| 摘要 |
The invention relates to a source of reduced overall dimensions and mass, meant for supplying various auxiliary electrical services and for charging the battery of secondary cells on the tram, the source being supplied with 750 V DC, with a voltage variation usually of + 25 ... - 30%, to which there are added the atmospheric overvoltages. The direct current voltage entering the source, after passing through a network filter and a surge arrester (11), is converted inside an inverter with transistors (17 and 18), which gives a stabilized alternating output voltage which is then rectified in the rectifier with diode bridge (25, 26, 27 and 28) and filtered, there being obtained a stabilized direct current output voltage whose value depends on the temperature of the battery of secondary cells equipping the tram. The total current supplied by the source is limited to a maximum value irrespective of the loading, the source charging current being limited to an optimum value depending on the type and size of the battery, so as to obtain reduced values for the overall dimension and mass of the source. The converter is designed to the work in hard conditions of the tram, namely: high vibrations, wide temperature range of - 40 ... + 55 degree C. The output voltage is electrically insulated from the source input voltage.
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