Transformer losses and efficiency

 Transformer losses and efficiency

Transformer losses

There area unit generally 2 sources of losses in transformers on load, these being copper losses and iron losses.

(a) Copper losses

(a) Copper losses area unit variable and end in a heating of the conductors, because of the actual fact that they possess resistance. If R1 and R2 area unit the first and coil resistances then the overall copper loss is I^2 1R1 +I^2 2R2 

(b) Iron losses area unit constant for a given worth of frequency and flux density and area unit of 2 types—hysteresis loss and eddy current loss.

(i) Physical phenomenon loss/Hysteresis  loss

(i) physical phenomenon loss is that the heating of the core as a results of the interior molecular structure reversals that occur because the magnetic flux alternates. 

The loss is proportional to {the area unita|the world|the realm} of the physical phenomenon loop and therefore low loss nickel iron alloys are used for the core since their physical phenomenon loops have little areas.

(ii) Eddy current loss

(ii) Eddy current loss is that the heating of the core because of e.m.f.’s being iatrogenic not solely within the electrical device windings however additionally within the core. These iatrogenic e.m.f.’s created current currents, referred to as eddy currents. thanks to the low resistance of the core, eddy currents may be quite extensive and may cause an outsized power loss and excessive heating of the core.

 Eddy current losses may be reduced by increasing the ohmic resistance of the core material or, additional sometimes, by laminating the core (i.e., cacophonic it into layers or leaves) once terribly skinny layers of insulant may be inserted between every combine of laminations.

 This will increase the resistance of the eddy current path, and reduces the worth of the eddy current.

Transformer efficiency, 

and is typically expressed as a share. it's not uncommon for power transformers to possess efficiencies of between ninety fifth and ninety eight.