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The purpose of this paper is to investigate a reliable evaluator of arc re-ignition and to develop a numerical tool for accurate prediction of arc behaviour of low-voltage switching devices (LVSDs) prior to empirical laboratory testing of real products.

Two types of interruption tests have been carried out in the investigation of re-ignition evaluators. Arc modelling tool coupled with the load circuit has been developed to predict arc characteristics based on conventional magnetohydrodynamics theory, with special attention given to Lorentz force acting on the arc column and surface phenomena on the splitter plate. The model assumptions have been validated by experimental observation of arc motion and current and voltage waveforms.

It is found that the exit-voltage across the switching device and the ratio of system to exit-voltage at the current zero point are reliable evaluators for prediction of re-ignition. Where the voltage ratio is positive, instantaneous re-ignition does not occur. Further, the probability of re-ignition is very low if the voltage ratio is in the rage of −1.3 to 0.

It is observed that the voltage ratio can be considered as a reliable global evaluator of re-ignition, which can be used for various types of LVSD test conditions. In addition, it is shown that arc modelling allows a good prediction of the current and voltage waveforms, arc motion as well as the exit-voltage, which can be used to obtain the evaluator of re-ignition.

WITH the introduction of airborne wireless equipment it became apparent, even with the low frequency and voltage ignition systems which were then used, that the prevention of radio interference caused by the ignition impulses presented a problem of considerable proportions. As engine development was pursued it was observed that the use of higher ignition voltages and frequency resulted in more efficient combustion; today high voltage and frequency ignition systems involving the use of oscillatory circuits are a common feature in piston‐engined aircraft.

IN consequence of the rapid progress in aircraft development in the past decade it has been necessary for cable manufacturers to provide an ever‐widening variety of cables to meet the special needs of aircraft designers.

Burndept Electronics (E.R.) Ltd. is now marketing a homing instrument for fixed or rotary wing aircraft which, when used with the company's SARBE personal and flotation beacons or similar equipment, gives a ground/air range of 150/200 miles at 30,000 ft. (60/80 miles at 10,000 ft.). It will pick up any radio distress signals on 1215 MHz (VHF) or 243 MHz (UHF). Trial orders have already been received from the U.K. Ministry of Defence and the Chilean air force.

The research purpose of this paper is to confirm that internal overvoltages in the push–pull power inverter can be used to improve the discharge ignition in the gliding arc discharge (GAD) plasma reactor.

Investigations are based on the acquisition of voltage changes that occur together with the development of the discharge column and the imaging the GAD with the use of a high-speed camera.

The power supply has the distinctive feature of not having the switching overvoltages completely extinguished, as it is in typical push–pull inverters. The overvoltages still exist but only dangerous peaks are cut off. The remaining ones, of a dumped resonance character (Figure 3), are transferred to the secondary coil of the transformer. Correctly shaped overvoltages are used for ignition improvement in the GAD reactor.

GAD plasma reactors have many applications for pollution control, disinfection and sterilization of surfaces and for plasma deposition, surface functionalization, as well as in agricultural and medical treatment. Investigations prove the push–pull inverter’s advantages in comparison with the transformer-type power supply. Properly configured push–pull inverters have good ignition properties and control options, allowing to generate, desirable for many applications, homogeneous non-thermal plasma.

The idea of using switching overvoltages in transistors of push–pull switching-mode power supplies is new and has not been previously used to improve discharges ignition in a non-thermal plasma reactor.

The purpose of this paper is to investigate power performance, economy and hydrocarbons (HC)/carbon monoxide (CO) emissions of diesel fuel on a two-stoke direct injection (DI) spark ignition (SI) engine.

Experimental study was carried out on a two-stroke SI diesel-fuelled engine with air-assisted direct injection, whose power performance and HC/CO emissions characteristics under low-load conditions were analysed according to the effects of ignition energy, ignition advance angle (IAA), injection timing angle and excess-air-ratio.

The results indicate that, for the throttle position of 10%, a large IAA with adequate ignition energy effectively increases the power and decrease the HC emission. The optimal injection timing angle for power and fuel consumption is 60° crank angle (CA) before top dead centre (BTDC). Lean mixture improves the power performance with the HC/CO emissions greatly reduced. At the throttle position of 20%, the optimal IAA is 30°CA BTDC. The adequate ignition energy slightly improves the power output and greatly decreases HC/CO emissions. Advancing the injection timing improves the power and fuel consumption but should not exceed the exhaust port closing timing in case of scavenging losses. Burning stoichiometric mixture achieves maximum power, whereas burning lean mixture obviously reduces the fuel consumption and the HC/CO emissions.

Gasoline has a low flash point, a high-saturated vapour pressure and relatively high volatility, and it is a potential hazard near a naked flame at room temperature, which can create significant security risks for its storage, transport and use. The authors adopt a low volatility diesel fuel for all vehicles and equipment to minimise the number of different devices using various fuels and improve the potential military application safety.

Under low-load conditions, the two stroke port-injected SI engine performance of burning heavy fuels including diesel or kerosene was shown to be worse than those of gasoline. The authors have tried to use the DI method to improve the performance of the diesel-fuelled engine in starting and low-load conditions.

The purpose of this paper is to present the design and optimization of a comparator with two transistors.

The effect of back‐gate bias in MOSFET is analyzed and applied to a comparator circuit in a flash‐type A/D converter (ADC). The 4‐bit flash ADC is simply structured by change of comparator block based on CMOS latch with pMOSFET switch. The back‐gate bias on MOSFET changes the threshold voltage and provides for a CMOS inverter to shift the voltage transfer characteristics. In the new type comparator, the variation of turn‐on voltage is controlled within 0.1 V in 4‐bit ADC. The fabrication is done in a 0.35 μm single‐poly four‐metal process.

Layout simulation shows that INL is within 0.3 LSB and SNDR is 25.4 dB at input frequency of 20 KHz and sampling rate of 4 MS/s. The 0.26 × 0.43 mm 2 ADC dissipates 1.2 mW at supply voltage of 3.3 V.

A comparator which uses the effect of the back‐gate bias on MOSFET is applied to a flash ADC. The paper is of value in showing how the circuit of this comparator is quite simple compared with a conventional comparator based on a CMOS latch, which is adaptable for a low‐power analog circuit in future. The experimental output of the 4‐bit flash ADC shows a good agreement with a simulation. Power consumption 1.2 mW, INL 0.2 LSB, and SNDR 25 dB are obtained in the simulation study.

Three different active power filter (APF) configurations are developed for harmonic elimination of a three‐phase electric arc furnace (EAF). Three single‐phase APF, a three‐wire APF and a four‐wire APF are developed for this purpose. A predictive control method of the APFs based on dynamic programming method is applied and the results of the simulation studies are compared. Finally the stability of the system is analyzed and its global asymptotic stability is shown.

This paper aims to provide an overview of current and historical arcjet development. The reviewed arcjets are considered with respect to both design and thruster relevant parameters. Correspondingly, the paper enables the identification of adequate design criteria and of the probable thruster parameters.

The approach consists of a database for thruster relevant parameters in conjunction with relevant operational requirements (such as type of propellant) and specific design criteria (such as e.g. propellant injection systems).

The synopsis of both operational parameter and respectively assigned design allows for the derivation of development approaches for arcjets under given high level requirements such as power regime.

The paper is a general review. However, its strength is in the synthesis of the arcjet classification, the functional evidence of design criteria and the application scenario.

Not only basic but also specific design criteria are analyzed and evaluated leading to a recommendation feature of the paper with respect to the overall design of adequate arcjets.

Within the scope of the Clean Space initiative, new applications and scenarios from the operation of arcjets arise enabling EOL phases of spacecraft that fulfill respective levels of debris mitigation and, in addition, the requirements concerning the adequately adapted re-entry of spacecrafts that are at end of life.

The paper is a general review. However, its strength is in the synthesis of the arcjet classification, the functional evidence of design criteria and the application scenario.

This paper aims to overcome the limitations of low efficiency, low power density and strong electromagnetic interference (EMI) of the existing pulsed melt inert gas (MIG) welding power supply. So a novel and simplified implementation of digital high-power pulsed MIG welding power supply with LLC resonant converter is proposed in this work.

A simple parallel full-bridge LLC resonant converter structure is used to design the digital power supply with high welding current, low arc voltage, high open-circuit voltage and a wide range of arc loads, by effectively exploiting the variable load and high-power applications of LLC resonant converter.

The efficiency of each converter can reach up to 92.3%, under the rated operating condition. Notably, with proposed scheme, a short-circuit current mutation of 300 A can stabilize at 60 A within 8 ms. Furthermore, the pulsed MIG welding test shows that a stable welding process with 280 A peak current can be realized and a well-formed weld bead can be obtained, thereby verifying the feasibility of LLC resonant converter for pulsed MIG welding power supply.

The high efficiency, high power density and weak EMI of LLC resonant converter are conducive to the further optimization of pulsed MIG welding power supply. Consequently, a high performance welding power supply is implemented by taking adequate advantages of LLC resonant converter, which can provide equipment support for exploring better pulsed MIG welding processes.