外文翻譯---負(fù)載運(yùn)行的變壓器-其他專業(yè)(參考版)
2025-01-23 09:45本頁面
【正文】 2V ,or (b) viewed from the secondary as a source of constant voltage 1V with internal drops due to 1Re and 1Xe . The magizing branch is sometimes omitted in this representation and so the circuit reduces to a generator producing a constant voltage 1E (actually equal to 1V ) and having an internal impedance jXR? (actually equal to 11Re jXe? ). In either case, the parameters could be referred to the secondary winding and this may save calculation time . The resistances and reactances can be obtained from two simple light load tests. 。2V to 2V .All calculations of internal voltage and power losses are made before this ideal transformation is applied. The behaviour of a transformer as detected at both sets of terminals is the same as the behaviour detected at the corresponding terminals of this circuit when the appropriate parameters are inserted. The slightly different representation showing the coils 1N and 2N side by side with a core in between is only used for convenience. On the transformer itself, the coils are , of course , wound round the same core. Very little error is introduced if the magising branch is transferred to the primary terminals, but a few anomalies will arise. For example ,the current shown flowing through the primary impedance is no longer the whole of the primary current. The error is quite small since 0I is usually such a small fraction of 1I . Slightly different answers may be obtained to a particular problem depending on whether or not allowance is made for this error. With this simplified circuit, the primary and referred secondary impedances can be added to give: 221211 )/(Re NNRR ?? and 221211 )/( NNXXXe ?? It should be pointed out that the equivalent circuit as derived here is only valid for normal operation at power frequencies。2 RR ? and 1239。 XX ? 。 . 239。2X and 39。 IENNINNEIEk V A ???? . The argument is sound, though at first it may have seemed suspect. In fact, if the actual secondary 7 winding was removed physically from the core and replaced by the equivalent winding and load circuit designed to give the parameters 1N , 39。 22 XI . The referred secondary 2212221222 )/()/(39。XI will be found to check as 39。39。 RNNR ? and 22212 )/(39。/39。39。 ENNE ? which is the same as 1E . For current, since the reaction ampere turns must be unchanged 1222 39。 2? , for example, by its demagizing action on m? has caused the changes on the primary side which led to the establishment of primary leakage flux. If a low enough leading power factor is considered, the total secondary flux and the mutual flux are increased causing the secondary terminal voltage to rise with load. p? is unchanged in magnitude from the no load condition since, neglecting resistance, it still has to provide a total bac
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