1. Field of the Invention
The present invention relates generally to electric motors and alternators and more specifically to a modular motor or alternator assembly which is modular such that modules may be combined to increase power without the need to change or increase the size of the module.
2. Background Information
All around the United States and throughout the world, millions of people use electric motors and alternators on a daily basis. Conventional motors and alternators have a variety of configurations, but ordinarily have a cylindrical case. A stator having the general shape of a hollow cylinder fits inside the case and generally consists of series of windings of conducting wire (most often copper) in which layers of windings are often separated by insulating laminations. It is well known in the art that the method of winding stators determines whether the resulting current is single phase, two phase, three phase, or some multiphase. Ordinarily a rotor revolves on bearings in the ends of the case. The end portions of the case are ordinarily known as the end bells. The rotor may have windings or some other method of creating a permanent magnet or an electromagnet to create a magnetic flux around the rotor. Rotors historically may also include such well known devices as brush, commutator, or slip ring components necessary to the operation of an alternator or motor.
Conventional motors are usually measured using a horsepower rating. That is, a ten horsepower motor generally produces twice as much power as a five horsepower motor. Traditionally, a ten horsepower motor is physically larger than a five horsepower motor in all dimensions. That is, the rotors, stators, case, end bells, etc. are larger for a ten horsepower motor than for a five horsepower motor. This entails making a large variety of different components to create motors of different horsepower.
For a variety of well established reasons, standard electric power operates at a frequency of 50 or 60 Hz. Because of their necessary configurations, the fastest conventional alternators can run for generating conventional electric power is t 3,600 rpm at 60 Hz and 3,000 rpm for 50 Hz. If a device such as a modem turbine which may easily operate a speeds of around 50,000 rpm's is used to power such alternators, the speed must be mechanically reduced to either 3,600 rpm or 3,000 rpm to function properly. Furthermore, the operating speed of the turbine must be rigidly controlled for proper operation.
Furthermore, the flux in a rotor and in a stator create what amounts to a mechanical resistance which must be overcome in a conventional electric motor at start up. It is well known that such a motor requires up to 6 times running current to overcome this initial resistance.
Of course, it should be understood that alternators and motors have almost identical characteristics and most of the above applies to alternators as well as to motors.
The modular motor or alternator assembly of the instant invention solves a number of problems common to conventional motors and alternators. The rotor of the instant invention is solid and does not include windings, brushes, commutators, slip rings, or embedded magnets. A high speed drive device such as a turbine may be used without the necessity of using mechanical speed reduction. There is no startup current spike. Further the instant invention provides wide ranging torque and speed characteristics not known in the prior art without the need for a mechanical transmission. The modular motor or alternator assembly of the instant invention also provides solutions to many of the problems relating to the manufacture of motors and alternators of different sizes by providing a modular stator and coil unit which can be used to make motors of different power by simply adding more stator and coil units. For example, five, identical, one horsepower stator and coil units could be used to create a five horsepower motor.
The ideal modular motor or alternator assembly should operate with a rotor having no windings, brushes, commutators, slip rings, or embedded magnets. The ideal modular motor or alternator assembly (in its alternator aspect) should provide for the use of a high speed power source such as a turbine without the need for mechanical speed reduction. The ideal modular motor or alternator assembly should eliminate the startup power spike found in conventional electric motors. The ideal modular motor or alternator assembly should also provide wide ranging torque and speed characteristics not known in the prior art without the need for a mechanical transmission. The ideal modular motor or alternator assembly should also be created in a modular unit which may be used in multiple units to easily create motors or alternators having different power using the same module. The ideal modular motor or alternator assembly should also be simple, reliable, inexpensive, and easy to install and use.
The modular motor or alternator assembly of the instant invention may be operated as an alternator or as a motor. The physical configuration of the alternator and the motor is basically the same. A case is provided which has the general shape of a hollow cylinder and which has end bells with bearings at either end. The module case is made of a magnetic flux conducting material. A conventionally wound stator fits within the module case and is located at one end of the module case. The stator is wound for multiple phase operation. A field winding which is simply a coil of insulated copper wire in the preferred embodiment, is located at the other end of the module case. A solid steel rotor having a generally cylindrical shape rides on the bearings in the end bells. The rotor has a drive shaft which protrudes from one of the bearings in one of the end bells and a ride shaft which rides on the other bearing in the other end bell.
The rotor in the preferred embodiment has six lobes which run parallel to the longitudinal axis of the case, but more or fewer lobes could be used depending upon the desired configuration of the motor or alternator. These lobes are arrayed regularly around the circumference of the rotor. There is an air gap between the outer surface of the lobes of the rotor and the inner surface of the stator as well as between the outer surface of the lobes and the field winding. In the preferred embodiment of the instant invention, the air gap between the lobes and the field winding is greater than the air gap between the lobes and the stator.
A relatively small direct current is passed through the field winding. This has the effect of creating a north pole at one end and a south pole at the other end of the lobes of the rotor. By any of a number of conventional means, the current directed through the field coil may easily be controlled and, thus, the strength of the magnetic field induced in the lobes of the rotor may easily be controlled.
Several modules are created. There is a module for each of the end bells, a module which consists of a case portion having a stator and a field winding, and a module which consists of a case portion and a stator. The modules are manufactured such that the various modules may be fastened together securely with any number of modules hooked together. In the simplest form, the two end bell modules may be hooked together with a stator and field winding module, and a stator module to create a motor or alternator. Additional stator and field winding modules may be added, as desired, to, for instance, create a motor having greater power than a motor having a single stator and field winding module. In this manner various motors and alternators may be created using only single sized standardized parts or modules.
When the instant invention is being operated as an alternator, the drive shaft of the rotor may be connected to a prime mover such as a high speed turbine. The turbine turns the rotor at any efficient speed, such as 50,000 rpm. That is, the flux of the rotor may be reduced to nearly zero by having very little current in the field winding at startup. As with a conventional alternator, the rotation of the polarized lobes of the rotor induces an electric current in the windings of the two stators. The frequency of this current would be many times higher than the conventionally usable 60 Hz or 50 Hz.
In its motor configuration, the instant invention is the same as in the alternator description above except that the drive shaft powers any operating unit such as a wheel, gear or any other device which might be driven by an electric motor.
The above describes the basic operating principal of the modular motor or alternator assembly of the instant invention in one embodiment. There are a number of other embodiments and elements which are described in detail below.
One of the major objects of the present invention is to provide either an alternator or a motor which operates with a rotor having no windings, brushes, commutators, slip rings, or embedded magnets.
Another objective of the present invention to provide for the use of a high speed power source such as a turbine without the need for mechanical speed reduction.
Another objective of the present invention is to eliminate the startup power spike found in conventional electric motors.
Another objective of the present invention is to provide wide ranging torque and speed characteristics without the need for a mechanical transmission.
Another objective of the present invention is to provide a modular unit which may be used in multiple units to easily create motors or alternators having different power using the same module.
Another objective of the present invention is to provide a modular motor or alternator assembly which is simple, reliable, inexpensive, and easy to install and use.
These and other features of the invention will become apparent when taken in consideration with the following detailed description and the drawings.
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In operation, the alternator aspect and the motor aspect of the instant invention function is the same manner as conventional alternators and motors with the exception of said rotor 8 and said field winding 24. Rather than having permanent magnets or coils to create electromagnets, said lobes 18 of said rotor 8 are magnetized by passing a DC current through said field winding 24. The strength of the polarity of said lobes 18 is controlled by the amount of current passed through said field winding 24.
All elements of the modular motor or alternator assembly are made of steel, but other materials having similar strength, and magnetic properties could be used. Said field winding 24 is made with copper wire, but other conducting material could be used. While preferred embodiments of this invention have been shown and described above, it will be apparent to those skilled in the art that various modifications may be made in these embodiments without departing from the spirit of the present invention. That is, the device could be used for a wide variety of purposes either in combination or separately.