# A Single Phase Transformer Has 1000 Turns on the Primary and 200 Turns on the Secondary. the No Load Current is 3a - Basic Electrical and Electronics Engineering

Sum

A single phase transformer has 1000 turns on the primary and 200 turns on the secondary. The no load current is 3A at a power factor of 0.2 lag and the secondary current is 280A at a power factor of 0.8 lag. Neglect Rand X2 calculate (1) Magnetizing component and loss component of no load current. (2) primary current (3) input power factor .Draw phasor diagram showing all the currents.

#### Solution

I_P/I_S=N_S/N_P

Therefore, I_P=N_S/N_PxxI_S=200/1000xx280=56A

cosπ2=0.8 cosπ0=0.2 sinπ2=0.6 sinπ0=0.98
solve for horizontal and vertical components
πΌ1πππ π1=πΌ2πππ π2+πΌ0πππ π0 =(56×0.8)+(3×0.2)=45.4π΄
πΌ1π πππ1=πΌ2π πππ2+πΌ0π πππ0 =(56×0.6)+(3×0.98) = 36.54A
πΌ1=sqrt(45.4^2+36.54^2)=58.3π΄
π°π=π°ππππππ=(π×π.π)=π.πA

tanπ1 (36.54)/(45.4)= 0.805

ππ=ππ°
Power factor cosππ=πππππ°=π.ππ lagging.

Concept: Construction of Single Phase Transformer
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2018-2019 (December) CBCGS

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