Abstract: Voltage regulation of a DC electrical power source having a generator with an exciter field coil for producing an AC output voltage which is rectified to produce a DC output voltage, is accomplished by producing voltage signals proportional to the AC output voltage of the generator and the current in the generator exciter field winding, and combining these signals to produce a control signal. An additional voltage signal proportional to the DC output voltage of the power source is compared to a DC reference voltage signal to produce a trim error voltage signal. The trim error voltage signal is combined with an AC reference signal to produce an additional control signal. These control signals are compared and the result of that comparison is used to control the current in the generator exciter field winding.

Abstract: A voltage regulator for a diesel engine driven alternator includes speed dip control permitting engine recovery, and a voltage signal circuit and a speed signal circuit producing a linear volts per hertz signal for controlling the RMS voltage of the alternator. A speed sensor is connected to the output of the permanent magnet generator. The signal is a filtered square wave with an accurate 50% mark-to-space ratio and converted to a pulse train coincident with the zero crossovers. A ramp circuit followed by a threshold detector and filter produces a linearly increasing voltage with decreasing speed. A level amplifier produces an output at a selected level. A rate amplifier responds to a derivative of the speed signal and clamps the level amplifier off at speed changes below a selected rate. A large and rapid speed change creates an output signal coupled to the reference side of an error amplifier to unload the alternator. The degree and rate of unloading is limited.

Abstract: A power level indicator is described for use with an electric generator for indicating to the operator the percentage of the total power available from the generator which is being consumed by a load.

Abstract: A parallel power system includes at least two DC link variable speed constant frequency power sources each having a plurality of output phases connected to a common bus. The total real error current flowing in the output phases of each of the power sources is monitored and the relative phase angle of the Thevenin voltage of the power sources is controlled in response to the monitored total real error current to reduce the magnitude of this real error current. The reactive error current flowing in at least one of the output phases of each of the power sources is monitored and the relative magnitude of the Thevenin voltage of the power sources is controlled in response to the monitored reactive error current to reduce the magnitude of the reactive error current. For operation at no load, the phase angle control loop is sensitive to both real and reactive error currents.

Abstract: A self-excited brushless AC generator as a single or polyphase main winding, a generator field winding, an exciter device for drawing current from the main winding for energizing the generator field winding when the main winding is under no load and normal load conditions and an auxiliary exciter system responsive to the generation of a harmonic of the generator fundamental flux to supply current to the exciter device for energizing the field winding when the main winding is under short circuit conditions. The auxiliary exciter system has an auxiliary winding wound with the main winding so as to be responsive to generation of the harmonic flux and an automatic voltage regulator. The regulator has a first input coupled to the auxiliary winding, a second input coupled to an output of the generator and an output coupled to an exciter field winding which is inductively coupled to an armature winding of the exciter device.

Abstract: A control apparatus for a vehicular generator for use in an automobile, etc., in which the temperature of the generator is detected so as to control switching of the field current of the generator when the temperature of the generator is below a predetermined value, so that the cold output current and cold drive torque of the generator are substantially the same as the hot output current and hot drive torque of the generator.

Abstract: Transfer apparatus for use with an AC generator having a field winding, the DC energization of which controls the output of the generator. Associated with the generator are first and second voltage regulators each including means for sensing the output of the generator and means for varying the DC energization of the generator field winding to regulate the output of the generator to a respective reference level for each voltage regulator. The transfer apparatus includes a circuit for generating a first signal as a function of the generator output as sensed by the first voltage regulator sensing means and a second signal as a function of the generator output as sensed by the second voltage regulator sensing means. Another circuit independently produces an additional signal to which the first and second signals ordinarily have a predetermined relationship. A further circuit selects the first or second voltage regulator to energize the generator field winding.

Abstract: An alternator control system for controlled charging of a secondary battery such as a lead-acid battery, the invention allows manual selection of alternator output current. The control system of the invention is connected to the alternator field terminal in parallel to the voltage regulator. The selected alternator output current is essentially constant to allow estimation of the time necessary to charge a given number of ampere hours. The present control system also incorporates a voltage sensing cutoff circuit which disconnects the control system from the alternator when the battery has reached full charge, when the selected charging current becomes excessive as the battery approaches full charge, or when a charging current is selected which is excessive for the capacity of a given battery.

Abstract: A balance vehicle speed at which mean charging current and mean discharging current are balanced is obtained. A charge stop vehicle speed corresponding to the balance vehicle speed is decided as a reference value. An actual vehicle speed is compared with the charge stop vehicle speed to produce a charge stop signal, when the actual vehicle speed is lower than the charge stop vehicle speed. A charging regulator is responsive to the charge stop signal for disabling the regulator so as to stop the charging of a battery.

Abstract: A protection circuit for a charging generator against a short-circuit of a field winding of an a.c. generator included therein is disclosed, in which an output transistor of a voltage regulator of the charging generator is on-off controlled when a collector current of said output transistor exceeds a predetermined high value.

Abstract: A control apparatus incorporated in a charging generator for controlling interruption of an exciting current supplied to a field winding of the charging generator comprises a power transistor for intermittently interrupting the exciting current, a voltage detecting circuit for controlling on-off of the power transistor depending on the voltage generated by the charging generator, a current detecting circuit for detecting an initial exciting current supplied to the field winding until the charging generator generates an output voltage high enough for starting its charging operation, and a circuit for turning off the power transistor as soon as the value of the current detected by the current detecting circuit exceeds a predetermined setting.

Abstract: A voltage regulator for use with a source, such as a generator, and a load, such as a battery for limiting the current delivered by the source to the load at one of a plurality of selectable current limit levels. The regulator comprises a regulation circuit, an over voltage protection circuit and a current limiting circuit. The current limiting circuit includes a shunt resistor to sense the current flowing between the source and the load and a switch to permit selection of a single limit level from the plurality of limit levels. The switch may be manually or automatically controlled. The current is limited by generating an over current signal to the over voltage circuit which, in response, reduces the output of the source.

Abstract: A charge control microcomputer is provided for a vehicle charging system to control the reference voltage employed by the voltage regulator so that a suitable battery charging voltage is generated at all times. The microcomputer processes charging system data such as the battery output voltage, the generator output current, etc., and at least one engine parameter from an engine control microcomputer to derive the most suitable reference voltage for the voltage regulator.

Abstract: Various malfunctions of a DC generator equipped with a voltage regulator and malfunction indicator are indicated distinguishably by detecting terminal voltages of a field winding and an armature winding of the DC generator and supplying a signal to the malfunction indicator, the signal being variable according to the type of malfunction. For example, the lighting interval of an indicator lamp is varied in accordance with the type of malfunction.

Abstract: A charge control system for a vehicle is provided with a microcomputer which calculates the most suitable battery charging value or voltage regulator set value on the basis of detected engine and charging system parameters. The microcomputer uses parameters such as the charging condition and service life condition of the battery, along with the instantaneous generated voltage, etc., and outputs the calculated set value to the voltage regulator of the charging system.

Abstract: A microcomputer implemented apparatus and method for detecting the occurrence of a shorted diode in the rotating rectifier of a brushless alternator. The alternator current, voltage and power output and the alternator temperature are measured. The anticipated exciter field current is determined for the alternator output and operating conditions and compared with the actual exciter field current. An actual exciter field current in excess of the anticipated current indicates a rectifier fault.

Abstract: In a voltage regulator for a generating system having a main generator and an exciter, the exciter providing field current to the main generator, it is desirable to provide a maximum current limit on the generator output which also allows the voltage regulator to maintain excitation during a fault condition. The voltage regulator of the present invention includes a maximum current limit circuit which detects not only a high current condition, but also the number of phases in a polyphase generator output in a fault condition. The voltage regulator thereby limits the maximum current each type of fault can produce, thus providing highly desirable system characteristics for clearing faults, tripping circuit breakers and prolonging generator life.

Abstract: A voltage regulator for a generating system having a main generator and an exciter for providing field current to the main generator includes means coupled to the main generator for sensing at least two operating parameters thereof. Means are coupled to the sensing means for generating pulse width modulated (PWM) signals based upon the first and second sensed operating parameters. Means are coupled to the first and second PWM signals for comparing the pulse widths thereof. The PWM signal having the narrower pulse width is coupled to a switch for controlling the current delivered to the exciter. The exciter current is therefore controlled in accordance with one of the sensed parameters at any particular time.

Abstract: An electric generating device of the self-excited, self-regulated, brushless, synchronous type includes an alternator-exciter for producing an electrical output and an adjusting means for adjusting or setting the output voltage of the alternator-exciter substantially independently of the winding arrangement thereof to control the no-load or light load voltage of the electrical output. A deactivating device deactivates the adjusting control when maximum field current is demanded by a load.

Abstract: An electrical distribution system has parallel connected generators powered by variable speed engines. Loads connected with each generator are interconnected through an electrical distribution bus. Constant speed drives have inputs connected with the engines and outputs directly connected with the generators. The connections between the constant speed drive outputs and the generators are characterized by the absence of overrunning clutches used in prior systems. An improved electrical protective circuit senses a flow of electrical power from the distribution bus to a generator, driving the generator as a motor. If the power flow to the generator is excessive, the bus tie breaker is opened disconnecting the generator from the bus.

Abstract: A motor driven generator has a generator control unit which incorporates a programmed microprocessor to control generator operation. A generator voltage regulator utilizes the microprocessor of the generator control unit to develop an error voltage which is added to the average phase voltage of the generator, controlling the generator field current. In the event of a phase failure the generator control unit senses an abnormally high phase voltage condition, disables the average phase voltage circuit. In the event of an abnormal difference between the high and low phase voltages, the gain of the error signal circuit is reduced.

Abstract: A D.C. welder includes an engine-driven D.C. generator, a polarity-revers switch which can change the direction of current flow through the field winding of that generator to provide a positive or negative polarity at the welder output terminals, a circuit that automatically permits only uni-directional current flow through that field winding during the starting of the engine, and a further circuit that energizes a solenoid to close contacts which enable that generator to operate as the starting motor for that engine but which thereafter de-energizes that solenoid and then keeps it de-energized until the engine is at, or close to, rest.

Abstract: A microprocessor based, power systems stabilizer operating through excitation control wherein all required stabilizing information is derived from sampled values of voltage and current taken from potential and current transformers. The instantaneous values of terminal voltage and current are processed using algorithms in the accelerating power signal digital processor portion of the microprocessor to thereby develop a value of instantaneous internal voltage, the value of slip frequency of such voltages in relation to rated frequency and a digitally filtered value of electrical power. The accelerating power is calculated from the rate of change of slip and electrical power. The values of accelerating power are processed with digital algorithms in a stabilizing signal compute section of the microprocessor to yield a stabilizing signal which provides the desired modulating action for damping the machine oscillations of the synchronous generator.

Abstract: Signal conditioning apparatus for reducing the noise frequencies of a speed sensing means signal being fed into a compensating means for compensating the output of a synchronous generator for the effect of torsional oscillation between masses in the main AC generator system. The signal conditioning apparatus includes two speed sensing transducers mounted 180.degree. apart on opposite sides of a tooth gear wheel and summing the two FM output signals from the transducers to eliminate odd harmonics of the synchronous frequency in FM noise due to eccentricity. The preferred embodiment of the invention reduces the remaining noise from the sensed speed signal by the use of a three-pole Butterworth low-pass filter in combination with a notch filter tuned to the turbine-generator synchronous frequency to thereby reduce the unwanted noise to a large degree while providing a minimal phase shift to the sensed speed signal.

Abstract: A voltage regulator for aircraft generators controls generator output voltage by controlling exciter field current. Exciter field current sensors and generator output voltage sensors produce control signals which are proportional to exciter field current and generator voltage. These signals are combined and compared with a reference voltage signal by a comparator. A current controller regulates exciter field current in response to the comparator output.

Abstract: A generator system which is self-excited even during a fault condition includes a main generator having armature windings and a main field winding which is excited by a rotary transformer. The rotary transformer includes a stationary primary winding and a rotating secondary winding, with the primary winding receiving a controlled portion of the main generator armature output. The current through the primary winding of the transformer is controlled by silicon controlled rectifiers which are gated by a voltage regulator circuit. The voltage regulator circuit in turn receives signals from the voltage delivered to the load, the highest phase current delivered to the load and the voltage at the main generator armature output. The voltage regulator controls the current through the primary winding of the transformer in accordance with the voltage delivered to the load if that voltage is greater than a predetermined value.

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.

Abstract: A system for supplying power to a field winding to maintain excitation of an alternating current generator during excessive output current conditions, the generator having a plurality of output lines for supplying power to a load and the field winding being supplied during normal operating conditions by a shunt type voltage regulator responsive to the output voltage of the generator. The system includes a current transformer having a primary winding in series with an output line of the generator, a secondary winding, and a tertiary winding shunted by a capacitance. A rectifier circuit rectifies the voltage supplied by the secondary winding, the output terminals of the rectifier circuit being connected in series with the regulator output terminals to supply power to the field winding. A control circuit, connected to the output of the generator and responsive to output current conditions enables the rectifier circuit output during excessive output conditions.

Abstract: A device for detecting current imbalance between phases of a polyphase alternating current generator. A detector responds to the maximum peak current in the generator, and detecting means generates an output for each phase proportional to the peak current of each phase. Comparing means generates an output when the maximum peak current exceeds the phase peak current.

Abstract: The shaft of a wind turbine is connected to the rotor of a three-phase AC generator. The rotor windings, in turn, are connected to the rotor windings of a DC-energized, AC exciter via a differential frequency-converter. A frequency-detector, which monitors the output of the AC generator, is connected to the input of the frequency-converter to maintain the output of the generator at 60 Hz. A "real" power sensing circuit, connected to the output of the generator, develops a control signal which, when subtracted from a second control signal generated by a power management control circuit, maintains the power output of the generator at the maximum possible level for each particular power output from the wind turbine which drives the generator.

Abstract: A voltage regulator circuit provides multiple control functions in respect to an automotive alternator including limiting of the field current to within a predetermined level. The regulator circuit includes a current control device for controlling the alternator field current, and a plurality of comparator networks to one of which is applied a field current reference signal and a sensing signal and to others of which are applied various alternator voltage reference signals and voltage sensing signals. The outputs of said comparator networks are employed in an OR fashion to control the field current control device.

Abstract: Apparatus is disclosed for continuously monitoring the air gap torque acting on the rotor of a 3-phase electrical generator by sensing certain of the output voltages and currents produced by the generator as it supplies power to a connected load. In a preferred form of the invention, signals representing the three generator output voltages and two of the three line currents are conditioned and combined in electrical circuitry to produce a single output signal which is indicative of the air gap torque. The torque signal so produced is in a form easily handled by conventional means such as computers and recorders, and is appropriate for use by operating personnel in making decisions regarding generator operation.

Abstract: A voltage regulator for regulating the supply of power by a fixed field A.C. generator which generates current to charge a battery, including an openable and closeable current charging path being connectable between the fixed field A.C. generator and the battery, a circuit which senses battery voltage and generates control signals in response to the voltage being above or below a predetermined level, and a circuit, responsive to the control signals, which opens and closes the current charging path and which reduces the power supplied by the generator when the current charging path is opened. The voltage regulator also has an over-current protection circuit, and circuits for indicating over-voltage and under-voltage battery conditions.

Abstract: A voltage regulator which regulates field current through a controlled field generator used to charge a battery, including a battery voltage sensing circuit which generates logic control signals in response to the battery voltage being above or below a predetermined level, an over-current sensing circuit which generates logic control signals in response to the charging current of the generator being above or below a predetermined level of charging current, a logic gate for gating the logic control signals, and a control circuit responsive to the signals from the logic gate to continue or interrupt field current through the field winding.

Abstract: A shaft torsional oscillation signal of a rotatable torsional system including a rotor of a synchronous machine, at least one rotatable body and a shaft coupling the synchronous machine and the rotatable body, is detected. The shaft torsional oscillation signal with a specific frequency is made to advance the phase thereof by a stabilizing control device. The field voltage of the synchronous machine is so controlled that a sub-synchronous resonance (SSR) of the rotatable torsional system caused by the specific frequency is restrictedly controlled by the shaft torsional signal of the specific frequency phase-advanced.

Abstract: A dynamic stabilizer of the type which is utilized to compensate or stabilize the effect of subsynchronous resonance oscillations in a turbine generator system is taught. Silicon controlled rectifiers are connected in series with inductors between the lines of the electrical system. The silicon controlled rectifiers may be maintained at two quiescent conduction intervals of 90.degree. and 135.degree. depending upon the peak value of rotor oscillation. If the peak value of rotor oscillation is sufficiently small the lower conduction interval of 90.degree. is utilized as this is sufficient to stabilize low level oscillations. Furthermore, it has great advantage in the fact that the losses represented by 90.degree. quiescent conduction interval are relatively small when compared with the larger quiescent conduction interval.

Abstract: Apparatus and method for monitoring torsional vibration in the rotor of a dynamoelectric machine by detecting electrical quantities available at the output terminals of the machine. For at least one phase of the machine, output voltage and current are detected and a composite signal is formed therefrom in signal processing circuitry. The composite signal is in synchronous phase with the mechanical angle of the rotor and may be demodulated to obtain the torsional vibration information.

Abstract: In a generating system having a shunt-type regulator for exciting the field of a generator during normal operating conditions, circuitry is provided for supplying voltage to a field winding to maintain excitation of the generator during excessive output current conditions. This circuitry senses the low voltage indicative of a fault or overload condition and in response boosts the field of the field winding during such an excessive output current condition an amount sufficient to maintain generator excitation during that particular condition. It does this by impressing a voltage, supplemental to that supplied by the regulator, upon the field winding during the condition. As a result the excitation of the generator is maintained.

Abstract: A field control apparatus for a generator having a field winding comprises a terminal voltage control unit for controlling a field current of the generator in accordance with a difference between a terminal voltage signal of the generator and a reference voltage signal, which control unit has at least one of a line drop compensation function, an under-excitation limitation function, an over-excitation limitation function, a power factor regulation function, an armature winding over-current compensation function and a cross-current compensation function. The field control apparatus includes a detector as a common signal source for detecting active power and reactive power components at an output terminal of the generator and means responsive to the output of the detector for performing scalar operation in accordance with a function of the added compensation/control function described above.

Abstract: The stator windings of a dynamo electric machine include three phase and single phase output windings for generating alternating current output power at different voltages. The machine output voltage is kept relatively constant by means of a brushless exciter having control and compounding field windings which are energized through stationary rectifier circuits. The rectifier circuit for energizing the field windings of the exciter is connected to or near the neutral leads of the stator windings to maintain a low voltage between the diodes of the rectifier and ground. The energization of the compounding field winding is controlled by means of a variable resistor in dependence upon whether the load connected to the dynamo electric machine is supplied with single phase or three phase current.

Abstract: A resistor, a DC source and a current converter are connected in series between one terminal of the field winding and the ground. When a ground fault occurs on the field winding, it is detected by the output of a voltage detector connected across the resistor or the output of the current converter, and an alarm device is operated. At the same time, another resistor is connected between the other terminal of the field winding and the current converter through a switch, and the magnitude of the ground fault is calculated by the outputs of the voltage detector and of the current converter before and after closure of the switch. When the magnitude of the ground fault is large the generator is disconnected.

Abstract: The alternating current output potential of an alternator is rectified by a main rectifier circuit to provide a first charging potential and by an auxiliary rectifier circuit arrangement of the type that is enabled only in response to the presence of electrical enabling signals to provide a second charging potential. The first charging potential is applied across two series connected storage batteries and the second charging potential is applied across only a selected one of batteries. The enabling signals for the auxiliary rectifier circuit arrangement are initiated by a free-running oscillator circuit and circuitry responsive to the potential across the two batteries in series and to the potential across the selected battery is arranged to disable the oscillator circuit when the potential across the selected battery is of magnitude greater than one-half that of the potential across the two series connected batteries.

Abstract: Thyristors are substituted for conventional diodes in the rotating rectifier assembly of a brushless exciter in a synchronous dynamoelectric machine. In contrast with prior systems in which thyristors are switched at relatively high ceiling voltages (requiring thyristors of high power rating and additional components for fast de-excitation), the gates of the thyristors in the present invention are fired only at a low voltage point of the negative half cycle of the polyphase armature voltage waveforms for fast de-excitation and are maintained in a fully conducting condition during the positive half cycle. This permits the use of thyristors having a relatively lower power rating and makes unnecessary additional components to achieve fast de-excitation.

Abstract: A stator conductor terminal assembly is located at the underside of the housing of a three-phase turbo-generator for leading out the phase windings from the stator coil head. The assembly includes three fully insulated liquid-cooled tubular lead-off conductors connected respectively to the phase windings and each such conductor includes a first section directed vertically downward, a second section directed horizontally for different distances and a third section also directed vertically downward and which is shielded in a metallic box-like enclosure. A current transformer surrounds the third section of the conductor within the box-like enclosure and the lower end of the third section which passes through the open bottom of the enclosure is connected to a terminal which latter is connected to an outgoing phase line. Metallic tubular shielding surrounds each phase line and this shielding is connected by way of electrically conductive bellows to the box-like enclosure.

Abstract: A dynamo electric machine including an alternating current generator and a brushless exciter for the generator field, wherein control and compounding field windings of the exciter are energized from the generator stator winding through stationary rectifier circuits, the rectifier circuit for the compounding field making connection with the generator stator winding in the vicinity of its neutral point to avoid impressing high voltage to ground on rectifiers of the circuit.

Abstract: A system for protecting a turbine-generator power plant governed by signals representative of turbine mechanical power and generator electrical power to reduce at times the turbine mechanical power, with an electronic filter included therein for the purposes of filtering a periodic time varying component of the electrical power signal having a response time within adequate protective limits, is disclosed. More specifically, the electronic filter generates a train of fixed time durations wherein during each fixed time duration the maximum and minimum amplitudes of the electrical power signal are selected. A signal is sampled at the end of each fixed time duration and held constant for each next fixed time duration, said signal being representative of the average of the maximum and minimum amplitudes selected during each fixed time duration.

Abstract: A brushless welding generator with a homopolar machine which supplies welding current, and has winding-free rotors with several pole rings. Each of these form an air gap of varying size around its periphery with the stator. The homopolar machine is divided into two electromagnetic parts, each having an exciting winding. The exciting field is controlled in one of the two electromagnetic parts in opposition to the welding current. One electromagnetic part, furthermore, has a further exciting winding fed by the welding current to control its exciting field. This further exciting winding produces an exciting field directed opposite to the exciting field of the first-mentioned exciting winding. A regulator controls the welding current of one exciting winding, and a signal derived from the welding current is applied to the regulator for representing an actual value.

Abstract: In a protective arrangement for protecting a brushless synchronous machine against overvoltage at a field winding which is connected to a rotating excitation rectifier which is fed from an exciter machine, in which the field winding is short circuited by means of a solid state switching element when overvoltages occur, a voltage comparison means is provided to which are fed as respective first and second inputs, a first input voltage proportional to the primary voltage of the exciter machine and a second input voltage proportional to the primary current of the exciter machine with the proportionality constant chosen such that for normal operation of the synchronous machine the absolute value of the second input voltage is lower than the first input voltage and for operation when the field winding is short circuited, the absolute value of the second input voltage is greater than the first input voltage.

Abstract: A load-shedding control for diesel-electric motor-generator sets, which allows temporary overloads to be accommodated without engine lugging by reducing the line voltage if an attempt is made to draw more than a presettable maximum normal wattage. The line voltage reduction is accomplished by automatically increasing the impedance of the voltage regulator input circuit when a signal generally proportional to line voltage and load current exceeds a preset reference signal to which it is compared.

Abstract: Power system stabilizers are used in the excitation systems of large shaft driven synchronous dynamoelectric machines for the purpose of enhancing the dynamic stability of power generating systems. Such stabilizers using speed, power or frequency as an input signal when applied with high initial response excitation systems are effective in damping low-frequency local or inter-tie mode oscillations which may occur in the system. The power system stabilizer may adversely affect torsional damping at higher frequencies. The adverse effects of a power system stabilizer at shaft torsional frequencies are obviated by providing a torsional oscillation protection device comprising a composite band-reject filter of the present invention which attenuates the power system stabilizer output at the shaft natural torsional frequencies without introducing an excessive phase lag at the local or inter-tie mode frequencies.