. Theory and calculation of alternating current phenomena . t OEo, while the difference of phase in the primary cir-cuit is found to be 00 = EoOFo. 24. Thus, in Figs. 18 to 20, the diagram of a transformer isdrawn for the same secondary , E^, secondary current, /i,and therefore secondary , Fi, but with different conditionsof secondary phase displacement: VECTOR REPRESENTATION 29 In Fig. 18 the secondary current, /i, lags 60° behind the sec-ondary , El. In Fig. 19, the secondary current, /i, is in phase with the sec-ondary , El. In Fig. 20 the secondary current, /i, lead
. Theory and calculation of alternating current phenomena . t OEo, while the difference of phase in the primary cir-cuit is found to be 00 = EoOFo. 24. Thus, in Figs. 18 to 20, the diagram of a transformer isdrawn for the same secondary , E^, secondary current, /i,and therefore secondary , Fi, but with different conditionsof secondary phase displacement: VECTOR REPRESENTATION 29 In Fig. 18 the secondary current, /i, lags 60° behind the sec-ondary , El. In Fig. 19, the secondary current, /i, is in phase with the sec-ondary , El. In Fig. 20 the secondary current, /i, leads by 60° the El. These diagrams show that lag of the current in the secondarycircuit increases and lead decreases the primary current and pri-mary impressed required to produce in the secondary circuitthe same and current; or conversely, at a given primaryimpressed , Eo, the secondary , Ei, will be smallerwith an inductive, and larger with a condensive (leading current),load than with a non-inductive load. Ei-*. At the same time we see that a difference of phase existing inthe secondary circuit of a transformer reappears in the primarycircuit, somewhat decreased, if the current is leading, and slightlyincreased if lagging in phase. Later we shall see that hysteresisreduces the displacement in the primary circuit, so that, with anexcessive lag in the secondary circuit, the lag in the primarycircuit may be less than in the secondary. A conclusion from the foregoing is that the transformer is notsuitable for producing currents of displaced phase, since primaryand secondary current are, except at very light loads, very nearlyin phase, or rather in opposition, to each other. CHAPTER V SYMBOLIC METHOD 25. The graphical method of representing alternating-currentphenomena affords the best means for deriving a clear insightinto the mutual relation of the different alternating sine wavesentering into the problem. For numerical calculation, how
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