Investigations of transients in the device of forced control of the vacuum contactor monostable electromagnet
Journal Title: Вісник Національного технічного університету "ХПІ". Серія: Проблеми удосконалювання електричних машин і апаратів. Теорія і практика - Year 2018, Vol 32, Issue 1308
Abstract
A review of systems of forced control with buster and holding windings is carried out. It is found that there is a large number of various systems of forced control of electromagnets. It has been established that in the contactors systems of forced control with buster and holding windings are most often used. The advantages and disadvantages of such systems of forced control are considered. It has been discovered that the most commonly used forced control device for monostable electromagnets consists of two coils with two windings: buster (B) and holding (H), and a normally closed contact of the auxiliary contact block, as well as a diode rectifier, a diode and a capacitor. Such a device is widely used by many leading manufacturers of vacuum contactors such as: ABB, Siemens, Alstom (Areva), Schneider Electric, Eaton, Electrodynamics, etc. Experimental studies of transients in one of the switching devices - the vacuum contactor in which this device is used, namely, the serial threepole vacuum contactor КВТн-250/1,14 produced by Electrodynamics Company are carried out. Two series of experiments were conducted: the first series of experiments was conducted for the existing system of forced control, and the second series of experiments - for a forced control system in which the diode was shortened, the anode and cathode of which were connected with the ends of the retaining windings, respectively, of the first and the second coils of the electromagnet. The research was carried out using a digital two-beam oscilloscope SIGLENT SDS1052. The oscillograms of current and voltage in the buster and holding windings are obtained at various voltage values U = 220, 180, 150 V, and when powered from a source of constant voltage, and then from a source of alternating voltage. The analysis of experimental research is carried out. The advantages and disadvantages of the forced control device are revealed. It is revealed that the switching device (vacuum contactor КВТн-250/1,14) will not operate at an unacceptable voltage drop, which will lead to overheating of the coil, and it will fail. The conclusions are made and possibilities of perfec-tion of the forced control device for monostable electromagnets are shown.
Authors and Affiliations
O. G. Korol, B. V. Klymenko, O. V. Eresko
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