Electrical generator or motor structure – Dynamoelectric – Rotary
Reexamination Certificate
1999-04-30
2001-06-19
Tamai, Karl (Department: 2834)
Electrical generator or motor structure
Dynamoelectric
Rotary
C254S050100, C254S254000
Reexamination Certificate
active
06249071
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention concerns an improvement to the rotor drive motor described in the parent application referenced above.
That application describes a rotor drive motor featuring permanently magnetized fan blades on the rotor which interact with the magnetic fields generated by stator coils arranged at each corner of an enclosing housing.
This greatly reduces the bulk of the fan hub by eliminating the conventional fan motor located at the fan hub, increasing the space available for air flow to substantially improve the performance and efficiency of the fan, particularly useful for installations in constrained spaces.
The fan blades are permanently magnetized in a radial orientation, with each successive blade having magnetic poles oppositely oriented relative to the poles of the adjacent magnetized fan blades. The polarity of the magnetic fields generated by the stator coils are successively reversed by reversing the current applied thereto as each fan blade passes each stator.
By this arrangement, the rotor drive motor stators are thereby located outside the air flow space.
The efficiency of this arrangement depends on the interaction between the stator magnetic field and the magnetic field of the permanently magnetized fan blades.
It is an object of the present invention to improve the output of this rotor drive motor by increasing the torque generated by the interaction of the stator coil and blade magnetic fields.
Another advantage of the improved rotor drive motor using exterior stator coils and magnetized fan blades is that the air flow does not pass through, past, or over the electrical components of the motor and controls.
It is another object of the present invention to provide a fan motor housing arrangement which isolates the air flow from any contact with the electrical components to render the fan suitable for use in an explosive or contaminated atmosphere.
SUMMARY OF THE INVENTION
These and other objects of the present invention which will be understood upon a reading of the following specification and claims are achieved by configuring the core of each stator in a U-shape, with the legs of the core each directed radially inwardly and abutting against the housing shroud. This core configuration has been found to increase the stator coil magnetic field flux density in the radial direction, and to thereby maximize the drive torque generated by the interaction of the stator coil and blade magnetic field. This, in turn increases the power output of the rotor drive motor and the fluid flow volume generated by rotation of the blades for a given electrical voltage applied to the stator coil windings.
The rotor drive preferably consists of only two stator coils, which are alternatively energized periodically in synchronism with the rotation of the magnetized rotor blades, which are permanently magnetized so as to be of successively opposite polarity.
A pair of sensors are positioned so as to be triggered as each blade sweeps past a detection location associated with each sensor, and power control circuitry causes each stator coil to be briefly energized by an electrical current of the proper polarity to cause a magnetic field to be generated interacting with each fan blade to drive the fan rotor in a given direction.
In a second aspect of the present invention, the blade shroud is sealed to fluid flow passage conduits thereby isolating the electrical components which are disposed externally of the shroud from the air flow.
REFERENCES:
patent: 4367413 (1983-01-01), Nair
patent: 4553075 (1985-11-01), Brown et al.
patent: 5290227 (1994-03-01), Pasque
patent: 5474429 (1995-12-01), Heidelberg et al.
patent: 5607329 (1997-03-01), Cho et al.
patent: 5616974 (1997-04-01), Yamada
patent: 5695471 (1997-12-01), Wampler
patent: 61-052181 (1986-03-01), None
patent: 58-066553 (1986-03-01), None
Lopatinsky Edward L.
Rosenfield Saveliy T.
Advanced Rotary Systems LLC
Dreyfus Edward
Tamai Karl
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