WO2009125290A2

WO2009125290A2 - Electromechanical rocket

Info

Publication number: WO2009125290A2
Application number: PCT/IB2009/005226
Authority: WO
Inventors: Nyirenda Kabimba
Original assignee: Nyirenda Kabimba
Priority date: 2008-04-11
Filing date: 2009-04-06
Publication date: 2009-10-15
Also published as: WO2009125290A4; WO2009125290A3

Abstract

A device that utilizes the force on a current carrying conductor placed in a magnetic field to produce thrust without the need either to push against an external medium, surface or object, or to eject mass is disclosed. The device utilizes freedom of movement between either the current carrying conductor and the rest of the device or the source of the magnetic field and the rest of the device to prevent action and reaction from cancelling each other out. In an embodiment of the invention, windings on stators (101) act as the current carrying conductor while electromagnets on rotors (105) produce the magnetic field. The overall result is that the whole device experiences a thrust and accelerates (moves) linearly while the movable parts rotate. Various embodiments are disclosed.

Description

ELECTROMECHANICAL ROCKET

TECHNICAL FIELD

The invention concerns an electromechanical device that utilizes the force on a current carrying conductor placed in a magnetic field to produce thrust without the need either to push against an external medium, surface or object, or to eject mass. The invention further utilizes freedom of movement between either the current carrying conductor and the rest of the device or the source of the magnetic field (i.e. permanent magnets or electromagnets) and the rest of the device to prevent action and reaction from cancelling each other out. Freedom of movement is also allowed between the current carrying conductor and the source of the magnetic field. The overall result is that the whole device experiences a thrust and accelerates (moves) linearly while the movable parts rotate.

BACKGROUND ART

The force on a current carrying conductor placed in a magnetic field is currently used in electric motors. The arrangement of the coils of wire on the stator and rotor is such that a torque is generated. This torque is then used to drive a load. The motion produced is rotary. Motors are used to provide drive for linear motion but this is only achieved by providing a medium or surface against which to push. For example, the motor may drive a wheel which moves along a hard surface or a propeller that pushes against a fluid.

Electromagnets are also used to provide a linear driving force for trains that levitate above rails. The levitation is achieved by repulsion or attraction with appropriate control schemes. The interaction is between the rails and the underside of the train. The train moves as it is pulled by a moving magnetic field. The train, however, does not carry the rail alone with it. The train is therefore basically pushing against the rail, an external surface. Other forms of linear motors exist or are being developed that can launch projectiles or aircraft. The launchers, however, do not move with the projectile or aircraft. In this case also the launcher acts as an external object against which the aircraft pushes. It is not a part of the aircraft.

Currently, only conventional rockets are capable of providing a linear thrust without the need to push against an external medium or surface. However, rockets have the disadvantage that they have to expel mass in order to accelerate. Typically, conventional rockets incorporate an internal system of generating fast moving gases that are expelled from one end of the rocket. The rocket accelerates in the opposite direction to that of the expelled gas as a reaction to the action of expelling the gas.

The thrust generated by conventional rockets is not reversible - the thrust is in only one direction. Rockets have also only been applied in relatively few areas, mainly in space and military applications and fireworks. On the other hand, people encounter electric motors on a daily basis in so many gadgets. One reason for this is that electromechanical devices are simple and easy to use safely.

DISCLOSURE OF INVENTION

The invention is an electromechanical devise that generates a thrust based on the force experienced by a current carrying conductor placed in a magnetic field. The device is designed to produce a thrust on itself and on anything to which it is attached without having to push against an external medium, surface or object, or to eject mass. The invention consists of one or several current carrying conductors and one or several sources of magnetic field.

The current carrying conductors and sources or magnetic field are attached to the same base or frame such that the force on the current carrying conductors is experienced by the whole device. There is a reaction force which acts on the sources of the magnetic field. If action and reaction are present on the same device, the two being equal and opposite will cancel out, thus no overall resultant thrust would be experienced. The present invention, however, prevents action and reaction from cancelling each other out by allowing the source of the magnetic field freedom of movement in one direction relative to the rest of the device. The freedom to move in one direction means that the movable part acts as an "external" object in that direction. However, in order for it to move along with the rest of the device, the free-to-move part must be fixed to the rest of the device. This conflict is resolved by having the direction in which the moveable part is free to move and the direction in which it is fixed to be orthogonal to each other.

Furthermore, the freedom to move is not linear. If it were linear, the free- to-move part would eventually exit the device much the same way as the fast moving gases of a conventional rocket (which are free to move relative to the rocket) eventually exit the rocket. In the present invention, the movable part is therefore free to move in an angular direction. Thus rotors, in the best mode of carrying out the invention, carry the sources of the magnetic fields. The rotors are fixed in both the radial and axial directions.

This arrangement ensures a continuous rotary motion for the sources of the magnetic field and a continuous or continual force on the current carrying conductors which constitute a stator or stators. The stators are fixed to the rest of the device in all directions. The force on the stators thus constitutes the overall thrust on the device. The effect would be similar if the source of the magnetic field were fixed and the current carrying conductor placed on the rotors.

Various embodiments of the invention are disclosed including a best mode of carrying out the invention. Also disclosed are methods of controlling the generated thrust and the rotational speed of the rotors. The embodiments presented are only examples of possible configurations. Many other configurations and arrangements are possible.

BRIEF DESCRIPTION OF DRAWINGS

The invention is illustrated in the accompanying drawings attached at the end of the document wherein,

Fig. 1 is a front elevation of an embodiment of the Electromechanical Rocket, with the casing cut open revealing internal components. The brushes and bearings are not shown.

Fig. 2 is a side elevation of an embodiment of the Electromechanical Rocket with casing cut open revealing internal components.

Fig. 3 is a sectioned plan elevation of an embodiment of the Electromechanical Rocket.

Fig. 4 illustrates Cartesian and Cylindrical Coordinate Systems.

Fig. 5 is an end view of an alternative rotor with 8 equally spaced electromagnets. The rotor has an octagonal shape.

Fig. 6 is a schematic drawing showing the directions of magnetic field from an electromagnet on the rotor and current in the stator coil.

Fig. 7 is a schematic drawing of the rotors and stators of an embodiment of the Electromagnet Rocket, showing the forces involved. The casing and other features are not shown.

Fig. 8 is a schematic drawing showing the forces on the rotor.

Fig. 9 is a sectioned Front view of an alternative rotor with a ring pole electromagnet

Fig. 10: is an end view of an alternative rotor with a ring pole electromagnet Fig. 1 1 is a schematic drawing of alternative rotors with ring pole electromagnets and showing some forces involved.

Fig. 12 is a drawing showing a configuration of a single rotor and stator.

Fig. 13 is a drawing showing a single stator with multiple rotors as an alternative configuration.

Fig. 14 is a drawing showing a wide pole electromagnet.

Fig. 15 is a sectioned top view of a brushless arrangement where magnetism is induced into rotor pieces of high magnetic permeability. The rotors do not have electromagnets attached to them.

Fig. 16 is an end view of the brushless arrangement.

MODES FOR CARRYING OUT THE INVENTION

The embodiment illustrated in Fig. 1, Fig. 2 and Fig. 3 constitutes the best mode for carrying out the invention. The embodiment includes two rotors 105 and two stators

101. The stators are fixed to the casing 1 1 1 and cannot move in any direction relative to the casing. Each stator has a coil of wire 102 with good electrical conductivity (copper for example). The wire is insulted as in the case of wire used in windings for motors or transformers. The stators each have a centre core 103 around which the coils are wound. A part of either stator passes between the poles of electromagnets 106 that are attached to the rotors as shown in Fig. 2 and Fig. 3.

The rotor shafts 109 sit in bearings 1 17, as shown in Fig. 3, which allow relative motion in the tangential ("Θ" or angular) direction but not in the axial or radial directions of the rotors, i.e. the rotors are free to rotate. Fig. 4 shows tangential ("Θ" or angular), radial R and axial Z directions, using Cylindrical Coordinates and X, Y, Z Cartesian Coordinates. Any force, such as F_τ , acting on a rotor tangentially or otherwise away from the centre of gravity of the rotor and at right angles to a line passing through the centre of gravity of the rotor will only cause rotation i.e. angular acceleration and hence an angular velocity.

Each electromagnet has coils of wire 107 wound around a core 108 of good magnetic permeability material (iron, for example). The higher the permeability of the core the better since less current is required to produce a magnetic field of particular strength.

The coils are energized via brushes 1 15 and segments of commutators 1 10 on either side of the rotor as shown in Fig. 2. The brushes are held in brush holders 1 14. Even though the embodiment shows rotors with only 4 electromagnets each, rotors may have more or less electromagnets. Fig. 5 shows a rotor 505 with 8 electromagnets. The electromagnets must always be arranged around the rotor in such a way that the rotor is balanced. Any imbalance would cause unwanted vibrations.

When current is passed through the stator coils and the windings of the electromagnets on the rotors that are closest to the stators, a force is experienced by the stators that is at right angles to both currents in the active sections of the stators and the magnetic fields between the poles of the electromagnets. The arrangement is such that the magnetic field B set up between the poles of the electromagnets is always at right angles to the current I in the sides of the stators that are actively involved in the process. See Fig. 6. The magnetic field acts over a length L of the stator coil. The poles of the electromagnet may be widened as in Fig. 14. The strength of the magnetic field remains practically the same. However, a wider area is covered thus effectively increasing the magnetic flux.

The currents in the stator coils are such that both stators experience forces in the same direction. Furthermore, as shown in Fig. 7, since there are two rotors and therefore two active electromagnets, each stator experiences two forces F_a in the same direction. Note also that since the currents on opposite sides of each stator are in opposite directions, one half of either stator is kept well away from the active electromagnet.

According to Newton's third law of motion, to every action there is an equal and opposite reaction. There must therefore be some forces which are acting in the opposite direction to those on the stators. In fact, the rotors experience these forces F_r that are acting in the opposite direction. The interaction between stator and rotor is such that the stators experience a force in one direction and the rotors in the opposite direction. The forces involved are illustrated in Fig. 7.

Since the stators are rigidly fixed to the casing 1 1 1 and base 1 12 via the stator supports 104 in all directions, any force acting on the stators will also be experienced by all the other parts of the device including the rotors themselves i.e. forces acting on the stators in any direction will be transmitted to the whole device. However, forces acting on the rotors can only be experienced by the rest of the device if the forces have components in the axial or radial directions of the rotors. Forces acting on the rotors in the tangential direction of the rotors, or otherwise away from the rotor centre of gravity at right angles to a line passing through the rotors^' centre (as the Force F_r in Fig. 7), are not transmitted to the rest of the device because of the bearings which allow freedom of movement. Such forces will only cause rotation of the rotors about their axial direction.

The only way action and reaction can cancel each other out is if they are both acting on such parts of the device and in such directions that they are both equally transmitted to all parts of the device. The arrangement of the invention is such that action and reaction are not equally transmitted.

The reaction force on the rotors acts in their tangential direction producing rotation of the rotors. Thus, the overall result is that all parts of the device, including the rotors, experience the force acting on the stators, that constitute the thrust T, but only the rotors experience the reaction force. Thus the whole device moves in response to the forces on the stators without any need either to push against or interact with any medium, surface or object external to itself or to eject mass. Holes 1 18 are provided for mounting to whatever needs to be driven.

The magnitude of the thrust T is dependent on the strength of the magnetic field B from the electromagnets, the number of turns n in the stator coils, the current i in the stators windings and the length L of the stator winding making contact with the magnetic field.

The effective current I flowing in the stator is a product of the number of turns and current in the stator windings. The strength of the magnetic field will itself in turn depend on the number of turns in the coils of the electromagnet and the current in those coils. The direction of the force may be reversed by reversing either the direction of the current in the stator coils or the direction of the magnetic field between the poles of the electromagnet.

Note that the rotors experience both the reaction force and the transmitted action force. See Fig. 8. Even though these forces appear to be in opposite directions, from the point of view of the rotors the forces are in fact orthogonal. The transmitted action force acts in a radial direction while the reaction force acts tangentially. The rotors respond to these forces by spinning about their own axis and simultaneously moving in a linear direction with the rest of the device.

As the rotors rotate the active electromagnets move and their commutator segments lose contact with the brushes. The next electromagnets are then activated and the whole process repeats. The greater the number of electromagnets around the rotors, the smoother the operation of the device. In order that the electromagnets on either rotor are activated and deactivated at the same time, the rotors should be synchronized. This may be achieved using gears, pulleys and belts, sprocket and chain or other such mechanism.

As illustrated in Fig. 7, the forces described above must act on both sides of the device for balance; otherwise the device would spin about its centre of gravity. Synchronizing gears 1 13 are used to synchronize the rotation of the rotors. A counter weight 1 16 may be used to ensure that the centre of gravity of the device lies along a centre line passing through the stators.

An alternative embodiment has rotors shaped as shown in Fig. 9 and Fig. 10. The magnetic field in this case is continuous and uniform with no gaps. There is only one electromagnet per rotor. The poles 230 of the electromagnet go right round the rotor in the form of a ring. Only one coil 207 is required per rotor. A continuous ring 210 replaces the segmented one for the power supply to the electromagnet. Only the core The shafts 209 going to the bearings are best made of a material of poor magnetic permeability.

When current is supplied to the stator coils and electromagnets of the alternative rotors, the forces generated are as in Fig. 1 1. All the forces may be reversed by reversing either the current in the stator coils or the magnetic field from the rotors. Note that the side forces, f_aiand f^, on the stators cancel each other out. The rotors each have an additional force f_r|_{, 2} which tends to make them rotate in the opposite direction to that of the original reaction force. However, the rotors are so positioned relative to the stators that only a small portion of the magnetic field from the rotors passes through the side of the stators. Thus the reaction force F_r is always greater than f_{H 2} The overall effect therefore, is as above, i.e. the rotors rotate and the whole device accelerates linearly.

It is also possible to have only a single rotor 405 and single stator 401. In this case a mass 424 has to be included on one side to ensure that the centre of gravity 425 falls along the line of action of the generated thrust. Fig. 12 illustrates the embodiment. Fig.

13 shows another alternative arrangement in which both sides of a stator 601 are used.

In this case, one set of rotors 605A interacts with only one side of the stator while the other set 605B with the other side of the stator. The magnetic fields of the electromagnets on the two sets of rotors are in opposite directions since the currents on the two sides of the stator are also in opposite directions. This ensures that the forces on the two sides of the stator are in the same direction.

Another alternative arrangement is shown in Fig. 15 and Fig.16. In this case the rotors 705 do not have electromagnets attached to them. Instead, pieces 730 of high magnetic permeability material are attached to the rotors. These have no windings on them. A set of electromagnets 706 attached to the base or casing of the device are used to induce magnetism into the pieces on the rotors. The stator is located between atleast a pair of said pieces at any one time.

A magnetic field is set up between the said pieces. A force is thus generated due to the interaction of the induced magnetic field and the current carrying conductors of the stator. Note that there is a small gap between the pieces on the rotor and the electromagnets so that the rotor is free to move relative to the electromagnets. When the rotor rotates, magnetism is induced in the next set of high permeability pieces. In this arrangement there are no brushes and segmented commutators. It also uses fewer electromagnets.

In all the embodiments described above, the electromagnet and stator coils maybe electrically connected in series, parallel or to completely separate power sources. The power source may be direct current (d.c) or alternating current (a.c). The wave form of the alternating current may be sinusoidal or take some other shape depending on the application. Transformers may also be employed to step-up or step-down the current (i.e. step-down or step-up the voltage) supplied to the coils as a way of manipulating the thrust generated by the rocket. Protection against over-current and over voltage may be included.

The thrust may be further controlled by appropriate feedback control schemes depending on the application. Electronics may also be used to control the voltages, currents or frequencies of the power supplied to the stator or electromagnets. Pulsed power may also be used to produce large currents in the stator and/or strong magnetic fields from the electromagnets in short bursts.

Coils made from a single wire with circular cross section will normally have spaces between wire segments. This makes the coil less compact. To reduce this effect multiple size wires or insulated strips with rectangular cross section may be used.

Due to the relative motion between the magnetic field on the rotors and the coils of the stators, a back electromotive force (emf) will be setup in the stator coils which opposes the stator current. This will tend to reduce the magnitude of the thrust generated by the device. This can be mitigated by controlling the speed of the rotors. This can be achieved by applying brakes, coupling the rotors to a load or a generator (which converts the rotational energy back to electrical).

A torque may also be applied on the rotors by, for example, an electric motor through a gear arrangement. The same methods may also be employed to simply prevent the

I O rotors developing excessive speeds. A flywheel may also be coupled to the rotors via sets of gears, pulleys or sprockets as a means of controlling the speed of the rotors. The rotor shaft may also be fitted with vanes over a section. The section can then be plunged in a high viscosity fluid to act as a damper.

As current flows in the electromagnet and stator coils, heat will be generated. A cooling system such as fans may be used to cool the windings. The casing may also have cooling fins 126 to increase the surface area for radiating heat. See Fig.1.

Superconductors may also be used to make the electromagnet and stator coils. Additionally, in all the arrangements mentioned above the electromagnets may be replaced by permanent magnets in which case no rings, commutators or brushes would be necessary. The cores of the electromagnets may or may not be laminated. The roles of the electromagnets and current carrying conductors may also be interchanged. The electromagnet could be fixed and the current carrying conductors free to move.

INDUSTRIAL APPLICABILITY

The invention may be used in a wide range of applications. Below are listed some possible applications.

1. As a drive for transportation vehicles: Cars have engines which could drive generators producing electricity. The electricity would then be supplied through appropriate electrical gear to Electromechanical Rockets. The Electromechanical Rockets would then push the vehicle horizontally. The cars may still have wheels but the drive would no longer be through the wheels (hence less chance of getting stuck in mud for example). The same would hold also for motorcycles. Boats and Ships could also be driven similarly. There would no longer be need to have a propeller sticking out into the water, hence reducing drag on the vessel.

When the thrust is directed upward, the Electromechanical Rocket provides an alternative for flight. Flying Vehicles based on the device would require neither runway nor wings. The aircraft would be able to take off and land vertically.

I l Aircraft with no wings would experience less drag. Furthermore, less landing and taking off space would be required. Like the helicopter, the aircraft would be able to land and take off anywhere. The aircraft would also be able to hover like the helicopter. Unlike the helicopter, however, landing and taking off would not be accompanied by the excessive disturbance of air and dust typical of helicopters.

The invention would also be an alternative to conventional rockets as far as space travel is concerned. The invention only depends on electricity, thus provided there is a source of electrical energy the device can work.

2. As a lifting device or as part of lifting equipment: Since the invention is easy to control by regulating the supplied current, it can safely be used as a lifting device both domestically and in industry. By controlling the current, the thrust can even be matched with the force of gravity so that the load can be held up in one position. The power source could be the mains, a generator or battery. Using the device in conjunction with a generator or battery makes it possible to utilise the invention in remote places.

A work platform that has the invention incorporated in it could be used to reach different heights when a person is working (for example when changing bulbs, painting, cleaning etc.)

3. Electromechanical Rockets could be used as linear drives for any other gadgets and applications where something needs to move or be supported. For any application, one or several Electromechanical Rockets may be used exerting forces in different directions to enable up/down, left/right, forward/backward or turning movements. LIST OF REFERENCE SIGNS

The main components of the Electromechanical Rocket illustrated in the drawings are:

101 Stator

102 Stator Coil

103 Stator Core

104 Stator Support

105 Rotor

106 Electromagnet

107 Coil of Electromagnet

108 Core of Electromagnet

109 Rotor Shaft

1 10 Commutator

1 1 1 Casing

1 12 Base

1 13 Synchronizing Gear

1 14 Brush Holder

1 15 Brush

1 16 Counterweight to balance Synchronizing Gears so that the Centre of

Gravity is at the centre of the device

1 17 Bearing for Rotor Shaft

1 18 Hole for Mounting Bolt

126 Cooling Fins

207 Coil of Ring Pole electromagnet

208 Centre Core for Ring Pole Electromagnet.

209 Shaft for Ring Pole Rotor (Shaft is non-ferromagnetic)

210 Ring Contact

230 Ring Magnetic Pole

401 Single Stator for the Single Rotor/Stator embodiment

405 Single Rotor for the Single Rotor/Stator embodiment

424 Counterweight to balance Rotor so that the Centre of Gravity falls at the centre of the device for the Single Rotor/Stator embodiment 425 Centre of Gravity for the Single Rotor/Stator embodiment

505 Rotor with eight electromagnets

601 Stator with Rotors on both sides

605 A Rotor on one side of double sided arrangement 605B Rotor on other side of double sided arrangement

705 Alternative rotor with pieces of high magnetic permeability attached

706 Fixed Electromagnet inducing magnetism on the rotor pieces

730 Pieces of high magnetic permeability. Magnetism is induced into the pieces by fixed Electromagnet (706).

Claims

CLAIMSHaving now particularly described and ascertained my said invention and in what manner the same is to be performed, I declare that what I claim is:

1. An electromechanical device that comprises one or more rotors with one or more electromagnets fixed to each of the rotors and one or more stators that have insulated conductors wound on them. The stators are rigidly fixed to the casing of the device. The rotors are free to rotate. Power is supplied to the electromagnets via brushes and segmented commutators. The magnetic fields of the activated electromagnets are at right angles to the current in the windings on the stators at one end. The stators experience forces that are at right angles to both the currents in the windings on the side of the stators that the forces act on and the applied magnetic fields from the electromagnets on the rotors. The magnitude of the forces depend on the magnitude of the currents in the stators, the number of turns in the stator windings, the strength of the magnetic field from the electromagnets and the length of the segment of the stator windings over which the magnetic field is applied. The rotors experience forces that are equal and opposite to those on the stators. Nevertheless, since the forces on the rotors act in a direction in which the rotors are free to move (or rotate), they are not transmitted to the rest of the device. The forces on the stators, however, are transmitted to the whole device including the rotors. The overall effect being that the whole device is made to move linearly by the forces on the stators without either the need to push against any external medium, surface or object or the need to eject mass. The device thus pushes or pulls any load attached to it.

2. An electromechanical device as in claim 1, wherein the stator coils and the electromagnets on the rotors are electrically connected to each other in series.

3. An electromechanical device as in claim 1, wherein the stator coils and electromagnets on the rotors are electrically connected to each other in parallel.

4. An electromechanical device as in claim 1 , which uses a direct current (d.c) power supply.

5. An electromechanical device as in claim 1 , which uses an alternating current (a.c) power supply.

6. An electromechanical device as in claim 2, which uses an alternating current (a.c) power supply.

7. An electromechanical device as in claim 6, in which transformers are used to step up the current (step down the voltage) or step down the current (step up the voltage) supplied to the device as a means of manipulating the overall thrust generated or speed attained by the device or the rotational speed attained by the rotors.

8. An electromechanical device as in claim 1 , wherein each rotor consists of a single continuous electromagnet with ring poles that go right round the rotor. Power is supplied to the electromagnet via rings that are not segmented.

9. An electromechanical device as in claim 1, wherein the electromagnets on the rotors are replaced with pieces of high magnetic permeability material without any windings. Magnetism is induced into the said pieces by electromagnets fixed directly or otherwise to the base or casing of the device. No brushes and commutators are used.

10. An electromechanical device as in claim 1 , wherein two sides of the stator(s) that are opposite each other are used to generate the thrust by placing a set of rotors on the said two sides.

11. An electromechanical device as in claim 1, wherein only a single rotor and a single stator are used with a balancing mass so that the centre of gravity lies on the line of action of the overall thrust.

12. An electromechanical device as in claim 1 , wherein the electromagnets on the rotors are replaced with permanent magnets.

13. An electromechanical device as in claim 8, wherein the electromagnets on the rotors are replaced with permanent magnets.

14. An electromechanical device as in claim 9, wherein the electromagnets that are fixed to the base or casing are replaced with permanent magnets.

15. An electromechanical device as in claim 10, wherein the electromagnets on the rotors are replaced with permanent magnets.

16. An electromechanical device as in claim 1 1 , wherein the electromagnets on the rotors are replaced with permanent magnets.

17. An electromechanical device as in claim 1, wherein a means of cooling the windings on the stators and the electromagnets on the rotors is incorporated.

18. An electromechanical device as in claim 1, in which a means of protecting the device against over-current is included.

19. An electromechanical device as in claim 1 , in which a means of protecting the device against over-voltage is included.

20. An electromechanical device as in claim 1, in which superconductors are used for the stator and/or electromagnet windings.

21. An electromechanical device as in claim 1, in which the cores of the electromagnets are made of iron.

22. An electromechanical device as in claim 1, in which the cores of the electromagnets are made of a material that has a magnetic permeability that is greater than that of iron.

23. An electromechanical device as in claim 1, in which the cores of the electromagnets are laminated.

24. An electromechanical device as in claim 8, in which the cores of the electromagnets are laminated.

25. An electromechanical device as in claim 9, in which the cores of the electromagnets are laminated.

26. An electromechanical device as in claim 1, in which the poles of the electromagnets are wider than the rest of the core.

27. An electromechanical device as in claim 1, wherein synchronizing gears, belts, sprockets or other means are used to synchronize the rotors so that the active electromagnets on the rotors are energized at the same time.

28. An electromechanical device as in claim 1, wherein the rotors are coupled to a load as a means of limiting the rotational speed of the rotors and hence the back emf generated in the device.

29. An electromechanical device as in claim 28, wherein the "load" is a flywheel coupled to the rotors via a set of gears, pulleys, sprockets and chains or other such means.

30. An electromechanical device as in claim 1 , in which a braking system is incorporated as a means of reducing the rotational speed of the rotors.

31. An electromechanical device as in claim 1, wherein an electric motor is used to aPply ^a torque on the rotors as a way of controlling the speed of the rotors.

32. An electromechanical device as in claim 1, wherein the rotors are coupled to a generator so that the rotational energy of the rotors is converted back into electrical energy.

33. An electromechanical device as in claim 1 , in which the current carrying conductors are on the rotors and the electro- or permanent magnets are on the stators.

34. An electromechanical device as in claim 1, wherein electronic or other means are employed to control the voltage, current or frequency of the power supplied to the device and hence the thrust generated or the speed attained by the device.

35. An electromechanical device as in claim 1 , in which electronic means are used to control the speed of the rotors.

36. An electromechanical device as in claim 1 , wherein feedback control is used to regulate the thrust generated by the device and/or the rotational speed of the rotors.

37. An electromechanical device as in claim 1 , in which currents with waveforms other than sinusoidal are supplied to the electromagnets on the rotors and/or the stator coils.

38. An electromechanical device as in claim 1 , wherein pulsed power is used to generated short bursts of large currents and or strong magnetic fields.

39. An electromechanical device as in claim 1 with a means of reversing the current flowing in the stator and/or electromagnet coils.

40. An electromechanical device as in claim 1 , wherein separate power supplies are used for the rotor electromagnets and stator coils.

41. An electromechanical device comprised of several units as in claim 1 bolted or otherwise assembled together.