| Title |
Primary Class |
Description |
Inventor |
Assignee |
Issue Date |
Patent No. |
| Method of operating arc lamps |
315/246 |
An alternator that produced, what at that time was, radio high-frequency current of around 10,000 hertz. Tesla suppressed the disagreeable sound of power-frequency harmonics produced by arc lamps operating on frequencies within the range of human hearing. The produced pulsations were in the longwave broadcasting range (LF) and very low frequency band (VLF). |
Nikola Tesla |
___ |
March 10, 1891 |
US447,920 |
| Alternating electric current generator |
310/168 |
An alternator that produced 15KHz by employing a great number of poles or polar projections. The first efficient and practical electromechanical generator. A field-magnet core made up of two independent parts formed with grooves for the reception of one or more energizing coils. The energizing coils are completely surrounded by the iron core, except on one side, where there is a narrow opening between the polar faces of the core, and the polar faces of the core are formed with many projections or serrations. This field-magnet design produced less magnetic leakage but still did not operate at a desired level of efficiency. |
Nikola Tesla |
___ |
March 10, 1891 |
US447,921 |
| High frequency alternator |
310/169 |
The Alexanderson mechanical alternator: a high-frequency generator, up to 100 kHz, for longwave transmissions, which made modulated (voice) radio broadcasts practical. |
Ernst F. W. Alexanderson |
General Electric Company, New York |
November 14, 1911 |
US1,008,577 |
| Sine wave generator |
307/106 |
Sine-function generator |
Otto J. M. Smith |
Hewlett-Packard Company (HP) |
May 29, 1956 |
US2,748,278 |
| Constant-Frequency Alternating-Current Generators |
322/32 |
Means responsive both to the actual rotor speed and to a reference frequency energizes the stator winding of the main generator for producing an exciting field having a rotational speed equal to the difference between the ideal speed and the actual speed of the main generator rotor. |
Wilfried Lewis Turvey |
Sperry Gyroscope Company |
April 1, 1958 |
US2,829,333 |
| Biased unitized motor alternator with stationary armature and field |
318/140 |
A unitized (single unit) motor and flux switch alternator having stationary field, armature and motor windings which provides a magnetic path for some of the motor input power to feed through and increase the alternating current (AC) generator output. A rotor formed from a material having a high magnetic permeability (solid or laminated soft steel) is controlled in speed by controlling the magnitude and timing of the pulsed direct current (DC) supplied to the motor windings which may be wound on the stationary legs or the rotor. The current flow in the motor windings can be controlled by a mechanical commutator if the motor windings are on the rotor or by a solid-state converter if the motor windings are on the legs in a manner normally associated with brushless DC motors. The DC windings of the flux switch alternator can be replaced by permanent magnets since the reversing field in the AC output windings are predominantly time stationary. |
John W. Ecklin |
___ |
January 28, 1986 |
US4,567,407 |
| Boost converter regulated alternator |
363/89 |
A circuit that involves the application of boost mode regulator techniques is used to regulate the output of an a.c. source. The source inductance becomes part of the boost mode circuit, thus avoiding the losses associated with the addition of external inductors. When a three-phase alternator is the power source, the circuit comprises a six diode, three-phase rectifier bridge, three FET transistors and a decoupling capacitor. The invention involves shorting the output of the power source to allow storage of energy within the source inductance. During this time, the decoupling capacitor supports the load. When the short is removed, the energy stored in the inductances is delivered to the load. Because the circuit uses the integral magnetics of the source to provide the step-up function, the efficiency of the design can be quite high. |
W. Thomas Balogh |
Baker Hughes Incorporated |
August 11, 1998 |
US5,793,625 |
