Showing papers on "Rectifier published in 1968"

Effect of High-Speed Rectifier Excitation Systems on Generator Stability Limits

Abstract: A device to provide a signal proportional to changes in generator speed has been developed by Ontario Hydro. Field tests have been performed to demonstrate that use of this signal with a high-speed rectifier excitation system results in dynamic stability limits which approximate those which can be obtained with a zero reactance generator. Transient stability limits are greater than those obtainable with high-response conventional excitation systems. Results from the field tests and a computer study are compared.

Automatic battery charging control device and apparatus

Abstract: An automatic battery control system for vehicles and the like, having a main battery used for motor starting and one or more auxiliary batteries, and wherein each of such batteries is connected to a diode or rectifier, and wherein the two or more diodes or rectifiers are connected to a common terminal which is connected to a generator, whereby the main and auxiliary batteries may be discharged independently of each other at their respective loads, and may be charged automatically from the common generator source, with the diodes or rectifiers preventing the batteries from discharging back through the common terminal.

High frequency power supply

Abstract: A static, single-phase, alternating current supply for powering an inductive load In a preferred embodiment, the load is an induction heating coil with parallel power factor correcting capacitors, but equivalent elements consisting of parallel connected inductance and capacitance may be incorporated in the system and any external load can then be powered Adjustment of output power and/or voltage is accomplished by varying the frequency of the supply The preferred embodiment includes an alternating current input of line voltage and frequency, a rectifier producing DC output voltage of substantially constant magnitude, an inverter capable of operation over a range of frequencies for converting the DC voltage to high frequency alternating current, and inductive reactance between the inverter and the load The frequency of the inverter is controlled by an oscillator which has various inputs providing control functions

High-frequency lamp operating circuit

Abstract: Circuit operating from a low-voltage current source for applying high-voltage, high-frequency alternating current to a load such as a gaseous discharge lamp connected across the source includes a charging capacitor and a first induction coil connected across the source and forming a first resonant circuit, a second induction coil and a controlled rectifier switch connected in series across the capacitor forming a second resonant circuit when the controlled rectifier switch is closed, and triggering means connected to the source for operating the controlled rectifier switch in accordance with a predetermined rate, the second resonant circuit operating to close the controlled rectifier switch, and the first resonant circuit operating when the switch is opened to raise the voltage and apply it to the load in high-frequency pulses for starting and operating the same.

Power generating unit for railway coaches

Abstract: A power-generating unit for railway coaches which comprises a synchronous electrical machine connected to the coach circuits through a rectifier.

Comparison of Computer and Test Results of a Static AC Drive System

Abstract: The effectiveness of an analog computer (electronic differential analyzer) in studying the performance of a rectifier-inverter-induction motor drive system is demonstrated. Computer diagrams are not given. However, methods of simulating the system components sufficient to describe their dynamic and steady-state behavior are described and references cited. Computer recordings are compared with results obtained from a prototype of an actual drive system. In particular, computer and test results showing the six-phase rectifier output voltage, filter inductor current, filter capacitor voltage, inverter current, as well as the stator voltage and current of the induction motor are compared. The facility of the analog computer in predicting the behavior of a large involved drive system is demonstrated.

Control circuit arrangement for controlled rectifiers

Abstract: A SYSTEM FOR REGULATING THE VOLTAGE TO A LOAD AS A LINEAR FUNCTION OF AN INPUT SIGNAL COMPRISES A CONTROLLED RECTIFIER IN SERIES WITH THE LOAD AND A SOURCE OF FULL WAVE RECTIFIED AC VOLTAGE. A CONTROL CIRCUIT IS CONNECTED TO THE RECTIFIER GATE ELECTRODE TO CONTROL THE FIRING ANGLE AS A FUNCTION OF SAID INPUT SIGNAL. THE CONTROL CIRCUIT INCLUDES A COMPARATOR TO WHICH IS APPLIED THE INPUT SIGNAL AND A CONSINUSOIDAL SAWTOOTH SIGNAL IN SYNCHRONISM WITH THE RECTIFIED AC PULSES, THE AMPLITUDE THEREOF BEING DIRECTLY PROPORTIONAL TO THE AMPLITUDE OF THE RECTIFIED AC PULSES AND STARTING FROM THE ZERO LEVEL OF THE INPUT SIGNAL. UPON EQUALITY OF THE TWO SIGNALS, THE COMPARATOR SUPPLYS A CONTROL SIGNAL TO THE RECTIFIER GATE ELECTRODE.

Semiconductor rectifier assembly having high explosion rating

Abstract: The main electrodes of a sealed semiconductor device are clamped between opposing metal members of a pressure assembly, and gaps between opposite ends of the insulating sidewall of the device and the respectively adjacent metal members are closed by resilient O-rings disposed in compression in the gaps and respectively circumscribed by rigid retaining rings.

Direct current motor control system

Abstract: A DIRECT CURRENT CHOPPER FOR CONTROLLING THE POWER SUPPLIED TO A LOAD THROUGH THE USE OF A SEMICONDUCTIVE CONTROLLED RECTIFIER AND A COMMUTATION CAPACITOR WHICH PERIODICALLY DISCHARGES INTO THE SEMICONDUCTIVE CONTROLLED RECTIFIER TO CUT IT OFF, CHARACTERIZED IN THAT IN THE EVENT THE SEMICONDUCTIVE CONTROLLED RECTIFIER FAILS TO CUT OFF OR COMMUTATE, THE CAPACITOR GOES THROUGH SUCCEEDING CHARGING AND DISCHARGING CYCLES UNTIL THE SEMICONDUCTIVE CONTROLLED RECTIFIER CUTS OFF.

Rectifier utilizing plural channels for eliminating ripple

Abstract: D R A W I N G AN OPERATIONAL RECITIFER OR CONVERTER INCLUDING A SERIES RC CIRCUIT TO CONDUCT AN AC SIGNAL TO A SUMMING JUNCTION AND A SECOND CIRCUIT PARALLEL TO THE SERIES RC CIRCUIT FOR DEVELOPING A DC COMPONENT AND AN INVERTED AC COMPONENT TO CANCEL THE AC CONDUCTED BY THE SERIES CIRCUIT. THE SECOND CIRCUIT INCLUDES AN OPERATIONAL AMPLIFIER HAVING TWO IDENTICAL DIODE-RESISTANCE FEEDBACK CIRCUITS. THE DC COMPONENT AND ONE HALF OF THE AC COMPONENT IS TAKEN FROM ONE FEEDBACK CIRCUIT THROUGH A RESISTOR, AND THE OTHER HALF OF THE AC COMPONENT IS COUPLED FROM THE OTHER FEEDBACK CIRCUIT THROUGH A CAPACITOR, TO THE OUTPUT TERMINAL. A SECOND EMBODIMENT SHOWS SUPPRESSION AND COMPENSATION CIRCUITS TO REFINE CIRCUIT OPERATION.

Rotating alternating current generator system

Abstract: A ROTATING, ALTERNATING CURRENT GENERATOR SYSTEM IS DESCRIBED IN WHICH AN EXCITER DRIVEN WITH THE GENERATOR SHAFT SUPPLIES GENERATOR FILED CURRENT AS WELL AS THE ENTIRE FIELD CURRENT REQUIRED BY THE EXCITER D-C FIELD CURRENT FOR THE EXCITER IS OBTAINED FROM THE EXCITER OUTPUT, RECTIFIED BY A CONTROLLED RECTIFIER UNIT REGULATION OF GENERATOR OUTPUT VOLTAGE (OR SOME OTHER VARIABLE MEASURABLE IN THE SYSTEM AS A VOLTAGE OR CURRENT) IS OBTAINED THROUGH CONTROL OF THE FIRING ANGLE OF THE CONTROLLED RECTIFIER UNIT, THERBY VARYING THE LEVEL OF EXCITER FIELD CURRENT TO ADJUST FOR CHANGES IN GENERATOR OUTPUT CONDITIONS TO OBTAIN REGULATION OVER A WIDE RANGE OF EXCITER OUTPUT VOLTAGES CONTAINING SUBSTANTIALLY DISTORTION, FIRING VOLTAGE FOR FIRING THE CONTROLLED RECTIFIERS IN THE CONTROLLED RECTIFIER UNIT IS OBTAINED BY AMPLITUDE-CLIPPNG THE EXCITER OUTPUT VOLTAGE AT A CONSTANT LEVEL INDEPENDENT OF EXCITER OUTPUT AMPLITUDE THE FIRING VOLTAGE WAVEFORM GENERATOR CONTAINS A CLIPPING CIRCUIT CAPABLE OF ACHIEVING SUCH CLIPPING TO THE SAME LEVEL FOR ALL RECTIFIERS THE FIRING VOLTAGE WAVEFORM GENERATOR FIRES THE RECTIFIERS THROUGH MAGNETIC CORE FIRING CIRCUITS CONTROL OF THE EXCITER FIELD CURRENT, AND THUS OF A PARTICULAR SYSTEM VARIABLE (EG, GENERATOR OUTPUT VOLTAGE) IS ACHIEVED THROUGH CONTROL OF THE RESET FLUX PRODUCED IN THE MAGNETIC CORES IN THE FIRING CIRCUITS A MANUAL REGULATOR UNIT IS PROVIDED FOR REGULATING EXCITER FIELD CURRENT TO PROVIDE CONSTANT EXCITER OUTPUT VOLTAGE AN AUTOMATIC REGULATOR UNIT IS PROVIDED FOR REGULATING EXCITER FIELD CURRENT TO PROVIDE CONSTANT GENERATOR OUTPUT VOLTAGE THE AUTOMATIC REGULATOR UNIT, WHICH INCLUDES A NON-LINEAR RATE FEEDBACK LOOP, INCLUDES SEVERAL REGULATORS, EACH RESPONSIVE TO A PARTICULAR SYSTEM VARIABLE FOR CONTROLLING EXCITER FIELD CURRENT IN ACCORDANCE WITH THAT VARIABLE WHEN ITS VALUE GOES BEYOND CERTAIN PREDETERMINED LIMITS, IN ORDER TO PREVENT SYSTEM FAILURE THE INDIVIDUAL REGULATORS ARE CONNECTED TO CONTROL THE RECTIFIER UNIT THROUGH AN ANALOG OR-GATE WHICH PASSES ONLY THAT REGULATOR OUTPUT SIGNAL HAVING THE GREATEST AMPLITUDE THE REGULATORS IN THE AUTOMATIC REGULATOR UNIT ARE: (1) THE MAIN CONTROL REGULATOR, (2) THE UNDERVOLTAGE LIMIT REGULATOR, (3) THE CURRENT LIMIT REGULATOR, (4) THE UNDEREXCITED REACTIVE CURRENT LIMIT REGULATOR, AND (5) THE PHASE-BACK LIMIT REGULATOR FOR PREVENTING COLLAPSE OF EXCITER SELF-EXCITATION, A CURRENT BOOST RECTIFIER UNIT IS PROVIDED FOR MAINTAINING MINIMUM EXCITER FIELD CURRENT UNDER PREDETERMINED CONDITIONS WHICH OTHERWISE MIGHT RESULT IN SUCH COLLAPSE PARTICULARLY HIGH RELIABILITY IS ACHIEVED BY PROVIDING TWO INDEPENDENT EXCITER FIELD CURRENT SUPPLIED AND BY PROVIDING A SELECTIVE FAILURE CIRCUIT FOR PREVENTING FAILURE IN ONE SUCH SUPPLY FROM ADVERSELY AFFECTING THE OTHER

Alternator control device having simplified charge-discharge indicator

Abstract: In an alternator driven by a prime mover of a vehicle to charge a storage battery, a gate controlled rectifier is provided to excite the field winding of the alternator and means responsive to the output voltage of the alternator is provide to effect ONOFF control of the gate controlled rectifier. To provide initial separate excitation current from the battery, a second excitation circuit including a second gate controlled rectifier is provided which is rendered inoperative as the output voltage of the alternator builds up. A lamp is directly coupled to the second excitation circuit to indicate when separate excitation current is being supplied and that the battery is not being charged.

Experience with high-speed rectifier excitation systems

Abstract: Excitation systems which utilize controlled rectifiers supplied directly from the generator terminals for the main exciter are in service at four remote generating stations. Due to the nature of the power system, these excitation systems were designed to withstand high ac overvoltages and to provide simultaneous control of a number of parallel generators. Experience in testing and operating these excitation systems is described.

Line voltage compensating pulsed power welding supply

Abstract: THE PULSED POWER WELDING PROCESS IS IMPROVED BY USING SHORTER ARC LENGTHS, WHICH BRING A NEED FOR HOLDING THE ARC VOLTAGE SUBSTANTIALLY CONSTANT. TO DO THIS, LINE VOLTAGE COMPENSATION IS REQUIRED. IT IS ACCOMPLISHED IN A PULSED POWER WELDING SUPPLY BY A FEEDBACK LOOP WHICH CONTROLS THE PORTION OF THE CYCLE DURING WHICH CURRENT IS PASSED THROUGH A TRIGGER RECTIFIER, WHICH TRIGGER RECTIFIER IS NOT COUPLED TO THE LOAD CIRCUIT. THE TRIGGER RECTIFIER CONTROLS THE PASSASGE OF POWER THROUGH A HEAVY DUTY, POWER-TYPE RECTIFIER WHICH IS ENERGIZED DURING PERIODS OF WELDING. THE FEEDBACK LOOP IS ALLOWED TO REACH A STEADY STATE BEFORE POWER IS FIRST APPLIED TO THE POWER RECTIFIER, WITH THE RESULT THAT TRANSIENTS IN THE POWER RECTIFIER LOAD ARE AVOIDED. IN THE LOOP, A COMPARISON IS MADE BETWEEN A MANUALLY CONTROLLABLE REFERENCE WAVE AND A SAMPLE WAVE DERIVED FROM THE OUTPUT OF THE TRIGGER RECTIFIER. LINE VOLTAGE VARIATIONS ARE COMPENSATED BY CHANGES IN THE LENGTH OF THE PORTION OF THE CYCLE DURING WHICH THE TRIGGER RECTIFIER IS CONDUCTING.

RECTIFYING Te–Se–Cd STRUCTURES USING A SELENIUM SINGLE‐CRYSTAL FILM

Abstract: Rectifying Te–Se–Cd structures have been prepared in the laboratory using (1010) and (0001) selenium single‐crystal films. In the forward direction the current density below 1 V follows the rectifier equation for a heterojunction and above 1 V it approaches a quadratic voltage dependence. In the latter voltage region a conventional selenium rectifier, however, shows a linear dependence.

Development of Experimental 20-kY, 36-MW Solid-State Converters for HVDC Systems

Abstract: Two 20-kV, 36-MW converters, one used as a rectifier and the other as an inverter in a pump-back configuration, have been operated successfully demonstrating the feasibility of SCRs for high-voltage high-current applications. Effects of commutation transients within the converters and on other apparatus have been thoroughly explored and analyzed.

Off delay timer and internally generated auxiliary direct current voltage source for a controlled rectifier alternating current switch for use therein

Abstract: An alternating current switch includes a full-wave rectifier with one input terminal thereof connected to an alternating current line, and the other input terminal connected by way of a load impedance to the alternating current line, with a controlled rectifier connected across the output of the full wave rectifier and while conducting providing for the flow of current through the load impedance and while nonconducting preventing the flow of current through the load impedance, with a Zener diode connecting the control element of the controlled rectifier to the anode thereof whereby a gate drive for gating the controlled rectifier on is obtained only when the voltage across the Zener diode is sufficient to cause the Zener diode to become conductive.

Automotive electric quick heat system

Abstract: 1,235,985. Supply systems for heating vehicles. FORD MOTOR CO. Ltd. 24 July, 1969 [16 Aug., 1968], No. 37235/69. Heading H2H. [Also in Divisions G2-G3] A vehicle is provided with an electrical heating system to supplement the conventional heater during the warm-up period comprising a control circuit which disables the voltage regulator during the warm-up period to allow the vehicle alternator to supply the heater elements with a large unregulated output and which effects a gradual transition between the unregulated and regulated alternator condition to prevent the production of electrical transients likely to damage certain components of the vehicle supply system, e.g. the diodes which rectify the alternator output. In Fig. 2, the alternator windings 26, 27, 28 supply a rectifier 30 and heater resistors 44, 45, 46 positioned in the conventional heater air duct to the passenger compartment, Fig. 1 (not shown). During the regulated condition the alternator field winding 43 is controlled by a substantially conventional vibratory-contact voltage regulator 73, which is disabled during the warm-up period by the opening of normally-closed contacts 66 to insert a resistor 64 in circuit and so make the voltage coil 116 of the regulator responsive to the voltage of the battery 55. Contacts 66 are controlled by a relay winding 66a in parallel with relay windings 47a, 48a controlling normallyopen contacts 47, 48 between the alternator windings and heater resistors. These relay windings are controlled by normally-open contacts 98a controlled by a relay winding 98b also having normally-closed contacts 98 in series with the field winding 43. Energization of the winding 98b is prevented by normally-open contacts 105a controlled by a relay winding 105b also having normally-open contacts 105 in parallel with the contacts 98. When the vehicle is started from cold, ignition switch 22 and electrical heating switch 23 are closed to energize the winding 105b and hence the windings 98b, 47a, 48a and 66a, a time delay being provided to open contacts 66 after closure of contacts 47, 48. During the warm-up period, contacts 105 connect the field winding 43 directly across the output of the rectifier 30 and resistor 64 absorbs the excess alternator voltage. At the end of the warm-up period, switch 23 is manually opened or thermal switches 128, 129 open automatically, the last mentioned switches being respectively responsive to the temperature of the engine coolant and to the temperature of the heat resistors 44, 45, 46. As a result winding 105b is de-energized to open contacts 105 and so open-circuit the field winding 43, since the unregulated alternator output voltage maintains the winding 98b energized and hence its contacts 98 remain open. This condition persists until the alternator voltage has fallen to about that of the battery, whereupon the winding 98b is de-energized to de-energize windings 47a, 48a, 66a and so switch out the heater resistors and commence normal regulation of the alternator. This occurs shortly after the opening of contacts 47, 48 due to the abovementioned time delay. The heating effect of the resistors 44, 45, 46 is controlled by a fan driven by a variable speed motor 140.

Delay-on-make solid-state controller

Abstract: Delay-on-make solid-state controller circuit for series connection to a load, having a bridge rectifier circuit, a silicon-controlled rectifier connected across the bridge rectifier circuit output, a current-limiting resistor, a pair of divider resistors in series connected through the resistor to the rectifier, a variable resistance and capacitance connected in series, and connected in parallel with the divider resistances, a programmable unijunction connected to the midpoint of the resistance capacitance circuit, and through a resistance to the gate of the silicon-controlled rectifier, and a connection from the midpoint of the divider resistors, to the trigger of the unijunction, a capacitance connected between the trigger of the unijunction and the cathode of the silicon-controlled rectifier, a capacitance connected between the cathode of the rectifier and its gate, and a capacitance resistance circuit connected across the bridge output.

High-current semiconductor rectifier assemblies

Abstract: The thermal cycling capability of a high-current semiconductor device is significantly increased by disposed a tungsten strain buffer in compression between a terminal of the device housing and an external pressure applying thrust member.

Electric self-cleaning oven circuit

Abstract: A control circuit for a self-cleaning oven consisting of a switching system for alternatively connecting the bake and broil elements across the 236-volt powerline to generate heat for normal cooking operations, and for connecting the elements in parallel across the 236-volt line during the self-cleaning cycle. A semiconductor rectifier in series with the parallel-connected elements is utilized to control the rate of heat rise during the cleaning cycle to a predetermined cleaning temperature level, and to further limit power application thereafter. The switching system also controls temperature-regulating components and a safety circuit responsive to abnormal operation of the semiconductor rectifier to interrupt the cleaning cycle.

Arc welding supply

Abstract: This disclosure includes a dual polarity, multiple operator direct-current welding source including a single phase or a three-phase constant potential transformer having a primary winding and a pair of secondary windings. A separate full wave diode bridge rectifier is connected to each of the secondary windings. A double pole, double throw switch unit connects the rectifiers to three weld terminals for single polarity welding or dual polarity welding. The one pole is interconnected to the positive side of the one rectifier and selectively engages a first contact connected to the positive side of the second rectifier and to the positive weld terminals or a second contact connected to the common weld terminal. The second switch pole is connected to the negative side of the second rectifier and a first contact connected to the negative side of the first rectifier and to the negative weld terminal means or a second contact connected to the common weld terminal.

Rectangular pulse modulator

Abstract: Discharge of a RLC network is controlled with a siliconcontrolled rectifier to provide a rectangular pulse for pulsing GaAs lasers.

Control circuit with controlled semiconductor and integrating switch means

Abstract: Control device for switching loads on and off, such as street lights, in response to ambient light levels comprises a photoelectric cell which has a variable resistance depending upon the intensity of incident light rays, a controlled rectifier which serves as a switch in response to the operation of the photoelectric cell, and an integrating switch such as a thermal switch operating in response to the controlled rectifier for turning the load on and off.