Energy Losses in Transformers

Transformers have energy losses due to four main factors--resistive loss, eddy current loss, hysteresis loss, and flux loss.

Resistive loss is the energy dissipated due to joule heating when current flows through copper coils that have significant resistance. It can be minimized by using thicker wires with low resistance.

Eddy currents result from varying magnetic fields in the iron core. They circulate throughout the core leading to heat losses. These losses can be decreased by using a laminated core made of insulated thin sheets. It makes eddy current paths narrower, reducing heat loss.

Hysteresis loss is due to repeated magnetization and demagnetization of the core by input alternating current. It is reduced by using a highly permeable magnetic core material.

Flux loss appears when the magnetic flux produced in the primary coil is not entirely linked to the secondary coil. A shell-type core can be used to reduce flux loss.

Energy losses affect the efficiency of a transformer, which is expressed as the ratio of output power to input power.