Question:
A 60 W load is connected to the secondary of a transformer whose primary draws line voltage. If a current of 0.54 A flows in the load, what is the current in the primary coil? Comment on the type of transformer being used.
Solution:
Ps = 60 W
Is = 0.54 A
Primary voltage = 220 V
Vs = 60/0.54 = 110 V
The transformer is a step-down transformer as the voltage in the secondary is less than the voltage in the primary.
The transformation ratio is r = Vs/Vp = Ip/Is
Substituting the values we get,
Ip = 0.27 A