Copper loss

From ArticleWorld

Copper loss is the term which is used to refer to the energy which is dissipated by the resistance in the wire used to wind a coil in an electrical device such as a transformer, motor or generator. Copper losses occur in electrical devices because of the flow of electrical currents through conductors. Copper losses increase as the value of electrical current passing through the conductors increases. An increase in the electrical resistance of conductors also causes the copper losses to increase.

In most transformers, the copper losses are usually about twice as much as the core losses which are caused due to eddy currents flowing in the core of the transformer. The copper losses in a motor or transformer can be calculated by using the formula: Copper loss = I-2 .R , where 'I' stands for the current which is flowing through the conductor and R stands for the resistance of the conductor.

Reduction of copper losses

Copper losses contribute to the reduction of efficiency in transformers, motors and generators. Hence it is necessary to cut down these losses in order to raise performance to optimum levels. Such losses occur in transmission lines as well, forming a major cause for the reduction in the efficiency of transmission over long distances. Copper losses are also manifest in the skin effect in transmission lines carrying alternating current, by virtue of which the outer 'skin' of a conductor allows current to pass rather than the inner layers.

Copper losses can be minimized by using conductors of large diameters in order to reduce the resistance per unit length of the conducting windings of the electrical device. The conductivity of a transmission line can be enhanced by using cables with multiple insulated conductors. Hollow conductors can also help reduce the cost of transmission.