Copper loss is proportional to the square of load current. At half load, load current becomes half as voltage remains the same, so the copper loss will become (1/2)2 i.e 1/4 times of full load copper loss. At full load copper Loss = I2R At half load copper Loss = (I/2)2 × R = I2/4 × R 400 = I2/4 × R I2R = 4 × 400 I2R = Full load copper Loss = 1600 W
Galvanized steel conductors do not corrode, and possess high resistance. Hence such Wires are used in telecommunications circuits, earth wires, guard wire, stray wire, etc.
The reluctance of any part of a magnetic circuit may be defined as the ratio of the drop in magnetomotive force to the flux produced in that part of the circuit. It is measured in ampere-turns/Weber and is denoted by S. Reluctance = m.m.f ⁄ flux
In the above option, the wood has the lowest calorific value. Its value is around 17000 – 20000 kilojoule/kg. The calorific value of LPG is 55000 kilojoule/kg. The calorific value of Kerosene oil is 45000 kilojoule/kg. The calorific value of hydrogen oil is 150000 kilojoule/kg.
When variable loss becomes equal to the constant loss, efficiency is maximum. Losses = Pi + Pc Since copper loss is a variable loss therefore Losses = Pi + Pi = 2pi Thus at a maximum efficiency of this transformer total loss = 150 x 2 = 300 W
EXAMIANS