this arrangement the first and second turbine rotors 24 and 26 are arranged to rotate about axles 27 which are parallel to the direction of wind flow. The axles are linked by a bevelled gearing arrangement (not shown) to provide impetus to first and second shafts 26, 30 which are perpendicular to the axles 27 of rotation. With reference to Figure 5, the energy converter 16 houses an electrical generating apparatus including a field magnet component in the form of first rotor 32 and an armature component in the form of second rotor 34. The first rotor 32, which can be seen in Figures 6 and 7, includes a rotor shaft 36 onto which is mounted a first bevel gear wheel 38 and a first rotor disc 40. The first rotor disc 40 includes a plurality of permanent magnets 42, spaced around the first rotor disc 40, on a side of the disc facing the first bevel gear wheel 38. The permanent magnets 42 are each oriented radially. The first bevel gear wheel 38 and the first rotor disc 40 are spaced apart along the rotor shaft 36, with a gap 44 between them.

The second rotor 34, which can be seen in Figures 8 and 9, includes a second bevel gear wheel 46 and a second rotor disc 48. The second bevel gear wheel 46 and the second rotor disc 48 are mounted next to each other axially along a common, hollow shaft 50. A spacer 52 is mounted axially adjacent the second bevel gear wheel 46, on the opposite side to the second rotor disc 48.

The second rotor disc 48 includes a plurality of windings 54, spaced around the second rotor disc 48, on a side of the disc facing away from the second bevel gear wheel 46.

The first rotor 32 and second rotor 34 are arranged coaxially, as shown in Figures 10 and 11, with the second rotor 34 located in the gap 44, and the hollow shaft 50 located about the rotor shaft 36. When thus arranged, the planar faces of the rotors are located opposite each other such that the permanent magnets 42 locate axially adjacent the windings 54, and the first and second bevel gear wheels 38, 46 are oriented towards each other, and spaced by the spacer 52.

The first rotor shaft 36 is supported by outer bearings 56 located in the housing of the energy converter 16, and is able to freely rotate about its longitudinal axis. The second rotor shaft 50 is located in a sliding fit over the first rotor shaft 36, and is able to freely rotate relative to the first rotor shaft 36 about the longitudinal axis.

The energy converter 16 is arranged such that the first rotor shaft 36 is perpendicular to the first shaft 26 of the first turbine section 12 and the second shaft 30 of the second turbine section 14, as illustrated in Figure 12. The arrangement is such that the first shaft 26 extends into the energy converter 16 through a side wall 58 thereof. The energy converter 16 includes inner bearings 60 which support the first shaft 26 transversely to the first rotor shaft 36. The first shaft 26 is generally positioned to align with the spacer 52. A first bevel gear drive wheel 62 is mounted about an internal end of the first shaft 26, and is arranged to mesh with both the first bevel gear wheel 38 and the second bevel gear wheel 46.

It will be appreciated that rotation of the first shaft 26 will translate through the bevel gears into rotation of the first rotor shaft 36 in one direction and the second rotor shaft 50 in the opposite direction.

The second shaft 30 extends into the energy converter 16 through an opposite side wall 58 thereof. The bearing and gearing arrangement of the second shaft 30 is identical to that of the first shaft 26. The second shaft 30 thus has a second bevel gear drive wheel 64 located on its outer end, which is diametrically opposed to the first bevel gear drive wheel 62 across the spacer 52.

The second bevel gear drive wheel 64 and second shaft 30 will thus rotate in the contra direction to the first bevel gear drive wheel 62 and the first shaft 26.

In use, wind blowing from the entry openings 20 to the exit openings 22 of the first and second turbine sections 12, 14 will cause rotation of the first and second shafts 26, 30 in opposite directions. Through action of the bevel gears, this is translated to rotation of the rotor shafts 36, 50 in opposite directions. This causes rotation of the rotor discs 40, 48 in opposite directions, effectively doubling the relative rotational speed of the discs 40, 48 compared to holding one stationary.

Electricity is thus produced through the relative movement of the windings 54 and the magnetic fields generated by the permanent magnets 42. Electricity can be produced at relatively low wind speeds. An alternative energy converter 116 is shown in Figures 13 to 19. Although this energy converter 116 is shown with only one input shaft 126, it will be appreciated that it can be readily adapted to operate with a second input shaft in a similar fashion to the energy converter 16. The energy converter 116 houses an electrical generating apparatus including a field magnet component in the form of first rotor 132, and armature components in the form of second and third rotors 134, 135.

The first rotor 132, which can be seen in Figure 14, includes a rotor shaft 136 onto which is mounted a first bevel gear wheel 138 and a first rotor disc 140. The first rotor disc 140 includes a plurality of permanent magnets 142, spaced around the first rotor disc 140, on both sides of the disc: one side facing the first bevel gear wheel 138 and the other side facing away from the bevel gear wheel 138. The permanent magnets 142 are each oriented radially. The first bevel gear wheel 138 and the first rotor disc 140 are spaced apart along the rotor shaft 136, with a gap 144 between them. The rotor shaft 136 extends through and past the rotor disc 140, with a protruding end portion 145 on the side of the rotor disc 140 away from the bevel gear wheel 138.

The second and third rotors 134, 135, which can be seen in Figure 15, are mounted to each other by a circumferential housing 151. The second rotor 134 includes a second rotor disc 148. The third rotor 135 includes a third rotor disc 149. The second and third rotors 134, 135 are mounted to a second bevel gear wheel 146. The second bevel gear wheel 146 and the second rotor disc 148 are mounted next to each other axially along a common, hollow rotor shaft 150. A spacer 152 is mounted axially adjacent the second bevel gear wheel 146, on the opposite side to the second rotor disc 148. The second and third rotor discs 148, 149 are axially spaced apart from each other. Each armature disc 148, 149 includes a plurality of windings 154, spaced around the respective disc 148 or 149, on a side of the disc facing towards the other respective armature disc 149, 148.

The rotors 132, 134, 135 are arranged coaxially, as shown in Figure 16, with the first rotor 132 located between the other two 134, 135; the second rotor 134 located in the gap 144; and the hollow rotor shaft 150 located about the rotor shaft 136. When thus arranged, the permanent magnets 142 locate axially adjacent the windings 154, and the first and second bevel gear wheels 138, 146 are oriented towards each other, and spaced by the spacer 152. The rotor shaft 136 is supported by outer bearings 156 located in the housing of the energy converter 116, and is able to freely rotate about its longitudinal axis. The hollow shaft 150 is located in a sliding fit over the rotor shaft 136, and is able to freely rotate relative to the rotor shaft 136 about the longitudinal axis. The energy converter 116 is arranged such that the rotor shaft 136 is perpendicular to the input shaft 126. The arrangement is such that the input shaft 126 extends into the energy converter 116 through a side wall 158 thereof. The energy converter 116 includes inner bearings 160 which support the input shaft 126 transversely to the rotor shaft 136.

The input shaft 126 is generally positioned to align with the spacer 152. A first bevel gear drive wheel 162 is mounted about an internal end of the input shaft 126, and is arranged to mesh with both the first bevel gear wheel 138 and the second bevel gear wheel 146.

It will be appreciated that rotation of the input shaft 126 will translate through the bevel gears into rotation of the rotor shaft 136 in one direction and the hollow shaft 150 in the opposite direction. This causes rotation of the first rotor disc 140 in one direction and the other two rotor discs 148, 149 in the opposite direction. Effectively, this provides two electricity producing magnetic field/winding interactions, each operative at effectively double the relative rotational speed of the discs 140, 148/149 compared to holding one stationary.

Electricity is thus produced through the relative movement of the windings 154 and the magnetic fields generated by the permanent magnets 142.

Figures 17 to 19 show an alternative arrangement of the energy converter 116 in which the relative positions of the magnets and the windings have been interchanged. Figures 20 to 25 illustrate embodiments of the invention comprising an alternative energy convertor. As described previously, the energy converter includes a field magnet component comprising a rotor disc 240 on which a plurality of permanent magnets 242 are mounted, located between two armature components in the form of further rotor discs 248 on which a plurality of windings 254 are mounted, the planar surfaces on which the windings are located opposing the planar surfaces on which the magnets are mounted, such that relative movement thereof causes magnetic field interaction therebetween.

The further rotor discs are mounted on a cylindrical inner housing 251, which is located within a cylindrical outer housing 270. Permanent magnets 266 are mounted on the outside of the inner housing and windings are mounted in grooves 268 on the inside of the outer housing.

Thus when the rotor disc rotates in one direction, the further rotor discs and inner housing rotate in the opposite direction. Electricity is produced through the relative movement of the windings 254 and the magnetic field generated by the permanent magnets 242 on the respective rotors, as described previously, and additionally through the relative movement of the windings in the grooves 268 of the outer housing and the magnetic field generated by the permanent magnets 266 on the inner housing. The electricity flows through outlet connection in the form of a brush assembly and rectifier unit 276, via conductive slip rings on the rotor shaft 236 and carbon brushes on the unit 276.

The circular ends 272 of the outer housing are provided with holes 274 to assist with air cooling of the internal mechanisms.

As illustrated in Figures 23a-d the energy convertor may include a lateral drive mechanism 278 which projects from the side of the apparatus, wherein the input shaft 226 drives bevel gear wheels 238, 246 (and corresponding rotor shafts 236, 250) in opposite directions. Alternatively as illustrated in Figures 24a-d, the energy convertor may include a direct drive mechanism wherein the rotor shaft 236 projects from the end of the apparatus and is driven directly by the at least one input rotor. With reference to Figures 25a-b, a gearing arrangement is illustrated which may be used instead of the bevel gears for providing counter-rotating rotor shafts in the aforementioned examples.

The gearing arrangement includes five gears arranged to rotate the rotor shafts 236, 250 in opposite directions. Arrows indicate the direction of rotation. The gearing arrangement comprises a first large gear 282 mounted on the hollow shaft 250, a first small gear 284 mounted on the other shaft 236, a stepped gear 290 comprising a second large gear 286 and a second small gear 288, the second large gear 286 engaging the first large gear 282, and a third small gear 292 engaging the first small gear 284 and the second small gear 288. As the gear ratios on the stepped gear and the shaft gears are the same, the shafts are counter-rotated at the same speed.

The gears are fitted to a housing 280 which sealed to allow the gears to be oil lubricated, and therefore more efficient than the bevel gear arrangement due to the reduced friction

Figures 26 to 28 illustrate embodiments of the invention comprising an alternative energy convertor similar to that described previously. In this embodiment the energy convertor includes a field magnet component comprising a stator disc 294 mounted on the end 272' of the housing 270', the stator disc comprising a plurality of permanent magnets 242, a further field magnet component comprising a rotor disc 240' on which a plurality of permanent magnets 242 are mounted on the planar surface facing the stator disc 294, and an armature component in the form of further rotor disc 296 located therebetween. The armature rotor disc 296 comprises a plurality of windings 298 which are wound around spokes 299 of the disc 296, such that when the armature rotor disc is rotated relative to the other discs, magnetic field interaction is generated therebetween. The windings of the disc are considered to form planar faces of the armature opposite the permanent magnets of the other discs.

The discs are located within a cylindrical outer housing 270' which comprises windings mounted in grooves 268 on the inside thereof. Curved permanent magnets 300 are mounted around the circumference of the armature rotor disc 296 such that rotation thereof causes magnetic field interaction between the circumferential permanent magnets 300 and the windings in the grooves 268. Figure 28 illustrates a similar embodiment to that of Figures 26-27, but with a lateral drive rather than a direct drive.

Figures 29 and 30 illustrate further embodiments of the invention wherein the energy convertor includes a field magnet component comprising a cylindrical rotor 340 on which a plurality of permanent magnets 342 are mounted around its circumference.

The cylindrical rotor 340 is located within a cylindrical inner housing 351, which is located within a cylindrical outer housing 370. Permanent magnets 366 are mounted around the outer circumference and ends of the inner housing and windings 369 are mounted on the inner circumferences of the outer housing and inner housing.

The cylindrical rotor is co-axially mounted between two armature components in the form of stators 394 on which a plurality of windings 354 are mounted, the planar surfaces on which the windings are located opposing the planar surfaces on which the magnets of the inner housing 351 are mounted, such that relative movement thereof causes magnetic field interaction therebetween.

As described previously, a gearing mechanism is provided for counter-rotation wherein the input shaft 326 drives bevel gear wheels 338, 346 (and corresponding rotor shafts 336, 350) in opposite directions.

Thus when the cylindrical rotor 340 rotates in one direction, the inner housing 351 rotates in the opposite direction. Electricity is produced through the relative movement of the windings 369 on the inner housing and the magnetic field generated by the permanent magnets 342 on the cylindrical rotor 340, and additionally through the relative movement of the windings 354 on the outer housing and the magnetic field generated by the permanent magnets 366 on the inner housing, and further additionally through the relative movement of the windings 369 of the outer housing and the magnetic field generated by the permanent magnets 366 on the inner housing. Rectifers 376 may optionally be provided.

Figure 30 illustrates a similar embodiment to Figure 29, but wherein the permanent magnets on the cylinders have been replaced with windings. As rotors are counter- rotated by the input shaft 326 and bevel gears 338, 346, electricity is generated via exciter slip rings 371 which excite the field magnet component wirings via copper oxide brushes 373 and output plug 375 to generate magnetic fields (i.e. some of the wirings become electromagnets).

In this embodiment the electricity generated from the magnetic interactions flows through outlet connection in the form of a brush assembly and rectifier unit 376, via conductive slip rings 377 on the rotor shaft 336 and carbon brushes 379 on the unit 376. Throughout the specification, unless the context requires otherwise, the word 'comprise' or variations such as 'comprises' or 'comprising', will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers. Modifications and improvements can be made without departing from the scope of the invention, and variations as would be apparent to a skilled addressee are deemed to be within the scope of the present invention. For instance, the number of stators and/or rotors can be increased along the operative axle without departing from the scope of the invention.

It will be appreciated by persons skilled in the art that the present invention may also include further additional modifications made to the system which does not affect the overall functioning of the system.