Antihunting Or Rate Of Change Patents (Class 322/19)
  • Patent number: 6995545
    Abstract: A fault handling algorithm processes a plurality of fault status signals from a sputtering system in a period of time to generate at least one command signal for affecting the operation of a power generator.
    Type: Grant
    Filed: August 18, 2003
    Date of Patent: February 7, 2006
    Assignee: MKS Instruments, Inc.
    Inventors: Mark D. Tracy, Jesse N. Klein
  • Patent number: 6995544
    Abstract: An IC regulator for controlling an alternator by changing contents of control in dependence on ambient temperature includes a control voltage limiter (2), a field current controller (3), a temperature sensor (4), a first comparator (5) for comparing the ambient temperature (T) with an activation temperature (TP1) and a reset temperature (TS1), and a second comparator (6) for comparing the ambient temperature (T) with a second activation temperature (TP2). The first comparator (5) outputs a limiter control signal (C2) when the ambient temperature (T) exceeds the first activation temperature (TP1) while resetting the limiter control when the temperature (T) becomes lower than the first reset temperature (TS1). The second comparator (6) outputs a field current interrupt signal (C3) when the ambient temperature (T) exceeds a second activation temperature (TP2) while resetting the signal (C3) when the temperature (T) becomes lower than the second activation temperature (TP2).
    Type: Grant
    Filed: November 7, 2003
    Date of Patent: February 7, 2006
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Katsuyuki Sumimoto, Junya Sasaki, Kyoko Higashino
  • Patent number: 6954052
    Abstract: An electronic control apparatus includes target FR calculator that calculates a target exciting current duty ratio FR based on an exciting current inputted from FR terminal of a regulator and flowing through field coil, and information of engine operating conditions. The electronic control apparatus also includes target FR limit value FRCLP calculator that calculates a FRCLP corresponding to a drive torque limit value based on an output of a correlative information detector. A comparator compares target FR and FRCLP, outputs a control signal within FRCLP to a control unit, and controls a duty ratio FR of exciting current flowing through a field coil not to be larger than FRCLP.
    Type: Grant
    Filed: November 12, 2003
    Date of Patent: October 11, 2005
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Yoshitomo Fujita, Koichi Yamane, Masami Nakashima
  • Patent number: 6919712
    Abstract: A reference voltage of an output terminal of a synchronous machine is set according to a reactive current output from the synchronous machine, a reference voltage of the high voltage side of a transformer, and a phase compensation transfer function to quicken attenuation of an electric power fluctuation.
    Type: Grant
    Filed: June 19, 2000
    Date of Patent: July 19, 2005
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Hitomi Kitamura, Masaru Shimomura
  • Patent number: 6819087
    Abstract: A power electronic based DR (distributed resource e.g., a UPS (uninterrupted power supply), Fuel Cell or Microturbine) is controlled to emulate a voltage source behind an impedance and behave as a power system stabilizer. The impedance in the DR is emulated and an estimate of impedance at the power/electronic interface is derived and applied to the control of the DR in a manner wherein the power and voltage swings on systems (loads) that otherwise would have difficulty with dynamic loads, are stabilized. Damping and synchronizing power are provided measuring only voltage, current and frequency at the interface between the DR and the load. The DR may include some energy storage.
    Type: Grant
    Filed: December 27, 2002
    Date of Patent: November 16, 2004
    Assignee: General Electric Company
    Inventors: Robert Delmerico, Gautam Sinha, Yan Liu
  • Patent number: 6801020
    Abstract: The system is directed to preserving an IC engine installation from potential overload and failure in response to electrical load increases passed along by an associated engine driven digitally controlled starter/alternator. The system controller monitors starter/alternator output and phase current and/or regulates the rate of change of output current in response to increasing electrical load. In an instance where monitored rates of output current change exceed predetermined thresholds, the response rate of the starter/alternator, i.e., rate of change of output current, is set at a predetermined threshold so as to prevent the braking effect of the increasing electrical load from stalling the I.C. engine or causing other operational failure.
    Type: Grant
    Filed: November 26, 2002
    Date of Patent: October 5, 2004
    Assignee: Dana Corporation
    Inventor: Scott Evart Blackburn
  • Patent number: 6700353
    Abstract: A battery charging system is provided for an excellent engine starting. The battery charging system includes a generator control unit for controlling output voltage of the generator and a commanding unit for providing a command pulse signal. The generator control unit includes a command pulse signal's duty-ratio detecting circuit, a generator output power limiting circuit, a voltage regulator and an activation circuit for activating the output power limiting circuit when the duty-ratio falls within a predetermined ratio range.
    Type: Grant
    Filed: April 1, 2002
    Date of Patent: March 2, 2004
    Assignee: Denso Corporation
    Inventor: Tadatoshi Asada
  • Patent number: 6426609
    Abstract: A control voltage is set to an acceleration control voltage which is higher than a battery voltage V by a predetermined voltage difference &Dgr;V1 within a range and delayed by a predetermined time &Dgr;T1 during acceleration at low speeds. During acceleration at low speeds, the rotational speed is less than a predetermined value and the rate of increase in rotational speed is equal to or greater than another predetermined value. The range of voltage is higher than battery voltage V and lower than the steady state control voltage of 14.5V.
    Type: Grant
    Filed: December 22, 2000
    Date of Patent: July 30, 2002
    Assignee: Denso Corporation
    Inventors: Koji Tanaka, Makoto Taniguchi, Takeshi Sada
  • Publication number: 20020097026
    Abstract: A method of operating an alternator of a motor vehicle includes the steps of monitoring an amount of stored electrical energy available to operate the vehicle, estimating a vehicle electrical load, and regulating an output of the alternator based at least in part on the amount of electrical energy available to the vehicle and the estimated vehicle electrical load.
    Type: Application
    Filed: January 25, 2001
    Publication date: July 25, 2002
    Inventors: Andrew James Kernahan, David Chronowski, Mark Allen Halseth, Roger William Maynard
  • Patent number: 6351692
    Abstract: A genset controller that is configurable for controlling a variety of types of gensets, as well as a method of configuring a genset controller for controlling a genset, are disclosed. The genset controller includes a memory for storing a plurality of software routines, a personality profile data set, and a user-settable data set, and further includes a processor coupled to the memory for executing the software routines and reading data from the personality profile data set and the user settable data set to control the genset. The genset controller additionally includes an input port coupled to the memory for enabling changes to the personality profile data set and the user-settable data set to be downloaded into the memory. The personality profile data set and the user-settable data set include data that configures the genset controller for operation with a particular genset.
    Type: Grant
    Filed: October 24, 2000
    Date of Patent: February 26, 2002
    Assignee: Kohler Co.
    Inventors: Zane C. Eaton, Jonathan D. Churchill
  • Patent number: 6337561
    Abstract: A generating system having a rotating type generator to interconnect a power system in order to output power of the generator to the power system comprises a generator, an exciting circuit and an excitation control section. It also comprises short-cycle stabilizing sections for outputting a short-cycle stabilizing signal for suppressing short-cycle power fluctuations according to at least one of an electric parameter and a mechanical parameter of the generator and a long-cycle stabilizing section for outputting a long-cycle stabilizing signal for suppressing long-cycle power fluctuations having a cycle time longer than short-cycle power fluctuations according to the mechanical parameter of the generator. The outputs of the short-cycle stabilizing sections and the long-cycle stabilizing section are sent to the excitation control section.
    Type: Grant
    Filed: July 13, 2000
    Date of Patent: January 8, 2002
    Assignees: Chubu Electric Power Co., Inc., Kabushiki Kaisha Toshiba
    Inventors: Yoshinari Sudou, Akira Takeuchi, Yoshinobu Mitani, Mamoru Kawasaki, Mikihito Andou, Kaiichirou Hirayama, Yoichi Uemura, Nobuo Fukushima, Toshiaki Sogabe
  • Patent number: 6265852
    Abstract: An excitation controller sets an output terminal reference voltage of a synchronous machine from a reactive current output from the synchronous machine and a high side reference voltage of a transformer, and controls the field current supplied to the field winding of the synchronous machine in response to the deviation between the reference voltage and the output terminal voltage. Although a conventional excitation controller can maintain the transmission voltage on the transmission bus at a fixed value, an expensive potential detector is needed for detecting the transmission voltage on the transmission bus, which increases the manufacturing cost of the excitation controller.
    Type: Grant
    Filed: September 20, 1999
    Date of Patent: July 24, 2001
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Hitomi Kitamura, Seiichi Tanaka, Masaru Shimomura
  • Patent number: 6218814
    Abstract: A device for voltage regulation for a generator driven by an internal combustion engine is described in which the voltage regulator is equipped with a load response travel function (LRF), which prevents a rapid rise in the exciting current when a powerful electric consumer is turned on. By means of a suitable trigger circuit which evaluates the engine rpm and thus the generator rpm, the load response travel function is blocked during travel when rpm values are falling, so that in this case, the voltage incursions that occur during an active load-response function are maximally averted.
    Type: Grant
    Filed: March 18, 1999
    Date of Patent: April 17, 2001
    Assignee: Robert Bosch GmbH
    Inventors: Walter Kohl, Rainer Mittag, Guenter Nasswetter, Helmut Suelzle
  • Patent number: 6175217
    Abstract: A hybrid generator set comprises an engine/generator or another controllable electrical source which provides a variable voltage electrical output, this output is rectified and fed to a DC to DC converter, the output (VDC) of which is monitored by a control circuit. This output serves as an intermediate DC output, which typically is used to power an inverter to generate an AC output which supplies an external load. The use of the DC to DC converter isolates the intermediate DC output from the generator output, and allows the generator set to operate efficiently over a wide engine/generator speed range, according to load demand.
    Type: Grant
    Filed: June 18, 1999
    Date of Patent: January 16, 2001
    Inventors: Manuel Dos Santos Da Ponte, Lech Grzesiak, Wlodzimierz Koczara, Pawel Pospiech, Andrzej Niedzialkowski
  • Patent number: 6130523
    Abstract: A generator transfer function regulator incorporating two control loops. The first control loop produces a first generator excitation control signal (U) which varies to compensate for variations in the magnitude of the generator output voltage (V.sub.1) . The second generator loop produces a second generator excitation control signal (U.sub.e) which varies so as to maintain substantially constant the response of the generator system to variations in the generator output. The two control signals are combined and applied to a conventional generator exciter circuit (2). As a result, the generator terminal voltage (V.sub.1) control performance achieved by the AVR under open circuit conditions is effectively maintained when the generator is loaded over its range of operation, irrespective of the power system which the generator feeds.
    Type: Grant
    Filed: September 24, 1999
    Date of Patent: October 10, 2000
    Assignee: Rolls Royce Power Engineering Plc
    Inventors: Frank Michael Hughes, Mohammad Sadegh Ghazizadeh
  • Patent number: 6087791
    Abstract: To obtain a control apparatus for a Diesel-electric locomotive that harmonizes an engine power with a torque command of an induction motor, which is a load of an engine, in the Diesel-electric locomotive and avoids an overload of the engine.A cooperative controller 15 is provided, the controller 15 which receives a notch signal N, an engine speed command value n* corresponding to the notch signal N, an engine speed n, and rotating speed fr of an induction motor 17, calculates a torque command value Tp corresponding to the engine speed n from torque command values before and after the notch signal changing during response time for control of the engine speed if the notch signal N changes, and calculates the torque command value Tp corresponding to the notch signal N after a notch is changed, except the case thereof. Furthermore, the torque command value Tp is outputted to an inverter controller 20.
    Type: Grant
    Filed: March 15, 1999
    Date of Patent: July 11, 2000
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventor: Takafumi Maruyama
  • Patent number: 6057672
    Abstract: A control signal processor effects control to permit or inhibit the passage of an input signal, by a logic operation, based on a ratio of input and output signals of a filter circuit having a double differentiation function characteristic.
    Type: Grant
    Filed: November 5, 1998
    Date of Patent: May 2, 2000
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Yuou Xia, Masaru Shimomura
  • Patent number: 5923151
    Abstract: A motor vehicle electrical system having an engine-driven generator for supplying electrical loads on the vehicle, and a semiconductor switch connected in series with the field winding of the generator for on-off control of its excitation. The generator output voltage is constantly compared with a reference voltage in order to provide a duration modulated pulse signal. During steady-state operation, when the sensed generator voltage develops higher than the reference voltage during each prescribed period of time, the switch is biased on and off by the first duration modulated pulse signal. In the event of an abrupt rise in energy requirement from the loads, when the sensed generator voltage does not grow higher than the reference voltage within the preset time, a second duration modulated pulse signal is applied to the switch in order to make progressively longer the excitation periods of the generator field winding.
    Type: Grant
    Filed: April 9, 1998
    Date of Patent: July 13, 1999
    Assignee: Sanken Electric Co., Ltd.
    Inventor: Kiyokatsu Satoh
  • Patent number: 5905357
    Abstract: A power generation control apparatus to be used for a motorcar power distributor can effectively prevent any excessive charging current from flowing into the battery and consequently protect the battery against degradation. Additionally, it can minimize fluctuations in the supply voltage and functional failures in the loads of the electric equipment of the motorcar. The power generation control apparatus to be used for a motorcar power distributor comprises an alternator for generating an alternating current to be subjected to full-wave rectification by means of a rectifier to produce a direct current, said alternator being connected to the power supply route from the battery by way of an alternator supply line at a point immediately upstream relative to the branch point for branching the power supply so that the battery may be charged with power generated by the alternator and the loads may be fed respectively with the branched power supply.
    Type: Grant
    Filed: March 18, 1997
    Date of Patent: May 18, 1999
    Assignee: Yazaki Corporation
    Inventor: Nozomi Kawasaki
  • Patent number: 5754030
    Abstract: Duty ratio of a power switching transistor connected to the field coil is controlled according to whether or not a high-power load is connected. When the high power load is not connected, the duty ratio is made 60%, for example, so that excessive power not generated. On the other hand, when the high power load is connected, the duty ratio is increased to 100% so that full power is generated by the generator. The power switching transistor is also controlled according to the battery voltage in a well known manner.
    Type: Grant
    Filed: July 16, 1996
    Date of Patent: May 19, 1998
    Assignee: Nippondenso Co., Ltd.
    Inventors: Fuyuki Maehara, Tadatoshi Asada, Yasuhiro Takase, Wakako Kanazawa
  • Patent number: 5631543
    Abstract: A method for controlling an AC generator includes a first step of varying the duty cycle of a pulse width modulated signal as a function of an output voltage appearing across at least one output winding so as to increase the duty cycle as the output voltage decreases and to decrease the duty cycle as the output voltage increases. A second step controls the current flow within a rotor winding in accordance with the pulse width modulated signal so as to decrease the current flow when the output voltage increases and to increase the current flow when the output voltage decreases. The method further includes the steps of (a) monitoring a current flow through the at least one output winding so as to detect an unloaded condition and, in response to detecting an unloaded condition, (b) delaying a first predetermined period of time; and (c) initiating an idle condition by slowing the speed of the drive engine.
    Type: Grant
    Filed: March 21, 1995
    Date of Patent: May 20, 1997
    Assignee: Homelite Inc.
    Inventor: Christopher L. Watson
  • Patent number: 5604420
    Abstract: The stabilizer for power system is capable of suppressing power unstableness quickly and functioning effectively to a plurality of power disturbances even if the non-linearity of the power system becomes more intense because the stability point is moved from optimum stability. A phase difference calculating circuit calculates the phase difference between the internal phase angle of a generator and the voltage phase in a secondary bus line of a main transformer connected to a synchronous generator. A power system stabilizer produces an auxiliary signal based on the output of the phase difference calculating circuit. A first nonlinear compensating circuit and a second nonlinear compensating circuit produce compensating signals for compensating the non-linearity of the power system in order to compensate the output of the power system stabilizer.
    Type: Grant
    Filed: March 17, 1995
    Date of Patent: February 18, 1997
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventor: Masahiko Nambu
  • Patent number: 5497069
    Abstract: An electronic voltage regulator for generators controlled by means of an exciter field current, comprises an average voltage sensing circuit connected to the output of the generator, a peak voltage sensing circuit connected to the output of the generator, an error signal circuit operatively connected to the average voltage sensing and the peak voltage sensing circuits effective to generate an error signal when the generator's average output voltage varies from a predetermined value or when the peak voltage exceeds a predetermined limit, an exciter field current control circuit operatively connected to the error signal circuit effective to control the generator field current in response to the error signal, and a shock load stabilization circuit operatively connected to the average voltage sensing circuit and to the peak voltage sensing circuit effective to disable the peak voltage sensing circuit upon sensing an application of a shock load to the generator.
    Type: Grant
    Filed: June 24, 1994
    Date of Patent: March 5, 1996
    Assignee: Sundstrand Corporation
    Inventors: Michael H. Shriver, Rich A. Helm
  • Patent number: 4855664
    Abstract: A scheme for stabilizing a synchronous alternating current generator through the excitation control to dampen generator oscillations includes a power system stabilizer responsive to signals representing the generator output voltage and output current to provide an oscillation signal which represents the instantaneous magnitude of the generator oscillations. A modulator means is included which develops a signal, representing the generator voltage with respect to neutral, and this latter signal is multiplied by the oscillation signal to provide a control signal which controls the excitation of the generator.
    Type: Grant
    Filed: June 10, 1988
    Date of Patent: August 8, 1989
    Assignee: General Electric Company
    Inventor: Lawrence J. Lane
  • Patent number: 4701689
    Abstract: The present invention relates to an automatic device for depressing low frequency oscillation of power system. It consists of an electronic circuit incorporated in the original excitation regulator of a synchronous generator. This circuit can turn the input deviation of voltage .DELTA.V into simulating state variable deviations of angular frequency .DELTA..omega., of power .DELTA.P and of power angle .DELTA..delta., and then outputs the sum of them according to the principle of optimal control. With the device of the present invention, the output capability of a remote power station may double, a whole set of measurement and feedback devices may be spared and the distortions in measurement may be avoided. The present device has further advantages of being small in size, cheap in cost, easy to establish and high in reliability.
    Type: Grant
    Filed: April 4, 1986
    Date of Patent: October 20, 1987
    Assignee: Huazhong Institute of Technology
    Inventors: Ren Yuan, Chen Xianzhi, Feng Yuanxi, Li Guojiu, Huang Dake, Zhang Yongli, Sun Quanzhong
  • Patent number: 4656413
    Abstract: A stabilized control system and method for smoothly connecting and disconnecting an induction generator to the utility power grid is described. Thyristor switches are interposed between each phase of the mains and the generator. The thyristors are gated so as to decouple the generator from the mains for a period during each mains half-cycle, the decoupling period decreasing as the generator power factor angle increases as the generator is driven by the prime mover to its synchronous speed and above. A feedback circuit processes the generator terminal voltage to produce an analog feedback signal level proportional to the thyristor blocking voltage. The feedback signal is used to increase the thyristor gate delay angle as the generator voltage increases with increasing generator output power. This causes the rate-of-change of the generator voltage with respect to generator speed to be less than it would be with no feedback signal present.
    Type: Grant
    Filed: June 19, 1986
    Date of Patent: April 7, 1987
    Inventor: Frank J. Bourbeau
  • Patent number: 4426613
    Abstract: A control circuit for a self-excited AC generator including an automatic voltage regulator, a fly-wheel capacitor which is charged normally by part of the generator output during a no-load operation or small-load operation of the generator, a detection circuit which detects a drop of the generator output voltage when said output voltage drops below the predetermined value, and a field current control circuit which operates on the fly-wheel capacitor to discharge the stored electric energy to the field winding of the generator or an exciter equipped with the generator when the detection circuit detects a drop of the generator output voltage. The control circuit provides additionally with the second field current control circuit which supplies a current from the generator output terminal to the field winding through a rectifier when the detection circuit detects a drop of the generator output voltage.
    Type: Grant
    Filed: March 23, 1983
    Date of Patent: January 17, 1984
    Assignee: Hokuetsu Industries Co., Ltd.
    Inventors: Masamitsu Mizuno, Kazuomi Itoh, Masahiro Urushibara
  • Patent number: 4399397
    Abstract: A digital electronic governor controls and stabilizes the electrical power output delivered to an output circuit by an AC alternator having a rotating shaft driven by a source. The governor provides a first relatively fast acting governing function operatively responsive to phase shift of the electrical power output relative to the rotating shaft corresponding to changes in load at the output circuit. The first governor stabilizes the phase shift of the electrical power output at a specified phase lag interval relative to the shaft rotation. The electronic governor also provides a second governing function operatively responsive to relatively slower inertial changes in the speed of rotation of the shaft, corresponding to changes in the power level of the AC alternator. This second governor stabilizes the rotating shaft at a specified speed of rotation, e.g., 60 cycles per second. The first governor generates load signals in response to the measured phase shift deviation from a standard phase lag interval.
    Type: Grant
    Filed: April 17, 1981
    Date of Patent: August 16, 1983
    Assignee: R. Stevens Kleinschmidt
    Inventor: Robert S. Kleinschmidt, Jr.
  • Patent number: 4393345
    Abstract: A circuit for damping hunting oscillations of controlled electric machines. The circuit is provided with a measuring circuit for determining the hunting oscillations and an identifier circuit for determining the angle components of such hunting oscillations. A phase shifter circuit is provided for receiving the angle components produced by the identifier circuit and forming a hunting oscillation correction signal which is shifted in phase from the hunting oscillations by a predetermined phase angle. The hunting oscillation correction signal is conducted to a control unit of the electric machine. The invention is particularly useful in damping hunting by the rotors of voltage controlled synchronous generators.
    Type: Grant
    Filed: October 22, 1980
    Date of Patent: July 12, 1983
    Assignee: Siemens Aktiengesellschaft
    Inventors: Kurt Fork, Wolfgang Kaufhold, Wolfgang Meusel, Hermann Waldmann
  • Patent number: 4376295
    Abstract: There is disclosed a system for predicting desynchronization of a synchronous machine by detecting a phenomenon of radical variation of the magnetic flux in the gap of a synchronous machine immediately before falling in an asynchronous state. For example, a functional value of the fundamental harmonic component and that of the higher harmonic component of the flux in the gap are detected for comparing the variation of each functional value with a predetermined reference level to predict desynchronization of the synchronous machine.
    Type: Grant
    Filed: March 15, 1982
    Date of Patent: March 8, 1983
    Assignees: Fuji Electric Co. Ltd., Yoshizo Obata
    Inventors: Chikasa Uenosono, Takao Okada, Junya Matsuki, Tadashi Naito, Shinichiro Inoue, Yoshizo Obata
  • Patent number: 4350947
    Abstract: Desynchronization of a synchronous machine is predicted by detecting a phenomenon of radical variation of the magnetic flux in the gap of a synchronous machine immediately before falling into an asynchronous state. For example, each functional value of the direct axis flux and the quadrature axis flux in the gap is detected for comparing the variation of each functional value with a predetermined reference level to predict desynchronization of the synchronous machine.
    Type: Grant
    Filed: February 25, 1980
    Date of Patent: September 21, 1982
    Assignees: Fuji Electric Co. Ltd., Masaki Takahashi
    Inventors: Chikasa Uenosono, Takao Okada, Junya Matsuki, Tadashi Naito, Shinichiro Inoue, Masaki Takahashi
  • Patent number: 4326159
    Abstract: Voltage, current and field voltage of a generator connected to an electric power system are sampled at a predetermined period for analog-digital conversion and then led to a digital computer. In addition to computation for AVR, the computer computes from its input the generator output power, and also monitors the occurrence of a fault, the removal of the fault and variation in the generator output in the system. After the occurrence of a fault, the field excitation of the generator is intensified until the generator output power reaches substantially a peak value, but after the peak value is substantially passed by, the excitation is conversely depressed to a value below the level which is present before the fault occurs. When the generator output power recovers the value which is present before the fault occurs, the computer returns to deliver the AVR output.
    Type: Grant
    Filed: August 30, 1979
    Date of Patent: April 20, 1982
    Assignees: Hitachi, Ltd., Hitachi Engineering Co., Ltd.
    Inventors: Hiroaki Aotsu, Akira Isono, Tsutomu Inayama, Mamoru Fukushima
  • Patent number: 4032835
    Abstract: An excitation system for a synchronous generator includes a conventional brushless exciter for providing base excitation for rated power output and a controlled source of direct current interconnected with the conventional brushless excitation system to supplement the base excitation. The supplementary excitation is supplied to the rotating field winding of the synchronous generator to provide forcing excitation to permit operation of the generator at power levels which exceed the generator's base power output level.
    Type: Grant
    Filed: March 15, 1976
    Date of Patent: June 28, 1977
    Assignee: Westinghouse Electric Corporation
    Inventors: Leonard W. Finnell, Sigrud R. Petersen, Dale I. Gorden