What makes a transformer efficient?

[infamous_Q]

what makes one efficient? ie...does frequency have anything to do with it, operating temperature, number coils, core material, etc.

 

[Adrian Baker]

Key factors are:
- Low resistance copper wires in the coils
- High permeance core material (Iron) to give a large Flux
- laminated core to prevent eddy currents in the core
- Core material with low hysterisis

 

[infamous_Q]

so frequency doesnt' matter that much? and what do you mean by laminated? and also, does iron have low hysterisis? oh, and is it possible to switch the wires your using later in the circuit (ie. go from like 10 gauge to 18 guage, assuming it the power can be handled in that form by both)?

 

[Adrian Baker]

Eddy currents are induced currents at going across the core (not round it). As P=I^2*R then any current leads to an energy loss. The core is therefore made of thin laminates of 'soft' iron so that a current can't run across the core.

'Soft' iron has low hysterisis for general use such as 50-60HZ supply.

The greater the csa of the wires used, the lower the resistance, so the less heat lost there.