Did You Know...
...that power steering was invented by independent inventor Francis W. Davis? As chief engineer in the 1920s of the truck division of the Pierce Arrow Motor Car Company, he saw how hard it was to steer heavy vehicles. So that he would be able to keep the profits from his future invention, Davis left his job, rented a small engineering shop in Waltham, Mass., and developed a hydraulic power steering system that led to power steering.
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| Number | Title | Issue Date |
| 7898224 | Method for switching low-power using AC and system for performing the same and power supply for using the system A power control method using AC power, the method being capable of performing: low power control that passes only two portions of positive direction waves of each one-cycle sine wave of the AC power and only two portions of negative direction waves of each one-cycle... | 03/01/2011 |
| 7321834 | Method for calculating power flow solution of a power transmission network that includes interline power flow controller (IPFC) Power flow models of Interline Power Flow Controllers (IPFC) for large-scale power systems are studied, in details. Mathematical models of the IPFC, using the d-q axis decompositions of control parameters are derived. In this framework, for each IPFC, only two contr... | 01/22/2008 |
| 7294971 | Balancing transformers for ring balancer A ring balancer comprising a plurality of balancing transformers facilitates current sharing in a multi-lamp backlight system. The balancing transformers have respective primary windings separately coupled in series with designated lamps and have respective secondar... | 11/13/2007 |
| 7294976 | Split power supply subsystem with isolated voltage supplies to satisfy a predetermined power limit A power subsystem including a mechanism for satisfying a predetermined power limit in a computer system. The power subsystem may include a split power supply and a voltage regulator. The split power supply may include at least a first voltage supply line and a secon... | 11/13/2007 |
| 7049921 | Auto-transformer for use with multiple pulse rectifiers Zig-zag connected, phase shifting, auto-transformers that provides the inherent ability to block the flow of zero sequence currents that are associated with multiple-pulse rectifiers. The transformer coils are wound in three separate, multi-wound windings on three s... | 05/23/2006 |
| 7019467 | Thermally-protected ballast for high-intensity-discharge lamps A ballast for electrical lighting fixtures with improved thermal protection features has ballast laminations, primary and secondary coils, and a thermal protector, the thermal protector being wired in series with the secondary coil. The ballast preferably is of the ... | 03/28/2006 |
| 6997935 | Resonant converter tuning for maintaining substantially constant phaco handpiece power under increased load A phacoemulsification system includes a phacoemulsification handpiece including a cutting tip ultrasonically vibrated by an ultrasonic transducer. A power supply is provided for driving the ultrasonic transducer at a resonant frequency of the transducer and cutting ... | 02/14/2006 |
| 6995993 | Rectification system for improving power quality of electrical power systems A system and method for an autotransformer configuration including a plurality of windings which can be used to provide a substantial reduction in harmonics. The autotransformer includes a series of wye windings configured to provide a constant length voltage vector... | 02/07/2006 |
| 6992872 | Circuit breaker incorporating fault lockout protection A method of protecting multiple feeder circuits fed from a shared electrical distribution system is provided. The method includes providing a bypass line, providing bypass switches in the bypass line, providing a fault lockout protection controller coupled to the by... | 01/31/2006 |
| 6958579 | Thermally-protected ballast for high-intensity-discharge lamps A ballast for electrical lighting fixtures has improved thermal protection features. The ballast has ballast laminations, primary and secondary coils, and a thermal protector, the thermal protector being wired in series with the secondary coil. When the ballast is o... | 10/25/2005 |
| 6924627 | Method of reactive power regulation and aparatus for producing electrical energy in an electrical network A method of reactive power regulation in an electrical network in which electrical power is produced by an electrical generator preferably driven by the rotor of a wind power installation and suitably modulated by means of a compensation device between the generator... | 08/02/2005 |
| 6924608 | System and method for ignition and reignition of unstable electrical discharges Systems and methods for ignition and reignition of unstable electrical discharges wherein a secondary electrode positioned is between a set of primary electrodes and a high voltage is applied between the secondary electrode and successive ones of the primary electro... | 08/02/2005 |
| 6806688 | Difference power adjustment apparatus having a capacitor and reactor connected power-system bus A power adjustment apparatus includes a phase shifter including a stator having a stator winding and a rotor having a rotor winding, a winding terminal of one of the stator winding and the rotor winding being connected to a power-system bus, and a winding terminal o... | 10/19/2004 |
| 6523654 | Reducing inrush current when transformer in electric vehicle is connected to power A method of controlling connection of a transformer of an electric vehicle, such as a train locomotive, to an alternating voltage supply carried by a trolley wire, the object being to reduce the transformer inrush current on connection of the transformer ... | 02/25/2003 |
| 6396248 | Versatile power flow transformers for compensating power flow in a transmission line A power flow transformer implements power flow control in a transmission line of an n-phase power transmission system, where each phase of the power transmission system has a transmission voltage. The transformer has n secondary windings, where each secon... | 05/28/2002 |
| 6300747 | Circuit having reduced losses occurring during transforming switching adjusting or controlling electric power The invention relates to a circuit for transforming, switching, adjusting or controlling electric power, comprising an electric source 1, a load 2, and a device 3 for transforming, switching, adjusting or controlling the electric power resulting on the lo... | 10/09/2001 |
| 6166494 | Drive circuit arrangement for a gas discharge lamp A drive circuit arrangement for a gas discharge lamp includes a) a self resonating inverting for providing a drive voltage across a load impedance, the inverter having a pair of field effect transistors which operate in anti-phase, b) a tank circuit for c... | 12/26/2000 |
| 6011381 | Three-phase auto transformer with two tap changers for ratio and phase-angle control Autotransformer design which is capable of modifying the active power flow in autotransformers connecting two different voltage systems in an electrical substation. The bus-tie autotransformers presented change the active power flow by modifying the phase... | 01/04/2000 |
| 5969510 | Three-phase to six-phase wye transformer power system The present invention discloses a method for providing balanced power to a single-phase ac load from a three-phase ac power source. The method includes imposing an isolation power transformer between the ac power source and the load wherein the isolation ... | 10/19/1999 |
| 5952816 | Compensation for power transfer systems using variable rotary transformer In an interconnection system (100) for transferring power between a first grid (22) operating at a first electrical frequency and voltage and a second grid (24) operating at a second electrical frequency and voltage, compensation circuits including a shun... | 09/14/1999 |
| 5914540 | Filter for removing harmonic current from a neutral conductor A neutral conductor filter having three transformers. A first transformer has a primary winding connected to a first power conductor and the neutral conductor. A second transformer has a primary winding connected to a second power conductor and the neutra... | 06/22/1999 |
| 5841267 | Power flow control with rotary transformers A power flow controller seeks to inject a voltage Vser on a transmission path between a first electrical area and a second electrical area, in order to cause a desired power flow into the second electrical area. The power flow controller (20) i... | 11/24/1998 |
| 5818126 | Power transfer controller A method and apparatus for controlling power transferred and regulating voltage in a multi-phase transmission line includes generating a first plurality of voltages, a second plurality of voltages displaced in phase from the first plurality of voltages, a... | 10/06/1998 |
| 5796631 | Method and apparatus for monitoring and characterizing power quality, faults and other phenomena in network power systems A method and apparatus for receiving, monitoring and characterizing network power information in real time through the use of a specialized display system. A processor receives three phase current and voltage information from a network power relay, conver... | 08/18/1998 |
| 5719489 | Apparatus for determining load currents A compact power circuit configured for circuit breaker applications includes, in one embodiment, a plurality of current transformers, each current transformer being coupled to a respective one of the phase lines of a power line to generate a current propo... | 02/17/1998 |
| 5698969 | Apparatus and method for interline power flow control An apparatus and method are disclosed for controlling the power flow in an electric transmission system including at least two transmission lines, each transmission line having two ends and carrying alternating current at a selected transmission line volt... | 12/16/1997 |
| 5625277 | Dynamic mechanically switched damping system and method for damping power oscillations using the same A dynamic mechanically-switched damping (DMSD) system is described which utilizes one or more mechanical switches and appropriate controls to switch series or shunt reactive impedances in order to provide power oscillation damping in power systems. The DM... | 04/29/1997 |
| 5619119 | Method of phase-shifting voltages applied to susceptances interconnecting two synchronous polyphase AC networks and a phase-shifting interconnecting apparatus thereof A phase-shifting interconnection apparatus for interconnecting respective phase lines of first and second synchronous polyphase AC networks, includes for each pair of respective phase lines subjected to an interconnection a pair of circuit branches in par... | 04/08/1997 |
| 5576942 | Method and apparatus for reducing the harmonic currents in alternating-current distribution networks An improved apparatus and method reduce the harmonic content of AC line and neutral line currents in polyphase AC source distribution networks. The apparatus and method employ a polyphase Zig-Zag transformer connected between the AC source distribution ne... | 11/19/1996 |
| 5537309 | Multi-phase and shifted phase power distribution systems A method and apparatus for providing a source of alternating current electrical power to a plurality of loads in an office environment, including a plurality of non-linear loads which draw power for only a portion of the alternating current cycle, include... | 07/16/1996 |
| 5469044 | Transmission line power flow controller with unequal advancement and retardation of transmission angle A bias voltage vectorially added to the controllable voltage injected in series with the line voltage of a transmission line reduces the required MVA rating for a unified power flow controller (UPFC) in applications where the power in the transmission lin... | 11/21/1995 |
| 5461300 | Phase angle regulating transformer with a single core per phase A dynamic phase angle regulator for enhancing the transient stability of a three phase AC power system includes a controller, a switching assembly of thyristor switches, and a single transformer coupled to a power line. The transformer includes a balanced... | 10/24/1995 |
| 5166597 | Phase-shifting transformer system A faster, more controllable phase-shifting transformer system is provided, along with a method of retrofitting and upgrading a preexisting system for faster operation, and a method of applying a desired phase shift to the voltage on a polyphase transmissi... | 11/24/1992 |
| 5164614 | Low power bias voltage generating circuit comprising a current mirror A bias voltahe generating circuit which is low in power consumption and small in chip size of an IC and does not pickup noises readily. The bias voltage generating circuit comprises a current mirror circuit including a diode-connected first transistor of ... | 11/17/1992 |
| 5107410 | Multi-phase and shifted phase power distribution systems A method and apparatus for providing a source of alternating current electrical power to a plurality of loads in an office environment, including a plurality of non-linear loads which draw power for only a portion of the alternating current cycle, include... | 04/21/1992 |
| 5013997 | Liquid cooled, high power, ferrite phase shifter for phased array antennas A compact, liquid cooled, ferrite phase shifter is capable of handling high power microwave signals without thermally stressing the ferrite core. The ferrite core is mounted on spacers inside of a hermetically sealed wave guide filled with a thermally con... | 05/07/1991 |
| 4893069 | Ferroresonant three-phase constant AC voltage transformer arrangement with compensation for unbalanced loads A ferroresonant three-phase constant AC voltage transformer comprising three transformer iron cores with one for each corresponding input supply phase, primary windings and secondary windings formed on each of the transformer iron cores, series reactance ... | 01/09/1990 |
| 4862059 | Ferroresonant constant AC voltage transformer Primary and secondary windings of each transformer in a three-phase system each form a pair of independent windings, the first winding of each of the primary and secondary pairs formed on the iron core of one of the transformers and the second winding of ... | 08/29/1989 |
| 4700123 | Power distribution systems and means for control thereof In a power distribution system, power line insulators have three electrodes, two of which are connected to the line and to ground, and the third of which forms a capacitively stepped down voltage corresponding to the line voltage, and use sensing coils to... | 10/13/1987 |
| 4665322 | Uninterruptible polyphase AC power supply An uninterruptible polyphase AC power supply equalizes an electric power taken out from a polyphase AC power source, even if unbalanced load is connected to output. The uninterruptible AC power supply comprizes a polyphase balanced phase shifter generatin... | 05/12/1987 |
