Question

A step down transformer converts a voltage of 2000 V inot 200 V in the transmission line. Number of turns in primary coil is 5000, efficiency of transformer is 80% and output power is 8 kW. Calculate input power and number of turns in secondary coil.

Answer 1

Here, `E_(P) = 2000 v, E_(s) = 200 V`,
`N_(P) = 5000, eta = 80%`
`P_(0) = 8 kW, P_(i) = ? N_(s) = ?`
From `eta = (P_(o))/(P_(i)) , P_(i) = (P_(o))/(eta) = (8)/(80//100) = 10 kW`
From `(N_(s))/(N_(P)) = (E_(s))/(E_(P))`
`:. N_(s) = (E_(s))/(E_(P)) xx N_(P) = (200)/(2000) xx 5000 = 500`