Transformer Instant Review

Transformer: Transformer is static machine use to Transfer the Electrical Power through magnetically from one circuit to another by without changing frequency.

Efficiency of transformer is about 96 to 98%. Which is much high as compare to another electric machine. Because it is static machine hence it didn`t have Friction and Windage losses.

EMF induced in primary circuit is approximate equal to the EMF induced in secondary winding. EMF is induced due to flux linkage between primary winding and secondary winding. Frequency of flux is same as frequency of applied voltage. Transformer is generally used to step up and down the voltage and current.

Working Principle: Transformer works on Faraday's law of Electromagnetic induction. Which state that if variable flux link with any conductor then emf will induce into it. The magnitude of emf induced is directly proportional to the rate of change of flux. According to LENZ's law the direction of induced emf is such that it will oppose the cause of production of it.
Hence from above equation we came to know that frequency and are of transformer is inversely proportional. If frequency will increase then the size of transformer will decrease.

Transformer magnetic circuit is made up of laminated iron core to provide Low reluctance path for flux.

Silicon steel laminations are stacked together to form the core. Lamination is done to reduce to eddy current loss. Thicknesses of lamination are around (0.35mm to 0.5mm).

CRGO (cold rolled grain oriented silicon steel) is used to make core of transformer as it has small area of hysteresis loop and have high value for saturation of flux. It offers high permeability to the flux. Hence decrease Hysteresis loss.

Condition for maximum efficiency of Transformer: Copper losses = Iron losses