Contact Breaker Research Articles

Experimental and numerical approach to assess the dynamic performance of an inductive ignition system

This paper envisages studying the features of a conventional inductive ignition system along with its MOSFET and IGBT-based transistorized modifications. The influence of mechanical contact breaker dynamics and ignition coil characteristics on the current and voltage waveforms of the primary and secondary circuits of these studied ignition systems are mathematically and experimentally exposed. The investigation is considered necessary prior to attempting subsequent modeling and diagnostics procedures on the current-voltage performance characteristics of conventional and transistorized ignition systems. The work has demanded the development of an experimental setup based on a basic modifiable ignition system mockup and an instrumentation system to measure and analyze the voltage-current parameters of inductive ignition systems. The paper describes the design details of such instrumentation system, presents mechanical and electrical models for contact breaker and ignition circuits, then simulated to obtain base free-run response waveforms and electrical continuity behavior of the contact. A test of frequency response of the ignition coil provided additional input to the model. An experimental test of continuity of the contact, in agreement with its model, shed light on the actual excitation of the primary coil. The work comments on a sample of the registered current and voltage waveforms in primary and secondary coil windings of the ignition system at atmospheric conditions. Comparisons of waveforms and energy for mechanical contact, MOSFET and IGBT switches are made to establish them as a reference for future tests.

Control of Electronic Devices Using Smartphone-Based Voice Identification

This study aims to design the control system of an electronic device using voice identification-based smartphones generating electronic device control system. It optimizes the smartphone functions as a mobile phone than as a means of communication. The method used using the technique of direct observation by observing the success of the software AMR voice in identifying sound. In this design process smartphone as a sound receiver module, arduino as a controller, Bluetooth module as the sender and recipient of the data, and the relay as a contact breaker and connecting the electric current, as the output of LCD used to display information on whether the results of voice identification is correct or incorrect. Research tools electronic control device can control electronic devices such as fans, lamps and others depending on what is to be controlled. From the test results it can be concluded that the system control electronic devices by using voice identification-based smartphone that has been designed is divided into several parts, namely the Bluetooth module HC-05, arduino uno, relays and software AMR voice as a controller that has been tested to work and function properly.

Thermal, mechanical and tribological performance of polymer composites rubbed against polymer composites in application in electrical contact breakers

In this investigation, the thermal, mechanical properties and tribological performance of polyamide 6 composites filled up to 30 wt% mica is studied. The dry friction and wear tests of 30 wt% mica-filled polyamide 6 rubbed against 30 wt% mica-filled polyamide 6 and 30% glass fiber reinforced polyamide 6 polymer composite's discs were carried using a pin-on-disc test rig. Test's conditions were room temperature, applied load values of 20 N, 30 N and 40 N and at 0.5 m/s sliding speed. The results show an announced influence on mica content on the coefficient of friction and specific wear rate values of polyamide 6 composites. The results also show the influence of mica content on the mechanical properties, glassy transient temperature Tg and the melting temperature Tm of polyamide 6 polymer.

Tribological performance of industrial polyamide-imide and its composite under different cooling conditions

Abstract Polyamide-imide (PAI) polymer is a high-temperature resistant polymer, which is used as contact breaker material because of its high electrical insulation property. The working conditions of contact breakers arise from the wear and friction problem conditions of these materials. Therefore, the tribological behavior of PAI polymer is important. In this study, the friction and wear performance of pure PAI polymer and PAI composite [PAI+12% graphite+3% polytetrafluoroethylene (PTFE)] were studied in two different cooling environmental conditions (with and without air cooling). Wear tests were carried out with the configuration of a polymer pin, on a rotating AISI 316 L stainless steel disc. Test conditions were atmospheric conditions, 50 N, 100 N, and 150 N loads and 0.5, 1.0, 2.0 and 3.0 m/s sliding speeds. For sliding without air cooling and sliding with air cooling, the results show that the coefficient of friction and wear rates for pure PAI and PAI+12% graphite+3% PTFE composite, slightly decrease and increase with the increase in applied load and sliding speed values, respectively. In addition, for the range of loads and sliding speeds of this study, low coefficients of friction and high specific wear rates are registered at sliding under air cooling conditions. Finally, the wear mechanism includes adhesive and abrasive processes.

Scaling of Superconducting Switches for Extraction of Magnetic Energy

In certain cases it is necessary to extract the energy from a superconducting magnet when it quenches, in order to limit the heat generated by the event and thus prevent irreversible damage. This is usually achieved by opening a contact breaker across a resistor in the circuit feeding the magnet. For the heavy currents used to excite large magnets such switches incorporate sophisticated devices to limit arcing during the operation; the devices are reliable but are also bulky and expensive. It is interesting to consider the use of superconducting switches to perform this function, an important advantage being that they would be housed in the cryogenic environment of the magnet, and thus avoid permanent diversion of the current in and out of that environment to the mechanical switch (which operates at room temperature). However, practical switches for such an application are made up of superconductor in a metal matrix, and it is convenient to work with a relatively low resistance to approximate to the open circuit. This leads to scaling laws for superconducting switches for this application which relate the operating current and stored energy of the magnet system, the type of superconductor, and the necessary size of the device.

The switching life of short-circuit contact breakers in power systems

The switching life of short-circuit contact breakers in power systems

Friction and wear behaviours of some industrial polyamides against different polymer counterparts under dry conditions

PurposeThe present study aims to find out the best polymer/polymer pair in electrical insulating applications. Moreover, the effects of different polymer counterpart and applied load on the friction and wear behaviour of PA 46 + 30%GFR and unfilled PA 66 thermoplastic polymers are to be studied.Design/methodology/approachFriction and wear tests vs PA 46 + 30%GFR and PPS + 30%GFR polymer composites were carried out on a pin‐on‐disc arrangement and at a dry sliding conditions. Tribological tests were performed at room temperature under 20, 40 and 60 N loads and at 0.5 m/s sliding speed.FindingsThe results showed that, the coefficient of friction decreases with the increasing of load (up to 40 N) for PA 46 + 30%GFR composite and polyamide (PA) 66 polymer used in this study. However, above 40 N applied load the coefficient of friction increases. The specific wear rate for PA 46 + 30%GFR and PA 66 against PPS + 30%GFR polymer composite counterpart are about in the order of 10−13 m2/N while the specific wear rate for PA 46 + 30%GFR and PA 66 against PA 46 + 30%GFR polymer composite counterpart are in the order of 10−14 m2/N. For PA 46 + 30%GFR composite and unfilled PA 66 polymers tested the specific wear rate values increased with the increment of load. The highest specific wear rate is for unfilled PA 66 against PPS + 30%GFR with a value of 2.81 × 10−13 m2/N followed by PA 66 against PA 46 + 30%GFR with a value of 2.26 × 10−13 m2/N. The lowest wear rate is PA 46 + 30%GFR polymer composite against PA 46 + 30%GFR polymer composite counterpart with a value of 3.19 × 10−14 m2/N. The average specific wear rates for unfilled PA 66 against PA 46 + 30%GFR is 80 times higher than PA 46 + 30%GFR wear rate while specific wear rates for unfilled PA 66 against PPS + 30%GFR is 100 times higher than that of PA 46 + 30%GFR wear rate. From point view of tribological performance, PA 46 + 30%GFR is a more suitable engineering thermoplastic composite materials for electrical contact breaker applications.Research limitations/implicationsIn the present work, tribological tests were performed only at room temperature under three different loads and a sliding speed. This is the limitation of the work.Practical implicationsThis work is easily used for industrial polyamides to check their tribological behaviours.Originality/valueThis is an original and experimental study and it will be useful both for academicians and for industrial sides.

Dry sliding performance of thermoplastics against reinforced unsaturated polyester (BMC): In use in electrical contact breakers components

This work presents an experimental investigation of the wear and friction behaviours of reinforced thermoplastics in use in electrical contact breakers components. Sliding experiments were carried out on a pin-on-disc machine and under dry sliding conditions. The contact configurations used are polyamide 46 (PA46 + 30%GFR), polyamide 66 (PA66 + 30%GFR), polyoxymethylene (POM), polyphylenesulfide (PPS + 30%GFR) and aliphatic polyketone (APK) polymers pins against 15% long glass fibre reinforced unsaturated polyester (BMC) disc. The influences of applied load on the sliding wear behaviour of polymers were studied to decide the most suitable engineering polymer for contact breakers component in the electrical industry. The results showed that the coefficient of friction of the above polymers decreases linearly with the increase in load values. Furthermore, their specific wear rates increases with the increase in applied load values. The specific wear rate for APK, POM and PA66 + 30%GFR are in the order of 10 −8, 10 −8 and 10 −7 mm 3/N mm, respectively. The specific wear rates for PA46 + 30%GFR and PPS + 30%GFR are in the order of 10 −6 mm 3/N mm. Finally it is concluded that APK polymer is the most suitable engineering polymer for use in electrical contact breakers components.

Chromium-copper contact material for high voltage vacuum contact breakers: J. Qingshan et al, (Metallurgy Research Inst of Zhejiang Province, China), PM Technology, Vol 9, No 3, 1991, 156–160. (In Chinese)

Chromium-copper contact material for high voltage vacuum contact breakers: J. Qingshan et al, (Metallurgy Research Inst of Zhejiang Province, China), PM Technology, Vol 9, No 3, 1991, 156–160. (In Chinese)

Light barrier as contact breaker

Light barrier as contact breaker

A variable phase contact breaker for stroboscopic determination of waveform

The contact breaker described enables rapid phase variation by known increments so that quantitative examination of periodically varying phenomena can be carried out. The positive action reversible escapement used is considered in detail.

Magneto or Coil Ignition for Motor-Cars

F. R. HAIGH has recently compared the relative advantages of magneto and coil ignition used for generating the explosions which occur in motor-car engines (Students' Quart. J. Inst. Elec. Eng., Dec.). Coil ignition was prominent on the early types of petrol engines, but magnetos appeared on the market and for a number of years prior to 1914 a Bosch magneto was regarded as the acme of perfection. About ten years ago coil ignition systems came to the front. The magneto is of great importance in aero work and is popular on racing-cars, but in motor-vehicles it has been almost entirely replaced by coil ignition. Modern coil ignition systems are very trustworthy. The causes of the failure of the ignition system are almost always due to battery and wiring faults; they are very rarely due to the ignition apparatus itself. The contact breaker, coil and ignition switch are generally mounted at different points and thus their action is dependent on the soundness of the wiring between them. Loss of magnetism which used to cause trouble with magnetos is absent in coil systems. Ease in starting up an engine is a prominent feature in coil ignition; at whatever speed the engine is turning, a good spark is always obtained at the plug points. The contact breaker is usually the first component to be examined following an ignition failure, and hence its accessibility and ease of adjustment are of great importance. In this respect, coil ignition has nearly always the advantage. A clear view of magneto contact breakers can rarely be attained without the aid of a mirror. Coil ignition is also greatly superior to the magneto so far as the rapid replacement of faulty parts is concerned.

The performance of coil ignition systems, with particular reference to double contact-breakers and the effects of variation of the period of open circuit

The paper deals with experimental results obtained on a modern coil ignition system operated by a double contact breaker with a small angle of open circuit. At high speeds the contact breaker closes before the spark discharge ceases. Measurements of the effect of the persistence of the spark dicharge upon the coil performance for various secondary loading conditions are described. It is shown that the increase in the just-regularly-sparking output which is obtained is approximately independent of secondary loading due to normal values of shunted capacitance and/or resistance. A theoretical investigation, based on the results, is carried out to determine the approximate increase in sparking frequency with a given output, due to the effect of the persistence of the spark dischafge, for various periods of open circuit. Under certafa conditions, the estimated increase is 35 per cent for 0–4 millisecond and 63 per cent for 0-1 millisecond. The maximum sparking frequency of 12-volt coil systems, capable of meeting the output requirements of the Service specification for ignition apparatus, is estimated for various values of the open-circuit period. It is shown that the probable limit for reliable operation with a double contactbreaker is about 300 sparks per sec. per coil.

An accurate adjustable contact breaker

A revolving contact breaker is described which is capable of providing intervals (e.g. that of the passage of a constant current or that between two induction shocks) from 0.001 to 9 seconds. The driving power is derived from a gramophone motor, the speed of which from one winding is constant over about 100 revolutions, and is attained within one-eighth of a revolution starting from rest. Such an instrument was originally designed by the late Dr Keith Lucas, F.R.S., but has never been described. In a slightly modified form it has been found to be of the greatest use in physiological and other experiments.

The Wehnelt Current Interrupter

THE form of contact breaker recently introduced by Wehnelt is attracting so much notice, that it may be worth while to draw attention to an essentially identical arrangement described by Spottiswoode for use with an induction coil, more than twenty years ago (Proc. Roy. Soc., vol. xxv. p. 549). He says: “Another form of contact breaker was also occasionally used. The principle upon which it was based was the sudden disruption of a thin film of conducting liquid by a discharge between the electrodes of a circuit. The mode of effecting this was to make one electrode terminate in a platinum plate fixed in a horizontal position, and supplied with a uniform film of dilute sulphuric acid; the other in a platinum point, the distance of which from the plate is capable of delicate adjustment by means of a screw. Electro-motive force required for this break is not less than that of five cells of Grove. As soon as the current passes, the fluid between the plate and point will be decomposed, and electrical continuity broken. This done, the fluid flows back again, and continuity is restored. By a proper adjustment of the supply of fluid and of the distance between the electrodes (the latter varying from ˙05 to ˙001 of an inch), the number of disruptions may be made to attain 1000 per second. The currents delivered by this form of break are exceedingly uniform, and the effects produced are quite equal in delicacy to those produced by the electro-magnetic or by the wheel break.”

XXXII. A description of a contact breaker superior to any hitherto made, and of certain effects of a condenser on the action of various kinds of contact breakers

XXXII. <i>A description of a contact breaker superior to any hitherto made, and of certain effects of a condenser on the action of various kinds of contact breakers</i>