Electrical generator or motor structure – Dynamoelectric – Rotary
Reexamination Certificate
2003-09-27
2004-11-23
Mullins, Burton (Department: 2834)
Electrical generator or motor structure
Dynamoelectric
Rotary
C310S114000
Reexamination Certificate
active
06822361
ABSTRACT:
FIELD OF THE INVENTION
This invention relates generally to the field of direct current electrical motors and generators that operate without the need for commutation and/or rectification, and more particularly to multi-rotor homopolar machines which derive their emf (electromotive force) from co-rotational magnets and metallic disk embodiment.
BACKGROUND
Back in 1831, Michael Faraday discovered that a cylindrical magnet suspended by a string and touching a mercury bath at the bottom could generate electricity while spinning along its axis if a second electrical contact was made at the periphery of the midpoint of the magnet. His experiment was a one-piece homopolar machine since the magnet and conductor were joined together. Such Faraday generators have also been called acyclic, unipolar or homopolar generators because no commutation or alternating of the magnetic poles is necessary for this machine in order to generate electricity.
The type of electrical output is most often direct current (DC) unless specific means are designed to provide an interruption of radial conduction and thus simulate alternating current (AC). Historically, DC was championed by Thomas Edison during the early part of the 20th century while at the same time AC was championed by Nikola Tesla and George Westinghouse. In the future, DC will be coming back into style with the emergence of ambient temperature superconductive cables. Therefore, highly efficient homopolar generators will be in demand to meet the future market demand for DC electricity.
Homopolar generators usually have a single disk or drum rotating in a stationary magnetic field with sliding contacts. The sliding contacts often present high resistance however. The construction and operation of homopolar machines for electric propulsion of marine vessels or railguns for example is already well known. Such machines include motors and generators wherein electrical current flows through a conductor situated in a magnetic field during rotation of the machine rotor.
In the case of a homopolar motor, the current will develop a J×B force perpendicular to the direction of its flow through the conductor and that of the magnetic field. In the case of a homopolar generator, a voltage dependent on the rotational speed, magnetic field, and radius, is induced in a conductor moving within the magnetic field. When current is drawn from the homopolar generator, it also develops a J×B force for the same reason as with the motor but is referred to as back torque or armature reaction. General reference information including basic principles used to reduce back torque can be found in
The Homopolar Handbook
by Thomas Valone (ISBN 0-9641070-1-5).
The prior art rarely includes a one-piece homopolar machines that rotate the magnet with the disk. Even more unknown is the concept of rolling contacts. Eliminating sliding contacts is shown in the “Planetary Homopolar Generator,”
IBM Technical Disklosure Bulletin
, Vol. 17, No. 6, p. 1786-87, November, 1974, H. D. Varadarajan.
Using a conducting belt or rolling contacts to gather current from a magnetic field flux cutting rotor, there is an annular magnetic field through which the rotor executes a planetary motion.
The large stresses resulting from the centrifugal force of the massive, unbalanced planetary rotor is a distinct disadvantage, prohibiting high speed operation. Thus, only a low rate of rotation is possible with the IBM design.
The “Direct Current Homopolar Machine” U.S. Pat. No. 5,587,618 to Hathaway demonstrates an analogous concept of relative motion between conductive orbiting shaft and a stationary disk-shaped magnetized armature.
However, the design is a bit cumbersome to be practical. Science Applications International Corporation claims a conductive belt, dual disk “Homopolar Motor-Generator” in U.S. Pat. No. 5,241,232 to Reed that apparently reinvents the “Dynamo Electric Machine” of U.S. Pat. No. 406,968 patented by none other than Nikola Tesla in 1889 that also has two unipolar magnetized rotors connected by a conductive belt. The belted dual unipolar machines solve one of the problems that plague the field by offering two sliding contacts at the low speed surface on the axle. However, the present invention requires only one sliding contact on the axle. These conductive belt machines also demonstrate, in principle, the concept of a multi-rotor, planetary design, by the process of coordinate transformation, since relative motion is the key to the operation of a homopolar generator. The concept of rolling contact is demonstrated with the Dalen “Dynamo Electric Machine” U.S. Pat. No. 645,943, where two disks are turning in opposite directions while in contact with each other at their periphery. However, the axle of each disk must remain fixed in place whereas each axle is in orbiting motion in the present invention.
Homopolar machines can reversibly function as motors as well, such as flywheels, and used as energy storage devices. First used in transportation applications in the 1950's, flywheel powered buses were designed to have the flywheel accelerated at every stop. Composite rotors currently have been developed which can spin at very high revolutions (100,000 revolutions per second); and the speed is limited by the tensile strength of the rim of the rotor. By using a multi-rotor design, the centrifugal forces of a large disk can be greatly reduced and still maintain high-energy storage or production. By using magnetic bearings, the friction on the axis of the rotor can be reduced sufficiently so that such rotors can maintain most of the energy for several days.
The IBM Varadarajan planetary rotor is unbalanced and has a low rate of magnetic flux cutting due to its annular magnetic field design. The Hathaway direct current machine has a lot of unbalanced conductive material orbiting the central magnetized disk which limits the rotational speed.
The conductive belt designs can be subject to oxidation and slippage, even requiring a toothed timing belt on each axle as well. With most disk models of homopolar generators, as opposed to drum designs, sliding contacts are the single most important contribution of resistance inhibiting the power output of the machine. Internal resistance is the only limit to the output capability of a homopolar generator and it is important to reduce all sources of internal resistance to obtain maximum power output for a given input torque. Rather than use high resistance carbon brushes, medium resistance silver-graphite brushes or dangerous conductive liquids such as mercury, low temperature solder, or sodium-potassium, there is a need to eliminate frictional sliding contact at the high speed periphery of the magnetized rotor completely. Furthermore, rather than maintaining two sliding contacts which contribute friction and resistance, even in the rolling and belted designs, there is a need to cut the number in half to only one high current sliding contact. The present invention satisfies both of these needs.
SUMMARY
The present invention derives direct current electricity by co-rotating a plurality of magnets and a metallic disk. It comprises an improved homopolar machine with dynamically balancing, axially parallel, cylindrical, electrically conductive magnets arranged circumferentially around the vertical axis of central stator ring. Such a design can be referred to as distributed generation since each magnet rotor generates only a fraction of the current that is transmitted through the machine. Thus, the conductive bearings contacting the center of each end of the magnet rotors may carry only one tenth or less of the total current.
The multi-rotor orbiting homopolar also does not include sliding contacts at each magnetized rotor rim but instead utilizes a suitable rolling means attached separately to magnets and also to the stator ring for intimately contacting and engaging non-slip rolling between magnets and stator as they orbit around the stator. The magnetized rotors maintain rotational synchronism and equal relative position to each other with
Godin Sergi Mikhailovich
Roschin Vladimir Vitalievich
Energy & Propulsion Systems LLC
Mullins Burton
Our Pal LLC
LandOfFree
Orbiting multi-rotor homopolar system does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Orbiting multi-rotor homopolar system, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Orbiting multi-rotor homopolar system will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3343091