Question

What are the different types of energy losses in a transformer?

Answer 1

Although transformers are very efficient devices, small energy losses do occur in them due to four main causes:

Resistance of windings – the low resistance copper wire used for the windings still has resistance and thereby contribute to heat lossFlux leakage – the flux produced by the primary coil may not be all linked to the secondary coil if the design of the core is bad.Eddy currents – the changing magnetic field not only induces currents in the secondary coil but also currents in the iron core itself. These currents flow in little circles in the iron core and are called eddy currents. The eddy currents cause heat loss. The heat loss, however, can be reduced by having the core laminated.(thin sheets of soft iron insulated from one another). (See image below)Hysteresis – The msgnetization of the core is repeatedly reversed by the alternating magnetic field. The repeating core magnetization process expends energy and this energy appears as heat. The heat generated can be kept to a minimum by using a magnetic material which has a low hysteresis loss. Hence, soft iron is often chosen for the core material because the magnetic domains within it changes rapidly with low energy loss.

Answer 2

Answer:

The energy losses in a transformer are as follows:

(i) Hysteresis loss : This is due to the repeated magnetisation and demagnetisation of the iron core caused by the alternating input current. This can be minimised by using alloys like mumetal or silicon steel.

(ii) Copper loss : Current flowing through the primary and secondary windings lead to Joule heating effect. Hence some energy is lost in the form of heat. Thick wires with considerably low resistance are used to minimise this loss.

(iii) Eddy current loss : Varying magnetic flux produces eddy current in the core. This leads to wastage of energy in the form of heat. This can be minimised by using a laminated core made of stelloy; an alloy of steel.

(iv) Flux loss : Flux produced in the primary coil is not completely linked with the secondary coil due to leakage. This can be minimised by using a shell type core.

Also, due to the vibration of the core, sound is produced, which causes a loss in the energy.