Abstract: A voltage regulator for an automotive alternator includes a switching transistor that controls an amount of field current supplied to a field coil of the alternator. The switching transistor is controlled in an ON-OFF fashion, and output voltage of the alternator is always monitored by a detector circuit that detects disconnection in a circuit for charging an on-board battery with the output voltage. It is determined that the disconnection occurred when a difference between the output voltage at a time when the switching transistor is turned off and the output voltage at a time when the switching transistor is turned on exceeds a predetermined value.

Abstract: Systems, methods and devices are described for controlling a vehicle electrical generator. A regulator for controlling a generator in response to an input signal received from a control module suitably includes a discriminator module, a processing module and a switching circuit. The discriminator determines whether the regulator is operating in voltage or torque control mode. If the input signal is a voltage control, the output generator produces a modulation signal to produce a desired voltage between two battery terminals. If the input signal is a torque control, the output generator produces one or more modulation signals (e.g. pulse width modulation signals) to control the torque of the generator. The modulation signals are applied across a field coil or other controllable element of the generator by a switching circuit that applies positive and/or negative voltage from the battery terminals as appropriate.

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).

Abstract: A generator control circuit of an ac generator which charges a battery includes a voltage regulator, a comparator which provides a control signal for controlling the voltage regulator when the output voltage of the ac generator is higher than a predetermined voltage and an alarming device which operates when the comparator does not provide the control signal. The predetermined voltage is set higher than voltage of the battery when the battery is open and equal to or lower than a regulation voltage of the ac generator.

Abstract: An engine generator, sufficiently meeting a demand for a simple configuration and easy control, is provided. The output of a generator 1 connected to an engine 2 is output through a rectifier circuit 3 and an inverter 4. The generator 1 is a dual-purpose generator both for a generator function and for an electric motor function, and is driven by a drive inverter as an engine starting electric motor. A DC—DC converter 5 is provided between the output side of the rectifier circuit 3 and the output terminal of a battery 6. The generator 1 is driven as an engine starting electric motor, using the battery 6 as a power supply, when the engine is started.

Abstract: An apparatus for calculating an effective voltage is provided, which includes a voltage reducer, an analogue to digital converter, a first detector, a second detector and a calculator. The voltage reducer steps down instantaneous output voltages of a generator. The analogue to digital converter converts each analogue signal of the instantaneous output voltages into a digital signal. The first detector detects a first signal of digitized instantaneous output voltage. The second detector detects a second signal, which differs in terms of phase by 120 deg. from the first signal. The calculator calculates an effective voltage according to the first and second signals, by executing a calculation with an expression: E={2(Va2+VaVb+Vb2)/3}1/2, where E represents the effective voltage, Va the first signal of instantaneous output voltage and Vb the second signal, respectively.

Abstract: An alternator system includes a permanent magnet alternator, battery and voltage regulator operatively connected to the permanent magnet alternator and battery for regulating the charging of the battery. The voltage regulator includes a rectifying circuit for rectifying the alternating current and a semiconductor switching element operative for turning the regulator on and off based on a predetermined temperature threshold to prevent overheating of any voltage regulator electronic components.

Abstract: A vehicular alternator failure determination apparatus is capable of making a failure determination accurately. The apparatus includes a maximum voltage detection part (1) for detecting a maximum voltage of an alternator commutating device which commutates an AC output of the alternator driven by an engine, a minimum voltage detection part (2) for detecting a minimum voltage of the alternator commutating device, a voltage difference calculation part (3) for detecting a difference voltage from outputs of the maximum and minimum voltage detection parts, and a failure determination part (4) which determines that the alternator is in a failure state, when an output of the voltage difference calculation part is equal to or greater than a prescribed voltage.

Abstract: A recreational vehicle includes a chassis having a living space, an electrical system for providing electrical power to the living space, an air conditioner for cooling the living space, a heater for heating the living space, and a plurality of appliances within the living space attached to the electrical system. The recreational vehicle also includes an engine for moving the recreational vehicle, a motor generator for supplying power to the recreational vehicle, a connector for connecting the electrical system of the recreational vehicle to an external power source, and a local area network system electrically connected to the air conditioner, the heater, the plurality of appliances, and the motor generator. The local area network manages the power provided to the to the electrical appliances. A display positioned within the living space shows data related to the air conditioner, the heater, the plurality of appliances, the motor generator and the engine.

Abstract: A high-voltage energy regulated conversion circuit (HVERCC) (12) for electrically coupling to a vehicle bus (24) is provided. The HVERCC (12) includes a high-voltage energy converter (HVEC) module (22) coupled to the vehicle bus (24), a battery-pack high-voltage bus battery bus (28), and a WEG heater bus (29). The battery bus (28) is coupled to a high-voltage battery pack (30) and a WEG heater circuit (32). The HVEC module (22), the high-voltage battery pack (30), and the WEG heater circuit (32) are coupled to a logic controller (14) via a network (36). The logic controller (14) regulates the power on the vehicle bus (24), the battery bus (28), and the WEG heater bus (29). An operational method for the HVEC module (22) is also provided.

Abstract: An electronic component formed as a regulator for generators in motor vehicles has an IC block arranged on a cooling body, connectors provided with conductors, bond wire connectors connecting the IC block with the conductors, the conductors being provided at first ends which face the IC block with a first bond pad, forming a limited free space behind the first bond pad as seen from the IC block for insertion and withdrawal of a bond tool, the conductors of the plug connectors being each provided with a second bond pad located behind the limited free space at a distance from the first bond pad, for further bond wire connections of at least one selectively useable electronic component.

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.

Abstract: Method for detecting a signal, particularly a voltage, for example a battery voltage, having the following steps: measuring the signal and/or the battery voltage at a predefined sampling rate, storing the measured measurement values in a buffer memory, and forming a median value of the stored measurement values in a time-slot pattern slower than the sampling rate to obtain an averaged value.

Abstract: A slowly rotating synchronous generator (ring generator) for a wind power installation, the generator having a rotor and a stator surrounding the rotor, and the stator having at least one three-phase current winding on which a capacitive current is impressed, and the generator having a part of the exciter power of the generator produced by the stator.

Abstract: A voltage control apparatus 1 for a vehicle generator 2 has an input terminal L for inputting the voltage of a battery 5 through an ignition switch 3 and a light emitting element (light emitting diode 4) connected in series with the ignition switch and driven by a low dissipation power, and starts the excitation of the rotor coil 201 of the vehicle generator 2 when the voltage at the input terminal L exceeds a predetermined value. A resistor 115 for limiting the current flowing through the light emitting diode 4 is disposed between an element 114 within the voltage control apparatus 1 for driving the light emitting diode 4 and the input terminal L.

Abstract: A generating device including a magneto generator, wherein: an AC control voltage is applied to an armature coil of the magneto generator from a battery via an inverter to change a phase angle of the AC control voltage, thus increase/reduce an output of the magneto generator and match the output of the generator with a target value; it is determined that a characteristic, in which the output of the magneto generator increases when the phase angle of the AC control voltage is delayed, is a normal control characteristic, and a characteristic, in which the output of the magneto generator decreases when the phase angle of the AC control voltage is delayed, is a reciprocal control characteristic; and it is determined whether a present control characteristic of the output of the generator relative to the phase angle of the AC control voltage is the normal control characteristic or the reciprocal control characteristic to decide, based on a determination result, a changing direction of the phase angle of the AC cont

Abstract: A plurality of control power sources of voltage specifications different from one another are constructed. A generator output converted by a converter into a DC current is converted by an inverter into an AC current of a predetermined frequency. The generation output is rectified by second rectifier circuits and a capacitor and is then input to an RCC. The RCC constitutes a self-excited oscillation circuit, energy is stored into a transformer in an ON time of a transistor corresponding to an oscillation frequency thereof, and the energy is transferred to a secondary side in an OFF time. In the secondary side of the RCC, windings are formed corresponding to the number of required power sources. One group of windings forms both positive and negative power sources of a control power source, and another group of windings forms a power source for an FET driver.

Abstract: In a vehicle generator control which detects an abnormal operating condition of a generator of a vehicle, and includes a transistor which drives a charging lamp to emit a warning indication when such a condition is detected, with the value of a quantity indicative of the flow of current through the charging lamp drive transistor being compared with a reference value, and with the transistor being set in a non-conducting state if the reference value is exceeded, a succession of respectively decreasing reference values is periodically generated. A timing of an initial flow of current through the charging lamp is controlled to be synchronized with the start of such a succession, so that the peak value of an initial surge current which flows through the charging lamp drive transistor is compared with the highest reference value. Complete protection can thereby be established for the charging lamp drive transistor against a flow of short-circuit current which would exceed any of the reference values.

Abstract: A method and apparatus of stator voltage control for an induction generator. Each phase of the induction generator stator is connected through a secondary coil of a transformer to a utility grid. A stator voltage control circuit is connected in parallel with a primary coil of the transformer. The stator voltage control circuit consists of an on/off switch device connected to a full wave rectifier comprised of four silicon diodes. A single pulse width modulation (PWM) control is utilized to control the on/off switch devices of each phase of the induction generator stator.

Abstract: A portable power source (10) includes a housing (12), a stator component (20), a rotor component (18), a crank assembly (14), and a control system (24). The stator component (20) is secured to the housing (12), the rotor component (18) rotates relative to the stator component (20) and the crank assembly (14) is coupled to the rotor component (18). The crank assembly (14) is rotated by the user relative to the housing (12). As provided herein, rotation of the crank assembly (14) by the user results in rotation of the rotor component (18) relative to the stator component (20). In one embodiment, the control system (24) controls the amount of torque required to rotate the crank assembly (14). For example, the amount of torque required to rotate the crank assembly (14) is varied according to the rotational position of the crank assembly (14).

Abstract: A device and a method for the control of a generator, for example a claw-pole generator, with which the rectifier bridge connected to the generator can be temporarily short-circuited, as a result of which power is temporarily stored in the stator inductors, which results in higher phase voltages. Suitable selection of the control frequency for a transistor, which makes the short-circuiting of the diode bridge possible, allows an output voltage of the generator to be set to the desired voltage level which is clearly higher than the conventional vehicle electrical system voltage. The diode bridge itself can be replaced by controllable switching elements (transistors) and a voltage adjustment is implemented using suitable controls.

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.

Abstract: A control system regulates power to a brushless synchronous generator (BSG) (204) having a permanent magnetic generator (PMG)(210), an exciter (208) and a main generator (206) connected to a rotating shaft (212). The generator control unit (GCU) (202) includes a three phase rectifier (214), a PMG voltage regulator (222), a generator control relay (GCR)(220), a GCU power supply (216) with a backup power source (217), a field switch driver (218), a field switch (219), and a free wheeling diode (221). The BSG (204) is connected to the GCU (202) by coupling the PMG (210) of the BSG (204) to the three phase rectifier (214) of the GCU (202) and by coupling the exciter (208) of the BSG (204) to the PMG voltage regulator (222) and the field switch driver (218) of the GCU (202) and the PMG voltage regulator (222) regulates the voltage of the PMG (210).

Abstract: A vehicle power generation control apparatus that has a power supply circuit, a rotation detecting circuit, an exciting current detecting circuit, an exciting current control circuit, a torque detecting/maximum exciting current determining circuit and a power transistor. When a speed of rotation of a vehicle generator is detected by the rotation detecting circuit and an exciting current flowing through an exciting winding of the vehicle generator is detected by the exciting current detecting circuit, the torque detecting/maximum exciting current determining circuit calculates an upper limit value of the exciting current so that a rate of change of a generator torque does not exceed a predetermined value, and the exciting current control circuit controls the exciting current so that the exciting current becomes below the limit value. This can prevent the engine revolution from becoming unstable due to variation of load or variation of engine revolution.

Abstract: An engine start/stop control system for preventing an engine from stopping when a vehicle is traveling. The system includes an IG1 driver circuit arranged between a power supply control unit and an IG1 relay. The IG1 driver circuit is activated in accordance with an activation signal from the power supply control unit or an output signal of a latch circuit and includes an FET for activating a relay. The latch circuit keeps the FET ON and the relay activated unless the vehicle stops traveling and a start/stop switch is pushed.

Abstract: A generator field regulator circuit communicates with a field winding of a Lundell machine and includes a first transistor. A second transistor has a source that communicates with a drain of the first transistor and a drain that communicates with one end of the field winding. A free-wheeling diode communicates with the drain of the first transistor and a source of the second transistor. An overvoltage detection circuit modulates a gate of the second transistor. A pulse width modulation (PWM) circuit modulates a gate of the first transistor to maintain generator rectified voltage at a nominal level. The overvoltage detection circuit outputs an overvoltage shutdown signal to the PWM circuit during a full-load dump mode to turn off the first transistor, which turns off the second transistor. The overvoltage shutdown signal is disabled when a terminal voltage of a generator falls below a predetermined voltage.

Abstract: An energy generator using transistors to amplify current and use some of its energy to prolong the life of its battery.

Abstract: A wound field synchronous machine control system comprises: an auxiliary winding for obtaining auxiliary AC voltage from the wound field synchronous machine; a phase controlled rectifier for rectifying the auxiliary AC voltage and supplying rectified DC voltage to the wound field synchronous machine; and a controller. The controller is configured for using a voltage signal across the auxiliary winding to obtain volt-second values of the auxiliary winding and using the volt-second values for firing angle control of switches of the phase controlled rectifier. Alternatively or additionally, the controller is configured for obtaining airgap flux values of the wound field synchronous machine and using the airgap flux values for firing angle control of switches of the phase controlled rectifier.

Abstract: A rotary electric machine having a plurality of rotors is driven by a compound current. A voltage to be applied to a stator of the rotary electric machine is in the form of a compound rectangular or stepwise voltage composed of a plurality of superposed components each of which is a rectangular or stepwise wave having a frequency corresponding to the revolution speed of a unique one of the rotors.

Abstract: An abnormality detection apparatus of a vehicle AC generator that includes a rectifier for providing DC voltage is disclosed. The abnormality detection apparatus includes an abnormality judging unit and an alarm lamp. The abnormality judging unit judges abnormality of the vehicle AC generator if the number of ripples that is included in the output voltage of a rectifier is not equal to or more than a predetermined number for a predetermined period. The alarm lamp lights when the abnormality judging unit judges abnormality.

Abstract: A system and method for electrically coupling windings of a main generator rotor to a plurality of DC sources on an exciter that each have respective first-voltage and second-voltage terminals is disclosed. The system includes first and second conductive plates supported by the rotor that respectively define first and second apertures that surround a rotor shaft. The first plate includes a first rotor winding terminal by which the plate is electrically coupled to the windings, and a first plurality of terminals configured to be respectively coupled to the first-voltage terminals of the DC sources. The second plate is electrically insulated from the first plate, includes a second rotor winding terminal by which the second plate is electrically coupled to the windings, and includes a second plurality of terminals configured to be respectively coupled to the second-voltage terminals of the DC sources.

Abstract: A wound field synchronous machine control system comprises: an auxiliary winding for obtaining auxiliary AC voltage from the wound field synchronous machine; a phase controlled rectifier for rectifying the auxiliary AC voltage and supplying rectified DC voltage to the wound field synchronous machine; and a controller. The controller is configured for using a voltage signal across the auxiliary winding to obtain volt-second values of the auxiliary winding and using the volt-second values for firing angle control of switches of the phase controlled rectifier. Alternatively or additionally, the controller is configured for obtaining airgap flux values of the wound field synchronous machine and using the airgap flux values for firing angle control of switches of the phase controlled rectifier.

Abstract: A control unit of a vehicle generator is provided which is capable of instantaneously stopping power generation in a safe manner with an inexpensive system configuration without the need of interrupting a large current when a key switch is turned off. The control unit includes a vehicle generator (2), a battery (5) adapted to be charged by an output of the vehicle generator, and a control circuit (2) having an on-off control switching transistor (1j) for controlling the turning on and off of a field current of the vehicle generator. The control circuit is operable to interrupt the on-off control switching transistor (1j) when a detected voltage of the battery (5) is higher than a reference voltage, and make the on-off control switching transistor (1j) conductive thereby to control the voltage of power generation at a predetermined voltage when the detected voltage of the battery (5) is below the reference voltage.

Abstract: An excessive voltage protection system for a variable frequency generating system detects single point failures in a generator control unit and prevents excessive voltages at a point of regulation (POR) in the system. The generator control unit is designed to detect failures, such as a loss of three-phase sensing capability, switch failure in the exciter drive circuit, and/or exciter current loop failure. If a failure occurs, the generator control unit stops operation of the exciter drive circuit, preventing the voltage at the POR from rising to undesirable levels.

Abstract: An excitation controller controls excitation of a synchronous machine, which is connected to a power transmission system through a transformer, so that a high-side voltage of the transformer is maintained at a target voltage with high accuracy. An output terminal target voltage of the synchronous machine is set to precisely compensate for a voltage drop in the transformer, corresponding to the transformer phase angle variation. To achieve this result, the excitation controller detects an output terminal voltage and an output current of the synchronous machine and calculates active and reactive currents of the output current, sets the output terminal target voltage of the synchronous machine from the active and reactive currents, the high-side voltage of the transformer, and the reactance of the transformer, and controls excitation of the synchronous machine to compensate for the voltage drop in the transformer corresponding to phase angle variation of the transformer.

Abstract: An electrical power distribution system includes permanent magnet generator, and an ac regulator. The ac regulator includes an inverter shunt-connected to the permanent magnet generator, and an inverter control for causing the inverter to regulate voltage at output terminals of the generator by providing reactive power (either leading or lagging) that circulates between the inverter and the generator.

Abstract: A regulating device for regulating the output voltage of a generator; in particular a vehicle generator is described. To improve protection of the voltage regulation from failure, for normal operation it is proposed to perform the regulation using a main regulator which is implemented as software in a control unit, and in the event of a malfunction of the main regulator, to perform the regulation using an auxiliary regulator.

Abstract: A loop-type voltage regulating device, particularly for regulating a voltage of an automotive electric system that includes at least one thermal engine, a voltage regulator and an alternator operative to deliver a system regulated-voltage signal to and receive a regulation signal from the voltage regulator, the voltage regulating device including a control unit within the regulating loop, which unit is connected between the thermal engine and the voltage regulator and is adapted to supply the latter with a signal related to the engine operation.

Abstract: Disclosed are a flux observer and a sensorless control system of a synchronous reluctance motor. The flux observer includes an estimated flux output unit, a measured flux output unit, and a fixed/rotational coordinate converter. The flux observer estimates a flux of a synchronous reluctance motor by removing higher harmonic components of a current in a rotational coordinate system which flows into the motor. The measured flux output unit measures a flux in a fixed coordinate system by combining a voltage in the fixed coordinate system, which is applied to the motor, and a current in the fixed coordinate system, from which higher harmonic components are removed, with the estimated flux outputted from the estimated flux output unit. The fixed/rotational coordinate converter converts the measured flux outputted from the measured flux output unit to a measured flux in the rotational coordinate system.

Abstract: An automotive alternator is provided which includes a rectifier, a circulating circuit, and a controller. The circulating circuit is connected in parallel to a field winding to circulate the field current in the event that supply of the field current to a field winding is cut. The circulating circuit consists of a first circuit formed by a diode and a second circuit working to enhance attenuation of the field current. The controller works to select the second circuit when a voltage of the output of the rectifier exceeds a reference value and select the first circuit when the voltage of the output of the rectifier is less than the reference value.

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.

Abstract: In an alternator, failure in a power supply line connected to an output terminal of a rectifier is detected. Upon detection of a failure in this power supply line, power generation is suppressed for a predetermined period that is longer than the time constant of a field winding of the alternator. Preferably, a high voltage pulse is detected to discriminate a first condition where a single high voltage pulse is generated when an electrical load connected to the power supply line is cut off and a second condition where a high voltage pulse is repeatedly and frequently generated when a failure occurs in the power supply line. Only when the second condition is discriminated, power generation suppression control of the alternator is conducted.

Abstract: A voltage regulator for an a.c. generator produces a power generation ratio signal having a duty ratio corresponding to the current supply to the field winding of the a.c. generator. This power generation ratio signal is applied to an external apparatus through a signal wire. The duty ratio of the power generation ratio signal is more than 10% when the a.c. generator is normal. When abnormality is detected, the power generation ratio signal is partly masked by an abnormality detection signal so that the duty ratio of the power generation signal is reduced to be less than 10% and this change may be detected by the external apparatus. Alternatively, the power generation ratio signal may be transmitted only intermittently when the abnormality is detected.

Abstract: A controller for an alternator driven by an output torque of an automotive engine mechanically through a belt is provided. The controller works to control an exciting current supplied to a field winding of the alternator so as to cancel a change in inertia torque of a rotor of the alternator arising from a change in speed of the engine, thereby minimizing a change in tension of the belt.

Abstract: In an automobile electrical system having an alternator drivingly connected to a vehicle engine the alternator has a polyphase output winding producing a polyphase output in the form of a polyphase alternator voltage for each phase. A load dump apparatus and method for varying the output of the alternator employs a bridge coupled to the polyphase output winding and having a pair of direct voltage output terminals. The bridge has lower and upper switchable elements for each corresponding phase winding, the switchable elements are forward biased and connected in series across the output of the bridge and have a common or neutral input note connected to the corresponding phase winding. Each switchable element is controllable in accordance with a respective conduction signal applied thereto.

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.

Abstract: A voltage regulator is part of a vehicle charging system having an alternator or generator and field winding and connected to a vehicle battery and devices for supplying a voltage and powering vehicle devices. The voltage regulator includes a microcontroller operative for monitoring output voltages representative of monitored load changes within the vehicle. A power output circuit is operatively connected to the microcontroller and connects to a field winding. The microcontroller is operative for changing the field duty cycle of the generator or alternator by turning ON and OFF the power output circuit in a predetermined manner as established by the microcontroller based on monitored load changes.

Abstract: An electric power generating set which automatically varies its speed to match load variations at any time includes an engine driven generator G which provides a positive, Ga and a negative, Gb AC output voltage each of which is rectified by a respective rectifier Re3a, Re3b. Each rectifier Re3a,Re3b has one terminal connected to a common neutral line N. The DC output voltage of each rectifier Re3a, Re3b is boosted in a respective booster circuit which also has one terminal connected to the neutral line N. The combined output of the two booster circuits, Va+Vb is fed to an Inverter IN which converts it to the AC power output of the generating set. A DC load current between the booster circuits and the inverter IN is monitored and used to provide a speed demand feedback signal Srs to the speed control of the engine EN.

Abstract: An alternator for a motor vehicle comprises an excitation regulator circuit comprising a controlled switch (Tex) in series with the excitation winding, and a freewheel component (DL) which is connected to the terminals of the winding, and a circuit (10, 20, 30) for delivering information (Is1; Is2) representative of the state of excitation (Iexc) of the alternator. According to the invention, this circuit comprises: a means (10) for generating, while the switch is in the on state, a first signal (U1) proportional to the current (Iex) flowing through it; and a means (20) for generating a second signal (U2), this means being capable, while the switch is on, of generating the second signal on the basis of the first signal and, while the switch is off, of generating the second signal by storing (CD) the first signal which existed before the said switch was turned off.

Abstract: In an alternator, failure in a power supply line connected to an output terminal of a rectifier is detected. Upon detection of a failure in this power supply line, power generation is suppressed for a predetermined period that is longer than the time constant of a field winding of the alternator. Preferably, a high voltage pulse is detected to discriminate a first condition where a single high voltage pulse is generated when an electrical load connected to the power supply line is cut off and a second condition where a high voltage pulse is repeatedly and frequently generated when a failure occurs in the power supply line. Only when the second condition is discriminated, power generation suppression control of the alternator is conducted.