Current transformer - Top Losses and Efficiency

Losses in transformers have been a bigger concern in power transmission and electrical engineering delivery. Where these losses can be largely defined as the difference between the power supplied at the input and the power supplied at the output. Since an electrical transformer is non-moving failure of the static unit by mechanical wear and tear. Losses in the transformer aren't the same as losses to a DC machine, while transformers have no mechanical losses.

There are presently two major losses in the transformer can be classified as follows:

Losses in eddy current and hysteresis of the transformer core construction depend on the magnetic materials. These losses are therefore called core loss of transformers.

Transformer Hytersis loss: This loss occurs as a result of the transformer's core reversal of magnetization property. Since this loss majority depended on the grade of iron and material volume, as the frequency of the reversal of magnetism and value depends on the density of the flux.

Transformer eddy current loss: An alternating magnetizing flux is set for any transformer Alternating current supplied to the transformer's primary winding input. It produces electromotive force when induced to secondary winding of the transformers by the magnetic flux. Metallic parts such as steel or iron core are associated with the flux induced. This results in an induced electromotive force in those metallic parts resulting in very less current flowing in them, known as eddy current. Which is responsible for the heat process energy dissipation.

Loss of Copper metal in transformer

A copper loss occurs mainly due to the transformer windings electrical resistance. Since the copper loss is I2R(1) for the primary windings, and the secondary winding is I2R(2). Whereas I1 is main winding current and I2 is transformer system secondary winding current. R(1) is also the electrical resistance of the transformer's main winding, and R(2) is the electrical resistance of the transformer's secondary winding. Since it is obvious that in the transformer the loss of copper metal is directly proportional to the current square where the amount of current transferred depends on varies with the load.

Transformer Efficiency

A transformer's efficiency purely depends on the supplied output power for the secondary winding to the transformer's supplied primary power. This principle does not only apply to any current or power transformer but also to other electrical devices. Whereas electrical devices are considered the most powerful transformers. Since most of these electrical machines or toroid transformer cores have a very full load efficiency of 90% to 95%. It is considered the same as the delivered output as being an extremely efficient machine supplied electricity. The calculation of transformer efficiency by output and input method is therefore very impractical.

Efficiency = (input - losses) / input = 1 - (losses / input).

Whereas its output can never be calculated by the requirement for maximum efficiency for some transformers. Let's assume the power transformer, for example, also energizes its primary windings each time. But for a secondary winding, as most of the day time, the power supplied to zero loads at very less charge. Because electricity use is often observed in residential areas during the night as contrasted with daytime use.

This is where secondary transformer never supplies any kind of load then only the transformer's core losses are considered to be the absence of copper losses. Copper losses for such transformers are known to be very low. As such transformers performance is only compared on the basis of the energy consumed per day.

Electronic Engineer at BEDO Innovating Education. Have contributed into the research and developement electronics and electrical devices. Also a contibuting writer for transformer and magnetic core industry.