Question

Explain about the losses in Transformer?

Answer 1

A. As the Transformer is a static device mechanical losses do not come into picture. Transformer losses have two sources-copper loss and core loss. Copper losses are caused by the resistance of the wire (I2R). In primary side it is I12R1 and in secondary side it is I22R2 loss, where I1 & I2 are primary & secondary currents of transformer and R1 & R2 are resistances of primary & secondary winding. As the both primary & secondary currents depend upon load of transformer, copper losses vary with load. Core losses are caused by eddy currents and hysteresis in the core. Eddy current losses: In transformer we supply alternating current in the primary, this alternating current produces alternating magnetizing flux in the core and as this flux links with secondary winding there will be induced voltage in secondary, resulting current to flow through the load connected with it. Some of the alternating fluxes of transformer may also link with other conducting parts like steel core or iron body of transformer etc. As alternating flux links with these parts of transformer, there would be an locally induced  emf. Due to these emfs there would be currents which will circulate locally at that parts of the transformer. This type of energy loss is called eddy current loss of transformer. Hysteresis losses: The magnetic core of transformer is made of Silicon Steel, Steel is very good ferromagnetic material. The domains are arranged inside the material structure in such a manner, that net resultant magnetic field of the said material is zero. Whenever external magnetic field or mmf is is applied to that substance, these randomly directed domains arrange themselves in parallel to the axis of applied mmf. After removing this external mmf, maximum numbers of domains again come to random positions, but some few of them still remain in their changed position. Because of these unchanged domains the substance becomes slightly magnetized permanently. This magnetism is called “Spontaneous Magnetism”. To neutralize this magnetism some opposite mmf is required to be applied. For this reason, there will be a consumption of electrical energy which is known as Hysteresis loss of transformer. Hysteresis loss is constant for a particular voltage and current. Eddy-current loss, however, is different for each frequency passed through the transformer.

Answer 2

TRANSFORMER LOSSES - Transformer losses have two sourcescopper loss and magnetic loss. Copper losses are caused by the resistance of the wire (I2R). Magnetic losses are caused by eddy currents and hysteresis in the core. Copper loss is a constant after the coil has been wound and therefore a measurable loss. Hysteresis loss is constant for a particular voltage and current. Eddy-current loss, however, is different for each frequency passed through the transformer.