Electrical generator or motor structure – Dynamoelectric – Rotary
Reexamination Certificate
2001-06-25
2004-03-09
Dougherty, Thomas M. (Department: 2834)
Electrical generator or motor structure
Dynamoelectric
Rotary
C310S184000, C310S180000, C310S198000
Reexamination Certificate
active
06703747
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a generator having diverse power-generation characteristics, comprising a rotor of permanent magnets mounted on a rotator shaft supported in a stator frame for rotation, and a stator arranged around the rotor.
2. Description of the Prior Art
Modern advanced permanent magnets of high performance have become much employed on a rotor of a generator/motor. Moreover, as the generator/motor having the rotor structure of permanent magnets is high in efficiency of electromechanical energy conversion and simple in construction, its use has recently grown in industrial machines and instruments of various kinds. Then, much research and development have continued to make the generator/motor compact or slim in construction, with even high performance and high power output, and correspondingly necessitated a diversity of parts and components.
In order to increase a torque at low speed in the conventional generator/motors, it is effective to increase the strength of the magnetic field of the stator around the rotor, thereby raising the torque. With the generator/motors, thus, increasing well the torque causes the increase of electromotive force at a low speed, contributing to the provision of commercially viable power source for machines. Among the rotating machinery employing the permanent-magnet rotor is, for example a permanent-magnet rotating machine disclosed in Japanese Patent Laid-Open No. 272850/1987. The prior permanent-magnet rotating machine has a rotor in which permanent magnets are arranged and containers are provided to contain therein magnetic material that is allowed to flow radially owing to the revolution of the rotor to thereby form magnetic pole pieces.
Moreover, another prior art of an a-c generator/motor developing a high-power output is disclosed in Japanese Patent Laid-Open No. 236260/1995, in which a magnetic flux density is controlled in proportion to the rpm of the rotor to adjust properly an amount of the generated amperes or voltages. A control ring is arranged between the rotor and the stator for rotation relatively of them and further a permeable member is provided in such a manner as to come in and out contact with the control ring.
In the meantime, as most automotive electric equipments are designed to require either 12V or 24V, the automotive alternators need to have the generation characteristic capable of feeding the electric power matching to the voltage recited just above. Nevertheless, the d-c power of either 12V or 24V is too low to operate the machinery and instruments mounted on an automobile, in which much power is required for their operation. The low tension is apt to be much subject to transmission loss in the associated wiring. Moreover, a major problem exists in which too thick in cross section of conductor is necessitated for the winding. To cope with this, the alternator is needed producing not only the electric power of low voltage matching to the voltage required for the automotive electric equipments but also another electric power having high tension of about 100V or 200V and so on, which is enough to reduce the transmission loss in the wiring and render the conductor such as winding thin in cross section, thereby making it possible to drive the auxiliaries constructed compact or slim.
With the permanent-magnet generator/motor, the permanent magnet is fixed in magnetic flux density. Thus, the increase of the torque at a low speed needs to either make the permanent magnet large in size or increase the current and also increase the number of loops or turns in the winding to intensify the strength of the magnetic field at the stator side. To realize much torque, it is necessary to make the conductor wound on the stator core heavy in cross section and also the number of turns large to carry much current, thereby increasing the magnetic force of the stator. Nevertheless, too heavy in cross section of the winding conductor laid in a slot of the stator core makes it tough to lead the conductor through the slot between any adjacent teeth in the stator core and embed the windings in the slot of the stator core. In addition, since most the stator core are constructed in such a configuration that the slots are open radially inwardly while the outer periphery is closed with a cylindrical magnetic path, it is much hard to lead the windings through the slot from the inside hollow space in the stator core and wind them on the associated teeth, for the sake of which there has been some tendency to reduce the occupancy of the conductors in the associated slot.
In order to cope with the major consideration stated just earlier on the fabrication of the stator of the generator/motor, there has been conventionally proposed a production method in which teeth of the toothed member for the stator are first laid in juxtaposition and then the winding turns are wound in the slot. Thereafter, the toothed members are assembled into the complete cylindrical configuration. However, yet another problem with the production method recited earlier is to require additional fabricating operation: separating the stator core into many teeth or notching the stator core each tooth.
In the normal electric rotating machines, the windings to produce sinusoidal waveforms are wound spanning some teeth of the stator with either a concentrated-winding or a distributed-winding technique. Nevertheless, the production method recited earlier in which the toothed members are laid side by side is unsuitable for the distributed-wound field winding rather than the concentrated-field winding because the winding loops are not allowed to overlap with each other at the junctions between the adjacent toothed members.
SUMMARY OF THE INVENTION
It is a primary object of the present invention to overcome the problems stated earlier and to provide a generator having diverse power-generation characteristics, in which more than one windings either distributed-wound or concentrated-wound in slots between any adjacent teeth are connected in parallel and/or in series, with changed in combination to ensure powers different in voltage from one another, each of which may be applied across any loads requiring different voltages, for example automotive electric equipments of 12V~24V and auxiliaries such as heaters, largemotors and so on of 100V~200V. Moreover, an object of the present invention is to provide a generator having diverse power-generation characteristics, in which a stator core is formed in a cylindrical configuration with teeth being arranged around the outer periphery of the stator core in a manner extending radially outwardly to provide slots opened radially outwardly, while windings are laid in the slots with either concentrated-winding or distributed-winding to mount the winding on the radially outwardly extended teeth, and a cylindrical magnetic path fits over the radially outwardly extended teeth, on which the windings have been wound, thereby making it possible to manufacture the stator with ease.
The present invention is concerned with a generator with diverse power-generation characteristics, comprising a rotor shaft supported for rotation in a stator frame, a rotor mounted against rotation on the rotor shaft, and a stator arranged around the rotor and fixed to the stator frame, wherein the stator is comprised of an inside cylinder arranged around the rotor to define an air gap between confronting surfaces of them, teeth arranged spaced circumferentially on the inside cylinder to form sequential slots, an outside cylinder surrounding around tooth tips of the teeth, more than one systems of stator windings either concentrated-wound or distributed-wound with a preselected slot span, one of which is low power windings each containing a small number of turns while another of which is high power windings each containing a large number of turns, and terminal lines having terminals connected to any preselected low power and high power windings.
In an aspect of the present invention, a generator is disclosed, wh
Browdy and Neimark , P.L.L.C.
Dougherty Thomas M.
Pham Leda
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