Abstract: An electrostatic precipitator is fed high voltage pulses by a pulse generating circuit including a high voltage transformer and a first thyristor switch connected in series with a primary winding of the transformer. Magnetic saturation of the core of the high voltage transformer is prevented by recurrently short circuiting the primary winding of the transformer by means of a second thyristor switch connected in parallel to the primary winding. The second thyristor switch is closed for a period of time extending from a first instant following a high voltage pulse crest to a second instant at or before the start of a pulse generating cycle subsequent to the pulse crest.

Abstract: A multimode electronic circuit for driving bells or other electromagnetic devices. An important feature of this design is that it allows one circuit to function in a variety of modes: either in the vibrating mode or single stroke mode, both being operative with either an AC or DC source.

Abstract: A circuit for combining independently controlled AC and DC voltages in which AC and DC voltages are respectively applied to different inputs of a first amplifier, its output is connected to a first output terminal, the DC voltage is applied to the input of a second amplifier, its output is connected to a second output terminal that is grounded for AC, a voltage divider is connected between said output terminals and the gains of the amplifiers for DC are the same.

Abstract: This power supply device comprises a voltage regulating element, a constant-current source, first and second constant-current circuits, and a current switching circuit interposed between the first and second constant-current circuits and the constant-current source, and by comparing an input voltage with an output voltage to introduce constant current from the first constant-current circuit to the voltage regulating element when the input voltage is higher than the output voltage, while introducing the constant current from the second constant-current circuit to ground terminal when the input voltage is lower than the output voltage. Thus, a stabilized DC voltage may be produced from a DC voltage including a superposed AC signal without interfering with the AC communications signal.

Abstract: Temperature detectors are disclosed which employ, as their active elements, pieces of partially pyrolyzed polymer material which switch to a more highly conductive state under appropriate imposed electrical bias conditions when the ambient temperature increases above the switching temperature of the detector.

Abstract: An electric power source for use in an electrostatic precipitator includes a first high voltage DC source having an output terminal adapted to be connected to discharge electrodes of the electrostatic precipitator. An inductor is connected at its one end through a coupling capacitor to the output terminal. A controlled rectifier is connected at its an anode to the other end of the inductor and has a grounded cathode. A diode is connected in a reversed parallel to the controlled rectifier. There is also provided a second high voltage DC source having a high output impedance and connected to the inductor, and the controlled rectifier is turned on and off by a controller.

Abstract: Method for improving the dielectric strength of insulation not subject to fluid pressure and used to insulate a conductor element, such as the conductor of a cable, an insulator, etc., subjected to direct current high voltage in which, during or prior to service use thereof, the insulation is subjected continuously or intermittently to a varying amplitude, direct current voltage. The amplitude of the variation is small relative to the average value of the direct current voltage and the frequency of the variation, preferably, is less than 60 Hz. Also, apparatus for providing the voltage of varying amplitude including an alternating current generator in series between the direct current source and the conductor element and inductor in parallel with the generator, the inductor having a low ohmic resistance and a high reactance relating, respectively, to the ohmic resistance and reactance of the generator.

Abstract: A communication system for communicating analog and digital data with a process variable, e.g., pressure, transmitter over the two wires which supply power to the transmitter apparatus. The digital communication operation is half-duplex, bit serial transmission and is represented by the currents and voltages in the transmitter communication loop which are selectively introduced between process variable analog data transmissions of 4-20 ma. A plurality of bit cells are provided for each data word or byte between a start bit and a parity bit cell. Following the completion of transmission of the digital data, a predetermined time period is introduced to enable the resumption of transmission of process variable data. Multiple byte digital data transmission can also be effected between process variable analog transmissions by having a byte spacing less than the predetermined time period preceeding the 4-20 ma process variable transmissions.

Abstract: A current regulator for supplying dc power to a telephone line employs a resistor feed circuit in conjunction with a solid state feed circuit. The dc line current flowing through both such elements is monitored by a sensing circuit which drives the solid state element in a manner to maintain a desired magnitude of dc line current. The resistor value may be arbitrarily chosen so that the circuit power is shared in a desired proportion between the resistor and solid state element. When used in a telephone line in series with ac voice signals the regulator employs a capacitator and diode bridge arrangement to reduce the ac impedance thereof, improve longitudinal balance and allow bi-directional current.

Abstract: A method for operating an electrostatic precipitator with a DC voltage and superimposed pulses or superimposed AC voltage in which individual parameters such as amplitudes, pulse repetition frequency, pulse width, etc. are iteratively and continuously varied in such a manner that the sum of the pulse and the DC voltage power approaches a minimum. A computer which calculates, from the dust load and the absorbed electric energies of the filter, control commands for the DC and pulse voltage source is used for this purpose.

Abstract: This application discloses circuits for use with arc discharge devices wherein a D.C. or A.C. high frequency, high voltage source is provided in conjunction with either a low frequency or D.C. voltage source. The high frequency, high voltage circuit is a low power circuit providing sufficient voltage to ionize the arc. If desired the low power circuit may also control the major arc power obtained from the low frequency or D.C. source which does not require a ballast. By virtue of this arrangement much smaller, lighter and lower cost circuits than conventional ballast circuits can be used.

Abstract: A device for the remote control of the angular position of an aerial rotor comprising a d.c. motor for the rotation of the rotor and a drive circuit adapted to cause the rotation of the motor in one direction when it receives as input a d.c. voltage higher than a reference value and in the opposite direction when it receives as input a d.c. voltage lower than the reference value. The device provides for a feeder, in proximity of the receiver, for generating at least one d.c. control voltage and comprising a regulator of the value of the voltage as a function of the desired angular position of the rotor of the aerial, and a regulator and stabilizor of the d.c. control voltage, located in proximity of the drive circuit of the motor, to obtain from the d.c. control voltage a stabilized constant voltage of a value lower than the minimum value of the d.c. control voltage, for the feeding of the drive circuit and the motor.

Abstract: An improved power supply for an electric precipitator which includes a d-c voltage source and a pulsed a-c voltage source coupled to the high-voltage electrodes of the precipitator. The improvement of the invention comprises the pulsed a-c voltage source comprising a high-voltage transformer including a primary winding and a secondary winding, the latter of which is coupled to the high-voltage electrodes of the precipitator. A d-c voltage source has one of the voltage terminals thereof coupled by means of a center tap to the primary winding of the transformer and the other of its voltage terminals coupled to a pair of thyristors and a pair of diodes connected to the ends of the primary winding of the transformer. The thyristors are coupled in anti-parallel relationship with the diodes and are adapted to be triggered in alternating fashion at the frequency of the voltage pulses desired to be generated.

Abstract: The current from an external AC power source is rectified to charge a DC battery and conduct current therethrough in series with a load during one-half of each power cycle of the external source. During the other half of each cycle, current is conducted through the load by discharge of the battery through a transistor that is switched to its conductive state by a phase control transformer connected to the power source.

Abstract: A power supply and a method for providing in a convenient and inexpensive way an unlimited range of direct currents with superimposed alternating sinusoidal or non-sinusoidal currents to a single load or to a number of loads in parallel. A novel power supply derived from a conventional one by purposely unbalancing AC potentials of load terminals so that an additional AC voltage drop appears across the load. This unbalancing is accomplished through changing AC potentials of one or both lead terminals by connecting one of the terminals to different points along a special unbalancing transformer winding and/or by connecting capacitors between a load terminal and different points of this unbalancing winding.

Abstract: Disclosed is a ringing power supply for developing a ringing signal having an AC voltage combined with a regulated DC voltage, of magnitude smaller than the magnitude of the AC voltage, from a source having the AC signal combined with an unregulated DC voltage. The ringing power supply comprises a control circuit responsive to the AC and DC voltages of the source for developing a replica signal of the regulated DC voltage with its superimposed AC voltage, and a regulator responsive to the developed replica signal and to the source for providing the desired ringing signal.

Abstract: A model railway or road vehicle installation in which vehicle-mounted electric drive motors are supplied through contact with track conductors, including a power supply providing an intrinsically safe a.c. component of such frequency and amplitude as to be capable of breaking down any contact inhibiting dielectric layer of dust, grease, metal oxide etc. on the track conductors, in addition to the normal d.c. component powering the vehicle. An automatic arrangement suppresses the a.c. component so long as good electrical contact is maintained so that the a.c. component is provided only when necessary. For facilitating slow speed operation, the d.c. supply is pulsed with a variable mark to space ratio dependent upon the desired vehicle speed thereby to maintain the torque output of the vehicle motor.

Abstract: An alternating current energy converter comprising a direct energy converter, the internal resistance of which is so connected into an alternating current circuit that current flows as rectified current therethrough and the reactance of the alternating current circuit is greater than the resistance of the direct energy converter.

Abstract: A transmission line having a pair of wires enclosed in a shield is used to simultaneously transmit high frequency signals and low frequency power between distant locations. At the sending end of the line a high frequency source is connected between the first and second wires by circuitry which prevents the low frequency power from being coupled into the high frequency source. A low frequency power supply is connected between the shield and both of the wires by circuitry which prevents the high frequency signals from being coupled into the low frequency supply. At the receiving end of the transmission line circuitry is provided which separates the high frequency signals from the low frequency power.

Abstract: As a scanning element of an electrophotographic copying machine begins to move, a feed roller moves a sheet of copy paper into the bite of register rollers which are held stationary. This movement of the copy paper is accomplished in a period of time which is less than that required for the scanning element to reach a predetermined scan synchronizing point. The feed roller is then stopped so that the copy paper is slightly buckled and thereby resiliently urged into the bite of the register rollers. When the scanning element reaches the scan synchronizing point, a sensor causes the register rollers to rotate thereby feeding the copy sheet through the machine in synchronization with the movement of the scanning element. The copy machine may employ a seamless photoconductive drum or belt moving at constant speed in which case an electrostatic image is formed on the drum or belt by the scanning element. The image is developed by toner particles and transferred to the copy sheet.