(Solved): 4. a) Explain the difference between efficiency and regulation in a transformer. State the transfo ...

4. a) Explain the difference between efficiency and regulation in a transformer. State the transformer parameter that most influences efficiency and regulation. [3 marks] b) An ideal transformer draws 4.8 A from a 240V, 50Hz supply connected to the primary. If the secondary current is 62.4 A, determine the turns-ratio N1/N2 and the secondary voltage. [3 marks] c) A transformer has a turns-ratio of 8 and its primary is connected to a 240V, 50Hz supply. Figure 4c shows the simplified equivalent circuit in which the magnetizing branch has been moved to the primary terminals. The transformer parameters, which are all referred to the primary are as follows: LM = 0.68H, 111 112 = 12mH, R? = 122, R? = 32 (i) Determine the magnitude of the magnetizing current Im. [2 marks] (ii) A 692 (actual value) resistive load is now connected to the secondary. Determine the magnitude of the primary current I? [5 marks] (iii) Determine the efficiency of the transformer under this operating condition. [4 marks] 3 EEEE1028 R? R? 1? 1? mm mw 240V 50Hz Im Lm m R?