Did You Know...
...that in 1800 ether was first used by partyers as a fun diversion? Sniffing the gas led to hilarious and raucous laughter as people watched each other become more and more intoxicated and silly. Several doctors independently realized the value ether would have to anesthetize surgery patients. Of those who claimed rights to the "discovery," none had a happy ending. One had a seizure and died defending his rights. Another spent his life in an asylum because he had been denied acclaim. A third became addicted to chloroform and, in a New York City jail, he soaked a cloth in the drug, severed an artery and bled to death.
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| Number | Title | Issue Date |
| 8169181 | Induction motor An active reactive induction motor is provided. The motor comprises two sets of three-phase windings. One set of windings carries the active power and is called the power windings. The second set of windings carries the reactive power and is called the flux windings... | 05/01/2012 |
| 7408323 | Frequency converter, motor, motor drive system and maintenance method for motor drive system A frequency converter for outputting a power to drive a motor, having: an inverter unit for inverting a d.c. power to an a.c. power; a control unit for controlling the inverter unit; and a housing for supporting at least the inverter unit and control unit, wherein a... | 08/05/2008 |
| 7262577 | Method for estimating the sum of stator and rotor resistances A method for estimating the sum of the stator and rotor resistances of an induction machine using a frequency converter when the frequency converter is connected to the induction machine. The method comprises the steps of controlling the stator current of the induct... | 08/28/2007 |
| 7202628 | Frequency converter, motor, motor drive system and maintenance method for motor drive system A frequency converter for outputting a power to drive a motor, having: an inverter unit for inverting a d.c. power to an a.c. power; a control unit for controlling the inverter unit; and a housing for supporting at least the inverter unit and control unit, wherein a... | 04/10/2007 |
| 7170245 | Motor power supply control apparatus A motor power supply including a DC supply part having a pair of supply terminals; an inverter having a pair of connection terminals respectively connected to the supply terminals thereof to receive DC power therefrom and to supply AC power to a motor, a breaking re... | 01/30/2007 |
| 7095209 | Method and apparatus to regulate torque provided to loads A method and apparatus for use with a controller for controlling a machine wherein a torque reference value is provided, the method for identifying an error representative of the difference between the torque reference value and the torque applied to the machine and... | 08/22/2006 |
| 7066854 | Hybrid electric vehicle A hybrid electric vehicle comprises an internal combustion engine, a starter/generator (SG), a motor control module (MCM), a traction motor (TM), a clutch, and a battery. The engine provides power to SG to generate poly-phase alternating current; it also drives the ... | 06/27/2006 |
| 7042227 | Current determination in a permanent magnet electric machine A method and system for determining a torque current in an electric machine coupled to a polyphase bus. The method comprises: detecting a rotational position of the electric machine with a position encoder; controlling an inverter comprising a plurality of switching... | 05/09/2006 |
| 6977478 | Method, system and program product for controlling a single phase motor A controller is provided for transitioning a drive signal to a single phase motor between a square wave and pulse width modulation modes, wherein the drive signal is in square wave mode at low motor frequencies and in pulse width modulation mode during normal operat... | 12/20/2005 |
| 6930471 | Hybrid synchronous/induction generator power plant A power generation plant comprising a power generating unit that includes at least one first generator, such as an induction generator, coupled to at least one synchronous generator having a rotor with a superconducting (SC) coil. The induction generator and the SC ... | 08/16/2005 |
| 6870348 | Rotor resistance adaptation for indirect field oriented control of induction machine An induction machine includes a rotor having rotor flux and a rotor resistance. The induction machine outputs first and second reference current values. A control system includes a first controller that outputs first and second reference voltage values to the induct... | 03/22/2005 |
| 6051953 | Brushless exciterless field system for AC synchronous machines A three phase AC motor which rotates at the synchronous speed determined by the number of poles of its main stator winding and the frequency of the AC input to it, which does not need any exciter machine or brushes to provide its DC field current, but has... | 04/18/2000 |
| 5410236 | Device to regulate the speed of an electric motor and its method of operation Digital device to regulate the speed of an electric motor having a commutating element mounted in series with the motor at the terminals of an A.C. distribution network. A duration of an on-state of the commutating element defines values corresponding to ... | 04/25/1995 |
| 5396161 | Temperature compensator circuit for an induction motor The purpose of this invention is to provide secondary resistance low temperature compensation in vector speed control at values that are close to the actual secondary time constant even at startup of the motor wherein the secondary time constant operation... | 03/07/1995 |
| 5347206 | Vector control method of induction motor This invention provides a vector control method for controlling an induction motor that is used to drive an elevator based on secondary time constants, wherein the secondary time constants, which have been corrected for temperature, are determined in a sh... | 09/13/1994 |
| 5335307 | Precision electric motor speed A system and method for controlling the speed of an electric motor compares the actual speed of the motor with the desired speed of the motor. A digital comparison of the desired speed of the electric motor with the actual speed of the electric motor prov... | 08/02/1994 |
| 4956596 | Variable speed drive system An a.c. variable speed drive system which can switch between a driving operation and regenerative operation of an inverter in accordance with the operation speed. This system includes a forced commutation type inverter for controlling a wound-rotor type i... | 09/11/1990 |
| 4742288 | Control system for AC motor/generator of secondary AC excitation type A control system for controlling the load of an AC motor/generator of secondary AC excitation type connected to a power system in parallel to at least a synchronous machine. The AC motor/generator has the secondary excitation winding thereof controlled in... | 05/03/1988 |
| 4418309 | Two phase induction motor circuit with series connected center-tapped stator windings An induction motor circuit which effectively prevents voltage spikes caused by leakage inductance of the induction motor stator windings without otherwise interfering with the overall operation of the induction motor. The circuit incorporates two windings... | 11/29/1983 |
| 4074174 | Controlling apparatus for asynchronous motors with wound rotor A super-synchronous Scherbius apparatus which enables wound rotor type induction motors to have a smooth speed control below and above the synchronous speed by controlling the secondary power in either the forward or backward direction through the connect... | 02/14/1978 |
| 3939370 | Variable speed three-phase motor The disclosure is of a variable speed three-phase motor with a intermediate rotor and inner rotor, where the pack of laminations of the main rotor is prolonged as an annular pack of laminations in the direction of the longitudinal axis with short-circuit ... | 02/17/1976 |
