Abstract: A power factor controller for a switching power supply, that in one embodiment couples a power factor control circuit between an AC input and an output wherein a digital controller computes circuit currents for regulating the power supply without direct current measurements.

Abstract: A system for analyzing the operation of a switching power converter includes a digital controller for receiving an analog signal representing the output DC voltage of the power converter for comparison to a desired output voltage level and generating switching control signals to control the operation of the power supply to regulate the output DC voltage to said output voltage level. At least one portion of a control loop within the digital controller may be switched into the control loop in a first mode of operation and out of the control loop in a second mode of operation. A microcontroller emulates the operation of the at least one portion of the control loop during the second mode of operation.

Abstract: An image forming apparatus includes a main power supply section, an auxiliary power supply section, a plurality of sensors, and a power control section. The sensors are disposed at a plurality of positions. The sensors change output levels thereof upon detection of a user's operation for initiating an image forming process. The power control section switches the apparatus from a normal operation mode to the power-saving operation mode after a predetermined time period during which no image forming process is performed. The power control section detects the respective output levels of the sensors through sequential power supply from the auxiliary power supply section to the sensors. The power control section switches the apparatus to the normal operation mode upon detection of a change in output level of either one of the sensors.

Abstract: A power supply for powering an electrical load, the electrical load generating load characteristic data that determines a power supply characteristic to be provided to the electrical load from the power supply, the power supply comprising a voltage regulator for generating an output voltage to be provided as the input voltage for powering the electrical load, the voltage regulator being responsive to a reference signal for setting a characteristic of the power supply, and a control circuit for generating the reference signal for the regulator, the control circuit being responsive to the load characteristic data from the electrical load and to a selection input for selecting the type of electrical load from a plurality of electrical load types, whereby the selection input determines the type of electrical load to enable the load characteristic data to be evaluated by the control circuit to generate the reference signal for the regulator.

Abstract: Droop-control circuitry of a multiphase power converter determines when multiphase switching signals are concurrently at either a high or low state and temporarily clamps the output of the power converter to either a high or low voltage level in response thereto.

Abstract: A power supply device in a semiconductor memory includes a power control means and a power generation means. The power control means divides a self-refresh section into an active-precharge mode and an idle mode depending on an operation characteristic of the semiconductor memory, and generates a control signal for controlling power strength applied to the semiconductor memory during operation in each mode. The power generation mode generates a different power level in response to a power control signal from the power control means to provide to the semiconductor memory. Meanwhile, the power supply device according to the present invention provides relatively strong power to the semiconductor memory a predetermined time period in advance of the active-precharge mode.

Abstract: A method regulates the time constant matching of a DC/DC converter phase, further to a variation of a load applied to an output of said phase. Such phase being associated with a coil network, with a series RL circuit and a reading network 10, with a series RC circuit connected in parallel to the coil network. The method includes an acquisition step, suitable to acquire the trend of a voltage detected across the capacitance CD of the reading network 10, transforming it into a current trend, a detection step suitable to identify a variation above a certain threshold value of said current trend, an identification step, enabled by said detection step, suitable to determine a slope of said current trend and a regulation step suitable to adapt the value of said resistance RD based on said slope determined by said identification step.

Abstract: It is an object of the present invention to provide a control circuit and a control method for a current mode control type DC—DC converter capable of preventing a subharmonic oscillation even if an on-duty is not less than 50% and capable of preventing a switching frequency from fluctuating depending on an input voltage. When a high-level output signal Vo1 is inputted to a reset input terminal R of a flip-flop FF, a transistor FET1 is turned off. A phase comparator FC outputs a comparison result signal CONT in accordance with a phase difference between a delay signal FP and a reference signal FR. A delay circuit DLY outputs a high-level delay signal FP after the passage of a delay time DT adjusted in accordance with the comparison result signal CONT from the turn-off of the transistor FET1. The transistor FET1 is turned on in accordance with an input of the high-level delay signal FP.

Abstract: Digital control circuit for switching power supply with pattern generator. A method is disclosed for converting DC power from a first voltage level on an input to a different voltage level on an output for delivery to a load. Current from the input is switched to the output through an inductive element with a plurality of switches, each of the switches driven by a waveform, all of the waveforms driving the switches referenced with a predetermined relationship to a master clock and all operating on a PWM duty cycle of the master clock. The voltage/current parameters on the input and output are measured and then a control algorithm is utilized to determine a change in the PWM duty cycle necessary to make a control move, the control algorithm utilizing as inputs the measured voltage/current parameters. A pre-stored waveform pattern for each of the waveforms is then modified to reflect the change in the PWM duty cycle required for the control move.

Abstract: A multipurpose transforming device includes a power supply device that has a power import device and a power output device respectively connected with two side of the power supply device. The power import device and the power output device have connectors used for connected with different types of plugs and outlets. The power output device has at least two output lines so as to supply power to several electric device loads. The power supply device includes an AC supply unit, a voltage-regulating unit, a galvanometry unit, a memory and a microprocessor. The AC supply unit transforms alternating current into direct current. The voltage-regulating unit regulates outputting voltage from zero to rated load according to the microprocessor control. The galvanometry unit samples real-time load current and transmits the sampling value to the microprocessor. A memory stores some common rated loads so that the microprocessor compares with sampling value until two groups of value matches.

Abstract: A converter device is provided which has a power factor improving circuit that removes effects of noise superimposed on an AC power supply and reduces higher harmonics and improves the power factor. A power factor improving circuit (103) generally includes a voltage error amplifier (8), a current error amplifier (10), a comparator (11), a triangular wave oscillator (12), an output buffer (13), and a DC power supply (PS). A power factor improving unit (102) has a photocoupler (14) for detecting an output of an AC power supply (1) and a microcomputer (15), where the output (Vp) of the photocoupler (14) is given to the MCU of the microcomputer (15). A D/A converter (17) in the microcomputer (15) gives a converter output (DAO) to the power factor improving circuit (103) and the power factor improving circuit (103) gives a reference voltage (VREF) to the D/A converter (17).

Abstract: An arm-short diagnostic method for a bi-directional DC/DC converter that includes a buck switching device, a buck diode, a boost switching device, and a boost diode, is presented. The method includes detecting an output current of the bi-directional DC/DC converter, and determining whether the output current is detected in a positive direction. The method also includes maintaining supply of a turn-off gating signal to the boost switching device, and supplying a turn-on gating signal to the buck switching device, if the detected output current is in a positive direction. Finally, the method includes determining whether the output current of the bi-directional DC/DC converter increases in a positive direction, and determining that at least one of the boost switching device and the buck diode is in a short circuit state, if it is determined that the output current of the bi-directional DC/DC converter does not increase in the positive direction.

Abstract: A low noise synchronous motor including a permanent-magnet rotor and a stator with at least two pairs of stator poles and corresponding winding further includes an electronic power supply comprising a capacitor that is serially connected to one winding of only one pair of poles to act as a 90° phase shifter. A static switch that is driven by an output of the electronic power device is connected to drive another winding of said two pairs. The static switch is controlled by a sensor detecting the position at the rotor.

Abstract: A programmable controller is provided that is capable of interfacing with a remote master controller, where the programmable controller is capable of controlling an input current to at least one load that is proximate the programmable controller. The programmable controller includes at least one solid-state switch capable of controllably altering the input current to the loads. The programmable controller also includes at least one measuring element for measuring at least one parameter associated with the loads and the solid-state switches, such as the current through the solid-state switches, the current through and voltage drop across the loads and/or the temperature at or around the solid-state switches. Additionally, the programmable controller includes a processing element capable of controlling the solid-state switches, such as by controlling the current through the solid-state switches to the loads.

Abstract: An arm-short diagnostic method for a bi-directional DC/DC converter that includes a buck switching device, a buck diode, a boost switching device, and a boost diode, is presented. The method includes detecting an output current of the bi-directional DC/DC converter, and determining whether the output current is detected in a positive direction. The method also includes maintaining supply of a turn-off gating signal to the boost switching device, and supplying a turn-on gating signal to the buck switching device, if the detected output current is in a positive direction. Finally, the method includes determining whether the output current of the bi-directional DC/DC converter increases in a positive direction, and determining that at least one of the boost switching device and the buck diode is in a short circuit state, if it is determined that the output current of the bi-directional DC/DC converter does not increase in the positive direction.

Abstract: This invention includes a power supply having a plurality of cables, each corresponding to a unique electronic host device. The cable includes a memory device having predetermined power characteristics associated with an electronic host device. The cable further includes a unique mating connector for coupling to the electronic host device. The power supply includes a control circuit that reads the power characteristics and configures the power supply to charge the electronic host device. The system allows a user to carry a single power supply with multiple cables as opposed to having to transport many different power supplies.

Abstract: Apparatus for determining the frequency of an ac power signal, includes sensing circuitry to sense the ac signal. In a digital implementation of the invention, a double average of the samples is generated by a processor as the sum of the most recent sample, twice the next most recent sample plus the third most recent sample. The least mean square of a running window of the most recent double average signals is generated to avoid discontinuities at the zero crossings and to reduce the effects of noise. The frequency is determined from this least mean square value of the window of double average signals. As implemented in a protective relay, a trip signal is generated if the frequency is out of limits.

Abstract: The invention is directed to a measuring device for measuring an industrial process variable with a predetermined maximum power consumption by the measuring device. More specifically, the invention relates to a measuring device for connection to a current loop, in particular a 4-20 ma current loop, or to a digital communication, comprising devices for regulating the measuring operation of the measuring device in adaptation to the predetermined power consumption, wherein the regulating devices regulate to power consumption by the measuring operation of the measuring device in such fashion that this power consumption is approximated to the predetermined power consumption without the predetermined power consumption being exceeded.

Abstract: An apparatus and method for generating slow rise-time, high voltage electrical pulses to a load, preferably using an existing transformer/rectifier set or power supply to charge an inversion or high voltage switching circuit to produce the pulsed voltage. An energy recovery circuit (100, 102) is used to return unused energy from the load (24) back to the means for producing pulsed voltage (110, 130). A load matching circuit (120) uses a blocking diode and a capacitor for charging the load. An additional blocking diode (32) inhibits load voltage discharge back through the slow pulse generating circuit. A transformer (20) can be used to step-up voltage from the inversion circuit, or high voltage switching circuit, to the load. One or more magnetic switch stages are used to transfer energy from the inversion circuit, or high voltage switching circuit, to the load matching circuit. A fire-on voltage controller (66) triggers the inversion or high voltage switching circuit.

Abstract: A digital phase-locked loop (DPLL) (22) for use in one or more integrated circuits (20) that may be combined within an electronic system is disclosed. The DPLL (22) includes a phase detector (30) that generates a shift clock and a shift direction signal responsive to a phase difference between a system clock and a feedback clock. The shift direction signal is stored in a latch (32), applied to one input of an exclusive-NOR gate (34), and to shift direction inputs (R/{overscore (L)}) of first and second digital delay lines (38, 42). The first digital delay line (38) receives the system clock and generates a delayed clock that is distributed within the integrated circuit (20) by clock distribution circuitry, and that is applied to an input of the second digital delay line (42); the second digital delay line (42) generates the feedback clock that is received by the phase detector (30).

Abstract: Apparatus and methods for AC power regulation primarily intended for inductive loads (e.g., fluorescent lights, motors, etc.) which provide substantial reduction in power consumption while also providing a leading power factor, reduced harmonic distortion, reduced crest factor and reduced noise. The system is self-adjusting for a wide range of loads and can reduce power consumption by 25 percent in lighting loads while producing minimal reduction in light output. The system utilizes a Triac and parallel capacitor bank in series with the load. The Triac is turned on in response to a near-zero differential voltage measured across the Triac and is turned off near the peak of each AC half cycle by shunting current around the Triac. The capacitor absorbs the inductive turn-off voltage spike caused by the collapsing magnetic field in the ballast at the instant of Triac turn-off. This energy, in turn, provides longer on-period for the lamp, thereby permitting more light and increased operating efficiency.

Abstract: A communications processor is disclosed for a power generation system that permits data and control signals to be communicated to and from the power generation system and a host computer. The control signals include a power level command and power factor that are sent from a remote host to the power generation system which responds by delivering the requested power level having the desired power factor to a grid. The remote host receives performance data that permits an operator to accurately gauge the performance of the power generation system including the performance and any fault conditions of a line power unit, generator, and engine driving the generator. The communications processor unburdens the line power unit controller that is responsible for controlling power generation from the task of processing input data and driving local displays. The host may also be provided at a location remote from the power generation system.

Abstract: When the phase control is effected on a supply voltage to a load having positive resistance characteristics with respect to temperatures before a current is allowed to pass, a voltage is supplied for a current passing time T1, and the voltage is supplied for a current passing time T2 longer than the current passing time T1, and the voltage is supplied for a current passing time T3 shorter than the current passing time T2. Also, a second control pattern is effected at least once, in which the current is passed while the current passing time is kept substantially constant, then the current passing time is extended before the attenuation rate of the peak value of the resulting load current saturates, and then the current is passed while the extended current passing time is kept substantially constant. Consequently, a voltage drop can be reduced effectively without causing large distortion of the current waveform or large conduction noise by omitting an expensive noise filter or special hardware.

Abstract: A switching power supply unit controls an output voltage of a power supply without monitoring an output voltage. The switching power supply unit includes a pulse width modulator for generating a control signal to turn on and off a switching transistor. A central processing unit outputs a modulation signal to control the pulse width modulator while sensors detect an input voltage, an output current and a peripheral temperature. A table is used by the central processing unit to store information about a relation between the detected values from the sensors and an ON time of the switching transistor. The central processing unit then selects an ON time of the switching transistor from the table according to values detected by the respective sensors to thereby provide control for switching the switching transistor on and off.

Abstract: A system for controlling an Alternating Current (AC) signal to an AC powered device. The system uses a microcontroller to monitor the cycles of the AC signal supplied to the AC powered device. By utilizing cycle counting, the microcontroller can supply various numbers of waveforms to the AC powered device in order to adjust the speed and/or energy supply level to the AC powered device. At full power, all the cycles of the AC signal are provided to the AC powered device. If the speed and/or energy supply level of the AC powered device needs to be reduced by half, the microcontroller supplies every other cycle of the AC signal to the AC powered device.

Abstract: A motor starter circuit for minimizing the amount of current drawn by the motor from a power source during starting of the motor through current transformation achieved by selectively controlling actuation of a plurality of high speed switches. The circuit is for use with a alternating current power source that provides positive and negative voltage alternations, and an alternating current motor. The motor starter circuit comprises a first bidirectional switch through which line current from the power source is provided to the motor, and a pair of switch-diode combinations electrically configured to carry the current in the motor when the bidirectional switch, which is controlled to cycle between an open and a closed position, is in an open position. Actuation of the pair of switch-diode combinations is controlled based on the polarity of the motor current alternation.

Abstract: A method for controlling the power supplied to a load (1) which is powered by an AC voltage source U with a period T via a generalised phase adjustment system, includes the steps of periodically delivering a sequence of p elements to the load (1), in accordance with a predetermined set power, wherein p is an integer and each element comprises n.sub.i periods T, where n.sub.i is an integer, during which the voltage U is divided symmetrically at an angle .alpha..sub.i, the consecutive phase angles .alpha..sub.i and .alpha..sub.i+1 being different, and the combination of angles .alpha..sub.1 . . . .alpha..sub.i , . . . .alpha..sub.p being selected in such a way that they limit current harmonics, and limit a flicker effect. The method is particularly suitable for power control in electric motors.

Abstract: A new linear power control topology coupled with simple control techniques are presented which virtually eliminate the flicker problem as well as providing excellent power quality over a wide range of power levels. A modified one dimensional LMS control system similar to the standard LMS algorithm with multiple operating points and gain scheduling is also described which when combined with the new power control topology yield a dramatic reduction in flicker while yielding a universal voltage interface for world wide use.

Abstract: An electrostatic precipitator circuit has an input terminal supplied DC voltage, an output terminal connected to a precipitating capacitor, a storage capacitor connected between ground potential and the input terminal, and a recovery capacitor whose one electrode is applied with ground potential. The circuit further includes a current path switching unit having a common terminal and first and second switch terminals to be connected to the common terminal, the common terminal being connected to a non-ground electrode of the storage capacitor.

Abstract: The present invention is directed to an automatic voltage controller for an electrostatic precipitator. The invention maintains a database of operating parameters, such as the firing angle of the silicon controlled rectifiers, during previous breakdowns. The data is used for statistical analysis of the process conditions of the precipitator, enabling the invention to more accurately predict the breakdown level of the system, and providing tolerance of erratic or atypical breakdowns. The invention assembles a "rolling" data set of a predetermined number of previous breakdowns from which the invention continuously extracts a mean value and a standard deviation value, which are used to determine the setback level and the ramp level.

Abstract: Apparatus and methods for AC power regulation primarily intended for inductive loads (e.g., fluorescent lights, motors, etc.) which provide substantial reduction in power consumption while also providing a leading power factor, reduced harmonic distortion, reduced crest factor and reduced noise. The system is self-adjusting for a wide range of loads and can reduce power consumption by 25 percent in lighting loads while producing minimal reduction in light output. The system utilizes a Triac (32) and parallel capacitor bank (58) with the load (22). The Triac (32) is turned on in response to a near-zero differential voltage measured across the Triac (32) and is turned off near the peak of each AC half cycle by shunting current around the Triac (32). The capacitor (60) absorbs the inductive turn-off voltage spike caused by the collapsing magnetic field in the ballast at the instant of Triac turn-off.

Abstract: An input waveform follow-up AC power source system is shown, which can obtain a desired sinusoidal voltage or current wave continuously and with the same or a similar waveform from a constant power source, as well as being small in size and light in weight.The AC power source system, which provides a desired AC voltage or current from an AC power source, comprises a first AC switch provided between the input side and the output side and on-off operated in a predetermined cycle, and a second AC switch provided on the output side of the first AC switch and at a position to short-circuit the output side and on-off operated conversely to the first AC switch. A predetermined pause time is provided between the operations of the first and second AC switches.

Abstract: Apparatus and methods for AC power regulation primarily intended for inductive loads (e.g., fluorescent lights, motors, etc.) which provides substantial reduction in power consumption while also providing a leading power factor, reduced harmonic distortion, reduced crest factor and reduced noise. The system is self-adjusting for a wide range of loads and can reduce power consumption by 25% in lighting loads while producing minimal reduction in light output. The system utilizes a triac and parallel capacitor bank in series with the load. The triac is turned-on in response to a near-zero differential voltage measured across the Triac and is turned-off near the peak of each AC half cycle by shunting current around the Triac. The capacitor absorbs the inductive turn-off voltage spike caused by the collapsing magnetic field in the ballast at the instant of triac turn-off. This energy in turn provides longer on period for the lamp, thereby permitting more light and increased operating efficiency.

Abstract: In the open-loop control of A.C. power controllers through the phase-angle control of semiconductor valves (4), the chronological sequence of the firing signals (Z) for the semiconductor valves (4) is determined by reference signals (X). When the reference signals (X) fail for one or more periods, this chronological sequence is disturbed and damage to the load (2) to be controlled can result. Therefore, according to the invention, a method is provided whereby a safety firing signal (ZS) is always derived from the preceding firing signals (Z) when the expected reference signal (X) fails. In addition, a device for implementing the method is specified.

Abstract: A system for controlling an electrostatic precipitator adapted to be powered by an alternating power source includes a regulator for regulating at least one precipitator operating parameter in response to at least one control signal, a measurement circuit coupled to the precipitator for providing measurement signals corresponding to at least precipitator secondary voltage and precipitator secondary current. A processor coupled to the measurement circuit and to the regulator generates the control signals.

Abstract: The microcomputer reads phase difference angle data latched at the leading edge and the trailing edge of a binary logic signal composed depending on the polarity of each phase voltage of an a.c. power supply and compares the phase difference angle data with a predetermined value. Then, proportional plus integral operation is performed about the compared deviation so as to reduce the deviation to zero. The resulting value is sent to an integrating circuit in which the integrating operation is cleared and re-started each time the integrated value reaches a predetermined value. The leading inclination of the integration signal obtained by the integrating circuit changes depending on the value of the input signal. By latching the value of the integration signal at the leading edge and the trailing edge of the logic signal, the phase difference angle data can be modified. As such, if the a.c.

Abstract: A low voltage dimmer is shown with the dimming function being on a primary side of a low voltage transformer. Live voltage feeds through a triac to the primary side of the transformer with the gate for the triac being controlled by a microprocessor. To prevent burnout of the transformer if the secondary load side is open, zero crossing of the incoming signal is determined by the microprocessor. If the time constant between the zero crossing of the live voltage and the charging of a capacitor with resistance being provided by the primary side of the transformer exceeds w predetermined time period, the microprocessor will be inhibited from generating a pulse to fire the triac. When the primary side of the transformer has been opened, the load on the secondary side can be re-established, i.e. light bulb replaced. Power for the microprocessor is from the charging of a capacitor used to provide the triggering signal to the microprocessor. Also the microprocessor may be triggered from remote locations.

Abstract: An apparatus for triggering a plurality of thyristor devices has a clock generator for producing a pulse train output and a digital counter for counting the number of pulses generated by the clock generator. The digital counter has a digital output which is received by a decoder. The decoder has a plurality of output lines, only one of which is in a high logic state at any time depending upon the digital output from the digital counter. A memory unit contains a plurality of digital control data, only one of which is accessed during the duration of the pulse train output. The memory unit has a plurality of memory data lines which are divided into several groups and which are used for reflecting the accessed one of the control data thereon.

Abstract: A solid state circuit interruption arrangement monitors a current path to provide protection to both a load and a solid state switch. The arrangement includes an energy absorber for absorbing energy from the current path in response to the solid state switch interrupting the current path, and a control circuit for periodically generating the interrupt signal to interrupt the current path for prescribed intervals and to control the current supplied to the load between a maximum current level and a minimum current level.

Abstract: A method and apparatus for controlling single or polyphase a.c. power controllers when controlling a.c. power controllers by means of phase angle control of semiconductor switches, the firing signals on the one hand must be long enough to guarantee a reliable firing and, on the other hand, be short enough to prevent an overloading of ignition amplifiers. According to the invention, therefore the use of firing signals with variable temporal lengths is provided, which end at least approximately at the reestablishment of the current flowing in the phase that has been fired. Moreover, devices for implementing the method are specified.

Abstract: A controller associated with a dissipative electric load controls the level of average power applied to the load by an electric energy distribution network that supplies the dissipative load with a supply voltage. The controller comprises a detector for detecting a predetermined pulse duration modulation signal embedded in the level of the supply voltage provided by the distribution network, and a device for transmitting electric power originating from the distribution network to the load. The device for transmitting comprises a device for reducing the level of average power transmitted to the load, in response to a detection of said pulse duration modulation signal in the level of supply voltage. A decrease of the line voltage level for a given duration of power distribution voltage is initiated in order to control the average power consumption of the loads.

Abstract: An apparatus for triggering a plurality of thyristor devices includes a full-wave rectifier circuit having a sinusoidal pulse output, a Schmitt trigger circuit to generate a constant amplitude pulse signal when the sinusoidal pulse output exceeds a certain triggering level, a clock pulse generator to generate a predetermined number of clock pulses within the duration of the constant amplitude pulse signal, and an address counter to receive the generated clock pulses. The address counter has a digital output corresponding to the number of clock pulses received. A read-only memory unit has digital data stored therein. The memory unit has a plurality of address lines to receive the digital output of the address counter and a set of output data bits corresponding to the stored digital data which is accessed according to the digital output of the address counter. Each thyristor device is triggered into the conducting state by one of the output data bits of the memory unit.

Abstract: Form factor measurement and fault detection equipment to determine proper sizing of electrical components and efficiency of an electrostatic precipitator (22) by calculating a system form factor from either primary voltage or current. A power source (10) connects serially to an inverse parallel SCR1 and SCR2, to a current limiting reactor (16), and to a T/R set comprising a transformer (18) and rectifier (20) which supply power to precipitator (22). A current transformer (26) senses input current between the reactor (16) and T/R set (18,20) to signal an input scaling and signal conditioner (28) connected to a current meter (34), a voltage meter (39) and a computer (40) having a display monitor (42). The computer (40) is also connected to an SCR control circuit (24) of SCR1 and SCR2. The appropriate electrical characteristic is converted to both its RMS value and average value and then sent to the computer (40).

Abstract: A remotely controllable, full scale, AC or DC power attenuator, for attenuating power to a load as a function of an input control signal which represents a selected percentage of power to be applied to the load. Bidirectional series switch means are responsive to the input control signal for connecting and disconnecting power to the load.

Abstract: A compact, liquid cooled, ferrite phase shifter is capable of handling high power microwave signals without thermally stressing the ferrite core. The ferrite core is mounted on spacers inside of a hermetically sealed wave guide filled with a thermally conducting fluid. Heat transfer from the core to the housing is symmetrical thereby eliminating or minimizing thermal bending stresses on the phase shifter. Heat from the core is also coupled through the fluid to the phase shifter window for deicing the window.

Abstract: A controller can control controlling a precipitator. The controller has a power modulator. The modulator has a control terminal and is coupled to the precipitator. The power modulator is adapted to be powered by an alternating current. The modulator can operate to regulate the drive to the precipitator in response to a control signal on the control terminal. The controller also has a measurement means coupled to the precipitator for providing a plurality of measurement signals corresponding to a plurality of operating parameters of the precipitator. Also included is a processing means having a program. The processing means is coupled to the measurement means and the power modulator for producing the control signal and for regulating the power modulator in response to the measurement signals.

Abstract: A control device for switching a thyristor in a circuit including an a.c. voltage source, which comprises firing signal circuit having an input for receiving control signals, an output for providing firing signals for a thyristor and a detector for detecting zero-crossings of an a.c. voltage provided by the a.c. voltage source. The firing signal circuit further comprises an accumulating circuit for accumulating the control signals and for providing a firing signal when both the detector detects a zero-crossing of the a.c. voltage and the value of the accumulated signals is equal to or exceeds a first predetermined value, and subtracting circuit for subtracting a second predetermined value from the value of the accumulated signals when the firing signal is provided.

Abstract: A controller for a load such as the heater elements of an actuator for drying the various zones or slices of a moving sheet of a papermaking machine includes silicon controlled rectifiers for each zone or slice of the moving sheet whose firing angle is controlled by an external power command signal. This power command signal is processed by a digital signal processor which strobes at a high rate the line voltage and load current to provide a closed loop feedback control technique for power being applied to the load and in addition, the processor, at the same time, has an open loop firing angle control routine which has a fast response time to protect against abnormal conditions within one-half cycle of load voltage.

Abstract: A power controller for supplying separately a regulated power source to a plurality of "S" lines and for monitoring line-status conditions on the "S" lines so that each "S" line is controlled independently includes an analog section for delivering power independently to each of the "S" lines and for detecting line-status conditions on the "S" lines. The power controller also includes a microprocessor interface section for communicating with the microprocessor and for controlling the analog section. The analog section is formed of a plurality of output drivers for supplying individually the power to the plurality of "S" lines and line-status detector circuits for sensing line-status conditions on the "S" lines to provide a set of status logic signals for each "S" line. The microprocessor interface section includes an address register for storing a plurality of addresses corresponding to the line-status conditions to be monitored on the "S" lines.

Abstract: An electric continuous-flow water heater generates a basic power with heating resistors in heating passages and a controllable power with three heating resistors in heating passages. The controllable power is controlled by a control system through a triac. At low flow rates two phases and a low controllable basic power is connected to the heating resistors. At high flow rates the heating resistors are star-connected and the controllable heating-resistors are delta-connected. An electric power output stage comprises a mains rectifier bridge, a Schmitt-trigger connected to the output thereof and a frequency divider with two outputs.The signals at the outputs are set by an edge of each third pulse and are reset by the corresponding edge of the following or next but one pulse. A semiconductor relay is optionally by the signals at the outputs through a selector switch or a logic circuit and is rendered conductive for one, two or three half waves.