Abstract: Minimum input power and maximum efficiency occur at a characteristic optimum slip value which can be calculated for any induction motor using methods described. Efficiency is shown to be independent of output power when a variable voltage controller reduces the voltage approximately as the square root of the load torque to maintain the required slip during part load operation. Saturation effects do not significantly change these results.

Abstract: PURPOSE: To prevent an output voltage from quickly dropping when a vehicle speed is reduced and the revolution of a generator is reduced. CONSTITUTION: If a transistor 52 is turned on and off in a voltage regulator switching circuit 50 in accordance with the running state of a vehicle to switch a regulating voltage, the regulating voltage is gradually switched between a low voltage and a high voltage by a voltage regulator control circuit 100. When a vehicle speed is reduced and the transistor 52 is turned off, if it is decided by a revolution deciding circuit 40 that the revolution of an alternator 10 is reduced to the revolution not higher than a predetermined revolution, a transistor 53 is turned on and the regulating voltage is switched to a low voltage before the vehicle stops. Therefore, an output voltage can be gradually reduced in accordance with the regulating voltage before the revolution of the alternator 10 drops and the generation capability becomes insufficient, so that the quick drop of the output voltage can be avoided. COPYRIGHT: (C)1995,JPO

Abstract: A power controller determines which of a plurality of possible input voltages is present and configures a load to operate at that present input voltage.

Abstract: A solid state power supply and light emission controller for a cold cathode luminous tube which converts standard alternating current line voltage, or direct current voltage, into a variable repetition rate pulse alternating current voltage for energizing the tube and for controlling the light emission thereof. The power supply and controller provides for essentially constant light emission from the tube in the presence of variations in the load presented by the tube, ambient temperature and line voltage. The power supply and controller includes a flyback transformer circuit which, in turn, includes circuitry for monitoring the line voltage and the load presented by the tube, and for providing an automatic cut-off when the line voltage decreases below a predetermined level. The power supply and controller finds use, for example, with cold cathode luminescent tubes such as fluorescent-mercury-argon-neon, fluorescent neon, clear mercury-argon-neon, and clear neon.

Abstract: A system for automatically controlling output voltage to correct for varying input voltage utilizes a transformer having a movable core structure. The output voltage from the transformer is sensed and made to conform to a predetermined standard by moving the movable core structure, which is then locked in position after its adjustment. Voltage changes are step-free, and linear voltage control with respect to time is achieved through non-linear movement of the core structure over a range of variation of the output voltage.

Abstract: PURPOSE:To enable to continue the operation stably even when a power source voltage drops due to instantaneous power interruption by controlling so that the DC voltage inputted to an inverter becomes substantially constant when the power source voltage drops due to the instantaneous power interruption. CONSTITUTION:A speed controller 12 outputs a torque current command in response to a deviation between a speed command N* and a speed detection signal N. A slip frequency detector 14 calculates a slip frequency command by a torque current command, the slip frequency command is added to a speed detection signal N, and applied to an oscillator 16. The detector 14 outputs the primary current command by the output of the oscillator 16, the torque current command and the exciting current command. When an instantaneous power interruption occurs, an instantaneous detector 27 is operated to switch a switching circuit 13. Thus, a voltage controller 25 outputs a torque current command in response to a deviation between the DC input voltage of the inverter 4 and the set value.

Abstract: The present invention relates to a medical X-ray radiation power supply apparatus wherein a DC-operated switching circuit is connected at the primary side of a high voltage transformer, and a comparator circuit compares the voltage predetermined by a tube voltage setting circuit with an actual tube voltage detected by a tube voltage detector circuit, then the gain of a comparison voltage is raised so that the actual tube voltage can quickly reach the predetermined tube voltage value, thereby tube voltage errors, which are caused by short photographing time in a medical or breast X-ray photographing apparatus, are eliminated

Abstract: PURPOSE:To provide a controller for a vehicle charging generator which can smoothly increase a speed of an engine corresponding to an increase in an electric load. CONSTITUTION:The controller for a vehicle charging generator comprises a detector 221 for detecting use of a load having a large capacity, a timer circuit 222 for starting counting when use of the large capacity load is detected by the detector 221 and counting a predetermined time after the start of rise of the engine speed corresponding to the detection of the use of the load, and exciting current limiting means 212, 223 for limiting exciting currents to be controlled by a generating voltage controller 221 to a predetermined value or less until the timer circuit 222 is time-up from the time of detection of a load increase, thereby reducing a load to be applied to the engine by the generator when the engine speed is raised.

Abstract: In an inverter for converting a direct voltage into an alternating voltage, having a number of n circuit units connected in series between two outputs, each circuit unit comprising a series connection, having a direct voltage source and a switch with a switching connection, and a unidirectionally conducting circuit element disposed in parallel with the series connection, the inverter having a control unit which operates the switching connections of the switches to render the switches conductive or non-conductive, in order to minimize the circuitry the voltage values of the direct voltage sources have the values U=UO.2.sup.ν (ν=0, . . . n-1, O having any desired value), and the control unit is an analog-digital converter (1) having an analog input and digital outputs (Aν), whose analog input receives a reference alternating voltage and from whose digital outputs the 2.sup.ν output is connected to the switch connection (Sν) of the switch of the circuit unit containing the voltage source with the voltage value Uν. Application to mains-connected photovoltaic solar energy installations.

Abstract: A sweep voltage from a sweep voltage generator is provided to sweep start and stop adjusting means, the outputs of which are summed by a summing circuit and, by the summed output, the oscillation frequency of a voltage controller oscillator is controlled. The oscillation frequency of the voltage controlled oscillator and the output frequency of a reference signal generator set to a sweep start frequency are compared by comparing means. The output of the sweep voltage generator is put in a sweep start state and sweep start adjusting means is adjusted in accordance with the output of the comparing means, thereby to cause the oscillation frequency of the voltage controlled oscillator to agree with a set sweep start frequency. The output of the sweep voltage generator is put in a sweep stop state and sweep stop adjusting means is adjusted in accordance with the output of the comparing means, thereby to cause the oscillation frequency of the voltage controlled oscillator to agree with a set sweep stop frequency.

Abstract: PURPOSE:To put a generator in operation continuously under manual control by locking an automatic voltage controller when an abnormal reference voltage is detected during automatic voltage regulating operation by a meter relay, etc., connected to a reference voltage circuit. CONSTITUTION:If an output voltage drops owing to troubles of a Zener diode used for an automatic voltage regulator AVR for a generator, a meter relay 9 and an auxiliary breaker 10 operate. While the device AVR is locked momentarily through a contact 11, a warning or trouble display is performed through a contact 12 to inform an operator of the trouble. Consequently, even if a fault occurs in the reference voltage circuit of the device AVR during the operation of the generator by the device AVR, the device AVR is locked momentarily and the generator is controlled manually to operate continuously.

Abstract: A temperature tracking D.C. motor speed controlled fan (15) employs a temperature sensitive circuit element (35) to control the output voltage of a voltage regulator (24) which is applied as the D.C. input to the fan motor circuit (18). Typically, the voltage regulator (24) is an integrated circuit voltage regulator having an adjustable output voltage, variable as a function of circuit elements connected thereto. In each of several circuit arrangements, a thermistor (35) senses temperature to increase voltage and consequently fan speed with rising temperatures. In a preferred embodiment the thermistor is used to control the base drive of a transistor (Q1) connected to the regulator. A Zener diode (02) connected in series with the transistor (Q1) can provide a minimum output voltage from the voltage regulator, keeping the D.C. motor (10) of the fan turning at a low, quiet speed. The voltage applied to the thermistor (35) can be derived partly or wholly from the input to the regulator, reducing or eliminating the negative feedback effect that comes from deriving the thermistor voltage from the controlled output. A voltage stabilization circuit including a Zener diode (D3) at the input to the voltage regulator can provide a stabilized voltage to the thermistor.

Abstract: This device provides a non-stabilised load voltage and additionally a stabilised load voltage. The voltage supply device can correct fluctuations in the supply voltage rapidly and well, filter out voltage peaks on the supply voltage and, when the supply voltage drops below a permissible minimum value, disconnect loads. The voltage supply device is particularly suitable for sensitive electronic loads such as microcomputers and microprocessors in motor vehicles.

Abstract: PURPOSE:To enable to reduce the size of a smoothing choke coil by connecting a switching element which is controlled ON or OFF with a signal of a voltage controller between a rectifier and an inverter and controlling the DC input of the inverter. CONSTITUTION:A switching element 17 is inserted between a rectifier 1 which employs diodes 8 and an inverter 2 which is controlled by a frequency controller 3, and turned ON or OFF by a voltage controller 4 which has sawtooth wave oscillating means 19 and control means 20 for varying the duty cycle by converting the sawtooth wave of the means 19 to a rectangular wave, thereby driving an induction motor M. Accordingly, the DC voltage from the rectifier 1 can be regulated by the ON or OFF of the element 17, the smoothing choke coil 7 can be reduced in size by selecting the frequency to a higher value, and the reduction in the cost of the rectifier 1 and the improvement of the entire efficiency can be performed.

Abstract: PURPOSE:To protect the load and to prevent the burning of an adjusting transformer, by providing a control circuit to control a breaker and an automatic switch which are set to a static automatic voltage controller of direct switching system. CONSTITUTION:A line led from a substation is connected to a load 2 via a breaker 5, a voltage controller 3 having an adjusting transformer with multistage tap and an automatic switch 6 which form a static automatic voltage controller. A control circuit 8 controls the breaker 5 and the switch 6 and then opens the breaker 5 and then the switch 6 when an overcurrent is detected and when a short circuit is detected between the adjusting transformer and the tap. Then the controller 3 is separated from the line to protect the load and to prevent the burning of the adjusting transformer.

Abstract: PURPOSE:To enable to start smoothly an induction motor by an inverter by a method wherein an output voltage of the inverter is made high for the prescribed time at the first stage of starting, and after then the voltage is restored to a steady V/F pattern CONSTITUTION:An acceleration and deceleration limiting circuit 7 inputs an output signal of a frequency setter 6, and applies a command signal to a V/F converter 11, a voltage controller 8, and a starting torque compensating circuit 16 The starting torque compensating circuit 16 applies a differential signal differentiated the command signal to the voltage controller 8 to output a high output voltage command only at the first stage of starting, and makes the output voltage of the inverter 3 high through a comparator 9, a modulator 14, a distributor and a base driving circuit 15 Accordingly starting can be performed smoothly

Abstract: PURPOSE:To suppress the abnormal rise of the output voltage of a generator with a capacitive load by connecting an auxiliary transistor which is conducted when a field current is flowed reversely in parallel with a field coil. CONSTITUTION:A voltage regulator 6 compares the output voltage of an output coil 2 with the reference voltage of a Zener diode 14 to control a field current if supplied from an auxiliary coil 3 to a field coil 5. When a load is capacitive, an alternating voltage is induced in the coil 5. When the voltage Vf is reverse to an arrow, the field current is flowed through diodes 26, 32. When the voltage induced in the field coil is inverted in Vf direction, the field current is flowed through the transistor 31 and diodes 38, 39. Thus, the abnormal rise of the output voltage of the generator can be suppressed.

Abstract: PURPOSE:To effectively protect an inverter by stopping the inverter when the load current of the inverter exceeds the prescribed value and restricting the outputs of a voltage controller and a current limit controller to minimum values. CONSTITUTION:The output frequencies of inverters 2a, 2b are determined by a common reference oscillator 21. The deviations of the output voltages of the inverters 2a, 2b are respectively detected by voltage deviation detectors 18a, 18b, and applied to voltage controllers 11a, 11b and current limit controllers 12a, 12b in the direction to reduce the deviation of the voltage. When the load currents of the inverters 2a, 2b exceed the prescribed value, the inverters 2a, 2b are stopped, and the outputs of the controllers 12a, 12b and 12a, 12b are restricted to the minimum values. Thereafter, the operations of the inverters 2a, 2b are restarted after the prescribed time, and the output voltages and currents are gradually raised.

Abstract: PURPOSE:To obtain a voltage controller having good heat sink with small outer profile size by containing a hybrid integrated circuit device mounted on the surface of a ceramic circuit substrate with a power control element chip and a chip-shaped circuit constituent of a control circuit in a sheathed metallic case. CONSTITUTION:A power control element chip 21 coated and dried with protecting resin 21b through a copper plate 21a is mounted on the surface of a ceramic circuit substrate 20 formed with a thick film wire conductor, and a control circuit 22 which is composed of a switching element chip or diode element chip 22a coated and dried with protecting resin 22a1 and a laminated chip condenser 22b for controlling the operation of the power chip 21 is mounted on the surface of a substrate 20 surrounded as designated by one-dotted chain line. Further, an external lead wire 23 is formed at the edge of the side of the chip 21. In this manner, a voltage controller which has small outer profile size and good heat sink can be inexpensively obtained.

Abstract: PURPOSE:To enable the precise control of an induction motor by employing as a feedback amount the fundamental wave components of an output voltage. CONSTITUTION:The fundamental wave component E1 of an output of a pulse width modulation PWM inverter is given by E1=g(KH).ED, where KH (amplitude ratio) represents the ratio of the peak value of a modulated wave with that of a carrier, g(KH) represents the function of the KH, and ED represents the input DC voltage of the inverter. The output voltage of the inverter is controlled by the component E1 which is obtained by the above equation as a feedback amount. In this case, when the prescribed PWN signal of a switching element forming the PWM inverter 9 is, for example, applied to the element of positive side of U phase, its phase voltage EU becomes the waveform having the same peak value as the input voltage ED of the inverter and the same pulse train as the PWM signal. This phase voltage EU can be expressed by the equation as shown. In the equation, the harmonic component E2n-1 of (2n-1) place can be obtained by developing the phase voltage EU in Fourier series. The control system can be divided into a speed controller 20 and a voltage controller 30.

Abstract: PURPOSE:To obtain a stable regenerating brake to a low speed of an AC electric motor vehicle by supplementing an armature current with power from a trolley wire through a main rectifier at a separately-excited generating braking time. CONSTITUTION:A brake current flows in a circuit which has an armature 3a, a brake resistor 4, a P/B converter 51(B side), a diode 11 at the regenerating braking time. On the other hand, an armature voltage controller 2 supplies electric power to the armature 3a and the resistor 4 through the converter 52 (B side) and a resistor 12 when the current of the armature 3a decreases lower than the specified value. In this manner, since the brake current can be maintained constantly irrespective of the speed, stable regenerating brake characteristic to the low speed can be obtained.

Abstract: The invention relates to a circuit arrangement for producing an AC voltage from a DC voltage. The form, amplitude and frequency of the AC voltage can in this case be predetermined in a required-value stage, a magnitude signal and a polarity signal being obtained from the control deviation by means of a required value/actual value comparison. The magnitude signal controls a variable pulse width switching regulator (on-off controller, chopper-type regulator, chopper regulator, switched-mode regulator) of a voltage converter, while the polarity signal alternately switches on (via a comparator) two switching stages which are allocated to the polarities of the output voltage.

Abstract: PURPOSE:To prevent the overheating by providing a comparator which produces the output when the temperature of the glow plug has exceeded over the predetermined level and a comparator which produces the output when the source voltage has exceeded over the steady voltage and stopping the super-quick heating by means of the signal from said comparators. CONSTITUTION:Upon closing of a key switch 2, the super-quick heating of the glow plug 1 is started through a relay contact rl1 while upon reaching to the predetermined temperature TM prior to the preheat setting Ts, the differential potential between the points (a) and (b) will exceed over the setting of a comparator C1 to open the relay contact rl1 through OR gate 3 and an amplifier 4 thus to stop the super-quick heating. After elapsing the setting time of a timer 5 which functions after closing of the switch 2, the relay contact rl2 will close and a voltage drop resistor Rd is inserted to lower the heating speed. While when the voltage higher than the steady voltage has occurred through the short time starting of the engine, the comparator C2 will produce the high voltage continuing signal thus to open the relay contact rl1 through OR gate 3 and to prevent the breaking of wire due to the overheating of the heating coil.

Abstract: The regulator according to the invention is constructed such that it can be coupled to various power circuits and such that the e.m.f. of the motor or the output voltage of a tachogenerator can be used as the control variable, it being possible to integrate the most important components in one circuit. The function of the regulator is essentially characterised by a square-wave voltage which is synchronous to the network AC voltage and, as a result of a special type of generation has a high-low transition at the zero cross over and a low-high transition after approximately 2 ms and, as a result of superimposition of a second voltage, produced by an RC element in conjunction with a voltage divider which is variable via a foot controller, results in a voltage which, in comparison with a measurement voltage which is stored on an RC element via a differential amplifier, generates a further square-wave voltage whose high-low edge is used via a pulse amplifier to trigger a power semiconductor, and whose low potential disconnects the acceptance of measured values.

Abstract: PURPOSE:To prevent an erroneous compensating operation, by adding a means for giving a single polarity transfer characteristic, such as a diode, etc., to a voltage controller of an electric power supply unit provided with an automatic voltage controller and a line drop compensating circuit. CONSTITUTION:In an input part of an automatic voltage controller 3 attached to an electric power supply unit 2, output voltage detected by a voltage detector 11 connected to an output terminal A is compared with a set value of a setting device 5. Also, as a line drop compensating circuit, a comparing means 14 for deriving a difference between an output of a voltage detecting circuit 12 provided on the output terminal A, and an output of a voltage detecting circuit 13 provided on a load terminal B is provided. Also, a diode 15 for setting an output of the comparing means 14 to an auxiliary set value as to only its single polarity, and leading it to a comparing point of the input part of the automatic voltage controller 3 is provided. In this way, a negative output generated by the comparing means 14 is cut by the diode 15, therefore, an erroneous compensating operation can be prevented.

Abstract: PURPOSE:To improve an initial winding property of a steel plate, and to prevent generation of an initial winding loose coil, etc., by controlling a load in case when a steel plate is initially wound to a winding machine, so as to make it approach a load in case when the initial winding is satisfactory. CONSTITUTION:A load current of a winding machine driving DC motor in case when a steel plate is initially wound to a winding machine is compared and operated with a set value corresponding to a load current of said motor in case when initial winding of the steel plate is satisfactory. Subsequently, this compared and operated output is inputted as a correcting signal to a voltage controller of the prestage of a controlling circuit which switches the winding machine to tension control from speed control after the steel plate has been wound to the winding machine. Subsequently, the number of revolutions of the motor is controlled so that said compared and operated output becomes small. Thereafter, the speed control is switched to the tension control.

Abstract: PURPOSE:To suppress a rotor vibration with a simple structure by altering at least one of the output voltage and frequency of a power converter in a stepwise manner in a specific range of a motor speed. CONSTITUTION:An AC motor 12 is driven by the output of a power converter 11. The output voltage of the converter 11 is controlled by the output of a voltage controller 13, and is controlled by the butting of the outputs of a voltage reference circuit 14 and a voltage feedback circuit 15. The rotating frequency of the motor 12 is detected by a speed detector 16, and the output of the detector is inputted to a frequency discriminator 17. The discriminator 17 generates a signal when the rotating frequency of the motor 12 is in the specific frequency range, a voltage throttling circuit 18 is operated by the signal, thereby decreasing the voltage reference of the circuit 14.