Showing papers on "Rectifier published in 1977"

High power factor conversion circuitry

Abstract: A high power factor conversion circuit suitable as a ballast circuit for lamps includes a full-wave rectifier coupled to an AC potential source and providing a pulsating DC potential. A high frequency inverter is coupled to a load circuit and to a feedback rectifier circuit supplying a rectified high frequency potential to an energy storage feedback circuit which provides energy in a manner to inhibit a decline in the pulsating DC potential thereby providing a substantially uniform DC potential to the high frequency inverter.

Load balancing system for ups rectifiers

Abstract: In order to maintain a balanced load between power rectifiers operating in parallel within an uninterruptible power system, individual closed loops are established for regulating the direct current voltage at the output of the rectifiers and an open loop generates a reference voltage for each of such regulations. An operational amplifier is used as a current source to develop a current representative of the load in a particular rectifier. Parallel current dissipating resistors between each rectifier line and a floating potential common to all rectifier lines generates a reference voltage which is proportional to the average of such current dissipations and represents the average rectifier load.

Alternator having improved rectifier cooling

Abstract: The rectifier assembly of an alternator is provided with improved cooling by improved air flow directed over the semiconductor elements of the rectifier assembly. Improved flow of air is provided by an auxiliary fan blade that is attached to a rotating member in the alternator structure. The fan blade is in proximity to the semiconductor rectifier elements of the rectifier assembly. Air ports are provided in the alternator housing to accommodate this air flow and to improve the distribution of cooling air.

Protection arrangement for a brushless synchronous machine

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.

Device for melting the icing by direct current on conductors of overhead power transmission line

Abstract: The device for melting the icing by direct current through conductors of an overhead power transmission line comprises a rectifier coupled during the ice melting period by its lead-out wires to the disconnected conductor of the power transmission line, a ground wire, and a current filter set in resonance to the line at the commercial frequency, which is, for example, a capacitor bank connected in series to a reactor, whose lead-out wires are connected in parallel to the direct-current voltage lead-out wires of said rectifier. This device can be used to melt the icing by direct current through conductors and cables of overhead power transmission lines within a voltage range from 110 to 220 kv and more.

Control logic for a phase controlled rectifier system

Abstract: Apparatus for providing firing signals to a phase controlled rectifier circuit at a time at which valves in the rectifier circuit are forward biased without the need for providing continuous firing signals. The apparatus monitors the voltage applied across the rectifier valves and provides a signal when a valve is forward biased. This signal is applid to a gating circuit which determines whether a normal phase control firing command was initiated prior to the time the valve became forward biased. If such a command was initiated, the gating circuit passes the signal to a valve firing circuit which provides firing signals to the rectifier circuit. If the firing command was not previously initiated, the signal is inhibited and firing signals are subsequently applied to the rectifier circuit upon receipt of a firing command.

The Vacuum-Insulated, Varying-Capacitance Machine

Abstract: The prospects for a varying-capacitance, vacuum-insulated, rotating machine have been examined analytically for the generation of HVDC power. Such a machine offers two potential advantages over conventional rotating machinery: 1. It is capable of very high efficiency (losses in the machine itself - excluding diodes or thyristors which might be necessary in some applications - would be less than 0.1%). 2. It is inherently suitable to high voltage operation. It appears that these machines, utilizing the best present-day techniques, are not an advantageous alternative to conventional magnetic synchronous machines for power frequency applications. For the generation of HVDC power, however, the situation is quite different: the vacuum-insulated, varying- capacitance machine would be comparable in size to the conventional magnetic machine and would possess the important advantages of producing HVDC power directly, and with higher efficiency. Assuming that 10 kV/mm could be insulated across the rotor-to-stator gap, such an HVDC machine would be 30-50% larger than a conventional synchronous alternator, but would, in effect, replace not only the alternator, but the power transformer and rectifying equipment. Losses in the vacuum-insulated HVDC machine would be 1/3 the losses of the conventional alternator-transformer -rectifier combination. If gradients of 25 kV/mm could be supported in the vacuum-insulated machine, it would be 20-30% smaller than the conventional alternative of a combination of magnetic synchronous machine, high voltage transformer, and rectifier. The design of a 7,000 kW,200 kV, dc generator, based on peak working gradients of 25 kV/mm, is discussed as an example.

Control system for a tertiary winding self-excited generator

Abstract: A control system for a self-excited alternator which includes an auxiliary winding adapted to supply excitation to the alternator field winding incorporates a circuit for supplementing field excitation when the available energy from the auxiliary winding is less than the desired magnitude of field excitation. The self-exciting a-c current from the auxiliary winding is coupled through a phase-controlled rectifier circuit to the alternator field winding. A secondary excitation source such as a battery is coupled to the alternator field winding through a chopper circuit. A regulating circuit is responsive to a field current reference signal for controlling the conduction of the phase controlled rectifier circuit and the chopper circuit in a manner to regulate the alternator field excitation to the desired value. The regulating circuit is adapted to supplement the excitation supplied by the auxiliary winding with excitation from the secondary source until the excitation available from the auxiliary winding is sufficient to supply the desired magnitude of alternator field excitation.

Spark plug igniter comprising a dc-dc converter

Abstract: A spark plug igniter with an auxiliary power source, in which the auxiliary power source is a DC-DC converter including a feedback loop. A high voltage induced in a secondary winding of an ignition coil and a DC voltage generated by the converter are additionally supplied in the same polarity to a spark discharge gap. The feedback loop of the DC-DC converter comprises a feedback winding, a rectifier connected to the feedback winding through a reactance element, and means for connecting the DC output of the rectifier in series to the DC power source of the converter in the same polarity.

Power supply circuit

Abstract: PROBLEM TO BE SOLVED: To obtain a power supply circuit comprising a switching converter and arranged to deliver a DC output voltage as the power supply voltage in which ripple current of a smoothing capacitor is suppressed. SOLUTION: As the basic circuitry, a pair of two sets of transformers PIT-1 and PIT-2 is connected in parallel with the switching output from a primary current resonance converter and a full-wave rectifier circuit is formed on the secondary of each transformer PIT-1, PIT-2. A smoothing capacitor Co is employed commonly in two full-wave rectifier circuits and connected such that the rectified current from each full-wave rectifier circuit flows into the smoothing capacitor Co. Under such circuitry, each primary winding Np of the transformer PIT-1, PIT-2 is connected in parallel with the switching circuit of a switching element Q1, Q2 such that the polarity is reversed. COPYRIGHT: (C)2004,JPO&NCIPI

Power supply circuit

Abstract: In a power supply circuit of the type including a first rectifier to be connected to an AC power source through a power switch, a transformer with primary and secondary windings, a second rectifier connected to the secondary winding of the transformer to provide a desired DC output voltage, a pulse width modulated signal producing circuit, and a transistor connected to the primary winding of the transformer to be supplied with the pulse width modulated signal so as to chop the direct current flowing through the transformer; there is further provided an oscillation circuit connected to the primary winding of the transformer for generating an oscillation signal for a predetermined period following closing of the power switch, and a third rectifier for producing a DC voltage in response to such oscillation signal, with the DC voltage from the third rectifier being supplied to the pulse width modulated signal producing circuit as an operating voltage therefor

Dual output battery charging system

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.

Power control unit for a single phase load with slightly changing impedances

Abstract: There is disclosed herein a power control unti for controlling the voltage and power delivered to a single phase load, said control unit being preferably employed with loads whose impedance changes but slightly over the work cycle. The circuit utilizes a diode rectifier and a controlled rectifier connected in parallel therewith connected in series with capacitance and achieves transient-free and harmonic-free power control.

Circuit for energizing a fuel injector valve coil

Abstract: A circuit for energizing a fuel injector valve coil in response to a fuel injection pulse including a storage capacitor which is charged from a relatively high voltage source and which is discharged through the fuel injector valve coil through a controlled rectifier gated conductive upon the initiation of a fuel injection pulse signal. The charging circuit for the capacitor is disabled upon initiation of capacitor discharge for a time period at least greater than the time for the capacitor discharge current to decrease to a value to effect commutation of the controlled rectifier after which capacitor charging is reinitiated. A holding circuit is provided for holding the fuel injector valve coil energized for the duration of the fuel injection pulse signal.

Battery charging systems for road vehicles

Abstract: A battery charging system includes an alternator, a main rectifier for charging the battery, and an auxiliary rectifier for supplying current to the alternator field winding under control of its voltage regulator 20 A first transistor switch is sensitive to under voltage to illuminate a first warning light and a second transistor switch is sensitive to over voltage to illuminate a second warning light The two transistor switches are cross-connected so that failure of either light causes illumination of the other

Application of Power Capacitors to Electrochemical Rectifier Systems

Abstract: The increasing awareness of the value of energy has caused an increase in the usage of power capacitors on electric power systems serving electrochemical rectifiers. An understanding of the characteristics of large rectifier systems is essential to the successful application of capacitors. The influence of rectifier harmonic currents on capacitor duty and how the interaction of the capacitor and the supply system can amplify this duty are discussed.

Zero voltage switching solid state relay

Abstract: A solid state relay or controlled switch for connecting an AC power source to a load includes a solid state switching circuit in which a semiconductor controlled rectifier element, such as a photothyristor, thyristor or light-AC controlled element, is ignited by an external control signal, thereby to feed a load with an alternating current. A zero voltage switching circuit which executes switching when the instantaneous value of the amplitude of the supply voltage of the AC load current is zero or a value close thereto is connected to the rectifier element. As an improvement, a series circuit consisting of a resistor and a capacitor are connected between the base and emitter of a transistor in the zero voltage switching circuit. Thus, a zero voltage switching solid state relay whose withstand voltage build-up rate is enhanced and whose switching is endowed with a hysteresis characteristic is provided.

Drive circuit for solenoid pump

Abstract: A drive circuit for a solenoid pump comprises a series combination of a pump solenoid and a capacitor connected through a rectifier circuit with an a.c. source. The solenoid is shunted by another rectifier poled to pass a charging current to the capacitor. A thyristor is connected across the series combination, and is triggered into conduction, whereupon it short-circuits the series combination to permit a discharge of the capacitor through the solenoid and to prevent a current flow from the source to the capacitor, thus allowing a uniform control of the energy discharged by the capacitor. A trigger circuit for the thyristor comprises a relaxation oscillator including a programmable unijunction transistor, the conduction of which is controlled inversely to fluctuations in the source voltage.

Apparatus for indicating the loading of an electric ac motor

Abstract: An apparatus for providing a signal the magnitude of which indicates the loading of an AC motor. Two pairs of antiparallel-connected diodes generate two AC signals of constant amplitude and of fixed phase position relative to the motor current and the motor voltage, respectively. A load indicating signal is obtained by means of a phase comparator to which these two signals are supplied. A rectifier circuit produces a direct voltage proportional to the supply voltage of the motor, and the direct voltage is combined with the output signal of the phase comparator to compensate for variations in the output signal, which depend upon variations of the supply voltage.

Rectifier unit for provision in an alternator

Abstract: A cooling plate of the unit is connected to each of the a.c. terminals of the alternator and each cooling plate carries the positive-side diode or diodes, the negative-side diode or diodes and the excitor field diode connected to that a.c. terminal. The cooling plates are mounted on a shaped insulating disk in which wires are embedded for connecting together the connection leads of the diodes. Provision is made for bringing out terminals for the connection of a regulator unit and for bringing out a terminal for one a.c. phase, as well as for attachment of the d.c. output terminals.

Dual voltage automotive on-board electrical network system

Abstract: To simplify connection of a starter motor to a 24V supply with a normal on-board network of 12V, an auxiliary rectifier and an auxiliary battery are connected in parallel to the output of an automotive alternator. The starter relay switch contacts are so arranged that, only upon operation of the starter switch, the two batteries are connected in series and then to the starter motor. The supply connections to the batteries are left undisturbed, feedback being prevented by the rectifiers which are connected to the output of the alternator.

Condition responsive thermostat control apparatus

Abstract: An ambient room illumination responsive control automatically changes the setting of a thermostat with ambient illumination. A thermostat has a pair of temperature responsive switches connected in series with control leads and a controller to low voltage A.C. power. A bypass relay has contacts connected in parallel with one of said switches. An illuminating sensor has a photoresistor in series with a resistor connected across leads with a common node connected to the gate of a controller rectifier. A capacitor timing unit is connected in one embodiment to produce a pulsed input. The rectifier is connected in series with a winding of the bypass relay and the timing unit across the thermostat leads. The rectifier conducts to open the relay contacts and insert the second switch in circuit. A second relay winding is connected across the control leads in series with a diode and a timing network to reset the relay and close the contacts. The time constants of the two timing circuits where employed insure proper operation of the set and reset branch circuits. A separate remote pulse control may be provided.

Gas discharge flash lamp with piezoelectric trigger generator

Abstract: An electronic flash unit for igniting a gas discharge flash lamp by means of a piezoelectric element. The unit input terminals are interconnected by a series circuit comprising a rectifier and an undercritically damped parallel LC circuit. The lamp starting electrode is coupled to one main electrode via the inductor (L) and exclusive of the rectifier. The unit produces a lamp ignition signal consisting of a pulse train of alternating polarity which provides more reliable ignition of the flash lamp.

Solid state switch

Abstract: A solid state switch is provided which has four terminals, two for the A.C. power which is to be switched and two for signal input. The circuit comprises a full wave bridge rectifier having a light-activated silicon controlled rectifier connected across its D.C. terminals. A capacitor and a light-activated transistor are added to a zero-cross firing circuit whereby the solid state switch is protected from high voltage transients and is applicable for use with resistive, capacitive, and inductive loads.

Electrical power supply fault detecting system

Abstract: To detect system ground faults and shorted alternator output winding turn-to-turn faults, the series combination of a resistor and the operating coil of an electrical relay having a normally closed contact pair is connected between the neutrals of two parallel connected polyphase alternator output winding groups, the junction between the resistor and operating coil is connected through a resistor to ground and the normally closed relay contact pair is connected in series in the alternator exciting field winding energizing circuit. To detect open diodes in the main polyphase diode bridge type full-wave rectifier circuit, an auxiliary polyphase full-wave rectifier circuit having the operating coil and normally closed contacts of two relays in series in each leg is provided. Upon the failure of a diode of the main rectifier circuit, sufficient current to operate the corresponding relay in the auxiliary rectifier circuit is diverted therethrough. Upon the operation of one of the auxiliary rectifier circuit relays, the magnitude of the energizing potential supplied to the alternator exciting field winding is reduced and upon the operation of more than one of the auxiliary rectifier circuit relays, the alternator exciting field winding energizing circuit is interrupted.

Demand controlled preregulating rectifier circuit for power supplies

Abstract: A rectifier and preregulator circuit using a first silicon controlled rectifier (SCR) to rectify AC voltage and apply the rectified voltage across a capacitor which is used as a storage device. The circuit also includes a transistor, zener diode and a second (SCR) in a switching arrangement for turning on the first SCR and for turning off the transistor and zener diode when a minimum voltage is reached so as to minimize dissipation of electrical power in the circuit. A second zener diode and a third SCR are used in a switching arrangement to control the maximum rectified voltage from the circuit.

Two-wire proximity detector

Abstract: In a two-wire proximity detector, a supply to a probe and auxiliary apparatus is obtained from a bridge rectifier through two regulating circuits of which the first operates when an inhibitor transistor is conducting, while the second operates when the inhibitor transistor is blocked. The first regulating circuit is of the ballast type. The second regulator circuit is of the type which produces a delay in the triggering of a switch thyristor (9). The detector can be fed with an alternating voltage variable over a wide range.

Loudspeaker overload circuit

Abstract: An overload circuit for a loudspeaker system which indicates the overload and also automatically reduces the load on the speaker system to prevent damage in which a rectifier followed by a smoothing circuit is connected in parallel with the speaker and supplies an output to a magnetic coil for energizing a magnetic switch on overload so as to place a load dropping means in series with the speaker during overload The load dropping means might be a lamp which visually indicates the overload condition

Power control circuit

Abstract: A circuit for controlling the power delivered to a load from an alternating current source includes a bridge rectifier coupled to the alternating current source for developing full and half-wave rectified signals in response thereto. The full and half-wave rectified signals are algebraically added to form a reference signal which is applied to one input of a comparator, the other input comprising an adjustable direct current control signal. The output of the comparator comprises a pulse width modulated signal which is used to control the state of a switching transistor connected in series with the load between the rectifier node developing the full-wave rectified signal and a point of reference potential.

Electrical generating system, particularly for automotive use

Abstract: To prevent unusually high or low voltage output from an automotive-type alternator, in case of failure of connection from the alternator rectifier output to the automotive vehicle battery, a connecting network is provided connecting an auxiliary alternator output terminal to the voltage sensing circuit to control the voltage sensing circuit to in turn control the field current to the alternator to prevent excessive output voltages. Additionally, a further voltage sensing circuit is connected to the auxiliary terminal to provide limited energization to the field for self-excitation of the generator if the vehicle engine, driving the generator is started, for subsequent transfer of control to the main voltage sensing circuit, but to prevent continuous field current flow at full field current value to prevent burnout of the field in case the engine is not started, but the main vehicle switch, typically the ignition switch, is left closed.