A pulse generator for feeding mass spectrometers

A small-size high-frequency rectangular alternating-voltage pulse generator is designed for energizing a cylindrical electrode of a monopole mass spectrometer. Amplitudes of positive and negative pulses linearly increase from zero to +150 V/?180 V for ～10 min and the frequency simultaneously linearly decreases from 2.0 to 1.4 MHz. A negative-polarity direct component, which is required for operation of the mass spectrometer, is formed due to unequal positive and negative amplitudes with respect to the ground. Spectra of residual gases with atomic mass numbers of 1–130 amu are obtained.     

A pulse magnetic-field generator for terahertz gyrodevices

A pulse magnetic-field generator producing pulse amplitudes up to 50 T with base durations of unities of milliseconds is described. The pulse magnetic field is obtained during discharging a capacitive storage through a thyristor-diode switch into a nitrogen-cooled solenoid. The repetition of the pulse amplitude of the current in the solenoid is ensured with an accuracy up to tenth of shares of a percent by stabilizing the precharge voltage of the storage and thermally stabling the solenoid. Using this generator, experiments for obtaining terahertz kilowatt-power radiation from 0.9- to 1.3-THz frequencies were successfully performed.     

A magnetic-thyristor pulse generator for electric-discharge technologies

A generator is described that is intended for operation in the area of electric-discharge technologies. Depending on the electrical strength of the load, the generator produces voltages of up to 50 kV, the dissipated energy of the pulse is up to 200 J, and the pulse repetition rate is up to 100 Hz. The generator is based on the direct discharge of capacitors to a discharge gap through a coaxial cable with a length of up to 200 m and without additional switching components. The circuit stabilizing the pulse energy due to recuperation of the unused energy in the filter capacitor of the power supply is used to stabilize the energy dissipated by the load.     

A high-voltage pulse generator for electric-discharge technologies

The electric circuit and design of a high-volta ge pulse generator with an output voltage of ≥3 50 kV is described. The generator operates in the nanosecond range of pulse durations (~300 ns) at a repetition rate of up to 10 pulses/s in a continuous mode and is intended for electric-discharge technologies. The energy stored in the generator is ~600 J, and the energy released in a pulse is ≥300 J. A discharge of a capacitive storage through a toroidal pulsed transformer and a discharge gap is used in the generator.     

Estimation of the strength and lifetime of technical objects using the acoustic-emission method

Estimation of the lifetime of a construction consists of forecasting the time remaining before failure and is based on extrapolation of the time dependences of the state parameters of a technical object to their critical values. The use for this purpose of simplified damageability models (e.g., a hypothesis of linear summation of flaws) and the absolute values of acoustic-emission (AE) parameters (e.g., activity, counting rate, duration of pauses) leads to a dependence of the estimate results on a large number of destabilizing factors and, as a result, to low accuracy or laboriousness of these techniques. An earlier suggested micromechanical model of AE parameters makes it possible to find a trade-off between simplicity and accuracy.     

A high-current pulse generator for gas discharge pumping

A generator has been designed for pumping a pseudospark gas discharge in xenon with the aim of generating UV radiation at a wavelength of 13.5 nm. The output parameters of the generator are as follows: the pulse energy is 10 J, the voltage is 6 kV, the peak current when short circuited is 40 kA, the base current pulse duration is 200 ns, and the frequency is as high as 500 Hz.     

A technique for testing and repairing the insulation of enameled wires

The principle of testing the enamel insulation of wires for flaws and a technique for flaw elimination by electrophoresis are presented.     

A current generator of the artificial lightning for full-scale tests of engineering objects

A powerful lightning current generator, which forms both individually its pulse (A), intermediate (B), long (C or C*), and repeated pulse (D) components of the negative (positive) polarity and their joint combinations in various unions, is described. Circuit and structural solutions are described that ensure (across a common active-inductive load) component A with an amplitude of no less than 200 kA and duration of up to 500 μs, component B with an average current of no less than 2 kA and duration of up to 5 ms, component C with an amplitude of no less than 800 A and duration of up to 1000 ms, component C* with an average current of 400 A and duration of up to 50 ms, and component D with an amplitude of no less than 100 kA and duration of up to 0.5 ms.     

A modular drift step-recovery diode generator for nanosecond pulse technologies

A generator of nanosecond pulses with an energy of ~50 mJ, which provides switching of voltage pulses with an amplitude of ~17 kV and a rise time of ~4 ns at a repetition frequency of 8 kHz to a 75-Ω resistive load, is described. The load is matched to the generator output cable. The generator is based on an opening switch in the form of a unit of drift step-recovery diodes (DSRDs). The conditions for the efficient operation of DSRDs are provided by six self-contained modules each of which contains an IGBT transistor and a step-up saturable-core transformer. The results of an experimental study of the generator are presented. They indicate a high efficiency of the developed modular circuit, which makes it possible to increase the switched energy virtually in proportion to the number of used modules, and the possibility of reducing the switching energy loss in the DSRD unit in proportion to the number of diode assemblies connected in parallel. It is shown that the generator can be used for producing ozone and high-purity silicon tetrafluoride and also in an apparatus for purifying air of organic pollutants.     

A compact repetitive high-voltage nanosecond pulse generator for the application of gas discharge

Uniform and stable discharge plasma requires very short duration pulses with fast rise times. A repetitive high-voltage nanosecond pulse generator for the application of gas discharge is presented in this paper. It is constructed with all solid-state components. Two-stage magnetic compression is used to generate a short duration pulse. Unlike in some reported studies, common commercial fast recovery diodes instead of a semiconductor opening switch (SOS) are used in our experiment that plays the role of SOS. The SOS-like effects of four different kinds of diodes are studied experimentally to optimize the output performance. It is found that the output pulse voltage is higher with a shorter reverse recovery time, and the rise time of pulse becomes faster when the falling time of reverse recovery current is shorter. The SOS-like effect of the diodes can be adjusted by changing the external circuit parameters. Through optimization the pulse generator can provide a pulsed voltage of 40 kV with a 40 ns duration, 10 ns rise time, and pulse repetition frequency of up to 5 kHz. Diffuse plasma can be formed in air at standard atmospheric pressure using the developed pulse generator. With a light weight and small packaging the pulse generator is suitable for gas discharge application.     

A method for increasing the sensitivity of X-ray testing of low-density objects

The effect of the electrical parameters of a power supply of an X-ray setup on the radiation intensity is considered. A method for increasing the sensitivity of X-ray testing is described.     

A pulse microwave generator for short-range radar-location and radio navigation systems

Special features of implementing a microwave generator based on 3A750 and 3A762 Gunn-effect diodes with a working frequency band of 8–12 GHz, an output power of 10–40 W, 56 × 56 × 36-mm sizes, and a working temperature range of ∼50°C are given.     

电火花加工脉冲电源功率器件的研究进展

功率器件是电火花加工脉；中电源中的一个核心元件，它对电火花加工的效率、加工精度和工具电极损耗等有很大的影响。本文综述了GTO、GTR、MOSFET、IGBT、MCT、IGOT和IPM等功率器件的研究现状和最新成果，并对它们在电火花加工脉冲电源中的应用与发展现状进行了分析评述。     

Electric strength of a vacuum gap during breakdown in an inhomogeneous electric field for switching high-power pulses

A system for matching the output of a multimodular plasma opening switch (POS) to a “liner”-type load having a small initial impedance is described. The main element of this system is an isolating spark gap that allows synchronization of the POS modules and prevents a repeated POS closure cutting off the inductive storage from the load. A spark gap based on a multigap explosive-emission diode, which was proposed and tested earlier, is insufficiently strong electrically to be used in the Baikal project aimed at the development of a superpowerful pulsed generator. An urgent problem of increasing the electrical strength of a 1-mm-wide vacuum gap, which is a basic element of the aforementioned spark gap, is being solved. It is proposed to use electrodes of the point (anode)-plane (cathode) type that allow the electric field to be concentrated at the point-type anode, thereby increasing the gap’s electrical strength. The results of experiments aimed at the study of vacuum breakdown in this system of electrodes are presented. It is shown that this design allows the gap’s strength to be raised by several times, a long service life of electrodes to be ensured thanks to the low energy-deposition density, and a multichannel (i.e., low-inductance) breakdown to be stably attained. A diagram of the spark-gap prototype is presented, its breakdown characteristics are obtained, and a full-scale scheme of the spark gap is presented.     

Nondestructive testing for flaws in the insulation of winding wires

Peculiarities of discharge that is initiated by a flawed section of wire insulation that passes through a primary gas-discharge flaw transducer have been studied. Analysis of the structure of signals has been carried out, and possible mechanism and type of discharge in the sensor have been considered. Informative zones have also been singled out in the signal structure. A technique is described for testing enamel-insulated wires for flaws. The technique makes it possible to determine the number and extent of flawed sections in an enameled wire that is fed through the system at any variable speed. Ways and means are considered for reducing the errors in evaluating the number and extent of flaws. Flow chart of a faultiness-measurement device is suggested, and the principle of its operation is described.     

A high-voltage nanosecond pulse generator for exciting diffuse gas discharges at atmospheric pressure

A high-voltage nanosecond pulse generator intended for studying diffuse discharges in gases at pressures close or equal to atmospheric pressure is described. The generator produces pulses with an ∼50-ns (at half-height) duration, a >50-kV voltage amplitude, a 10- to 12-ns rise time, and a pulse repetition rate of up to 1 kHz across an equivalent load (1.3 kΩ, 15 pF). The generator is based on available cheap components, and the amplitude (energy) of output pulses and their repetition rate can be promptly regulated in a wide range. The generator is immune to noise and reliable.     

A device for continuous remote monitoring of the electric strength of insulating oils

A device intended for testing the electric strength (ES) of insulating oil in electrical-engineering (electrophysical) equipment is described. The probe is a system of many identical electrode elements mounted with alternate polarities with a gap of 0.5 cm between them, so that all elements with the same polarity are connected in parallel. The total area of elements of the same polarity is >7000 cm². Before measurements of the ES, the experimental relationship between the current through an oil layer between electrodes and the liquid-breakdown voltage, which changed from 15 to 90 kV, was preliminarily determined at a potential difference U = 500 V between electrodes. Subsequently, the change in the current through oil at U = 500 V allowed evaluation of the breakdown voltage from the calibration curve. The promptness (several seconds) of remote ES measurements with the possibility of automating them according to a chosen program has been confirmed.     

A high-current plasma generator based on a hollow cathode for high-power electric propulsions

A construction diagram and procedure for independent tests of the new hollow cathode, created at the Keldysh Research Center, being capable of ensuring an emission current of about 100 A, and meeting the main requirements, imposed on thermoemission cathodes of high-power ion thrusters, are considered. Results of the independent tests are given and dependences of the discharge voltage on the discharge current in a discharge-current range of 20–120 A are obtained. The temperatures of the cathode construction elements in stationary operation modes are measured.     

A 1 MA, variable risetime pulse generator for high energy density plasma research

COBRA is a 0.5 Omega pulse generator driving loads of order 10 nH inductance to >1 MA current. The design is based on independently timed, laser-triggered switching of four water pulse-forming lines whose outputs are added in parallel to drive the load current pulse. The detailed design and operation of the switching to give a wide variety of current pulse shapes and rise times from 95 to 230 ns is described. The design and operation of a simple inductive load voltage monitor are described which allows good accounting of load impedance and energy dissipation. A method of eliminating gas bubbles on the underside of nearly horizontal insulator surfaces in water was required for reliable operation of COBRA; a novel and effective solution to this problem is described.