|Class 12 Physics Alternating Current||Types of Transformers|
Types of Transformers
There are 2 types of transformers:-
Step up transformer:-
Step down transformer:-
Problem:- A power transmission line feeds input power at 2300V to a step down transformer with its primary windings having 4000 turns. What should be the number of turns in the secondary in order to get output power at 230V?
Input voltage , Vp = 2300V
Number of turns in primary coil, Np =4000
Output voltage, Vs = 230V
Number of turns in secondary coil, Ns
Using (Vp/Vs) = (Np/ Ns)
(2300/230) = (4000/ Ns)
Ns = (4000 x 230)/(2300)
Hence there are 400 turns in the secondary coil.
Problem:- At a hydroelectric power plant, the water pressure head is at a height of 300m and the water flow available is 100 m3 s−1. If the turbine generator efficiency is 60%, estimate the electric power available from the plant (g =9.8 m s−2 ).
Height of water pressure head, h = 300 m
Volume of water flow per second, V = 100 m3/s
Efficiency of turbine generator, n = 60% = 0.6
Acceleration due to gravity, g = 9.8 m/s2
Density of water, ρ = 103 kg/m3
Electric power available from the plant = η × hρgV
= 0.6 × 300 × 103 × 9.8 × 100
= 176.4 × 106 W
= 176.4 MW