Factors that affect the efficiency
The heating effect of current in a coil.
Power is lost as heat I2R whereby I is the current flowing through the coil and R is the resistance of the coil

Methods to increase the efficiency
Use thick copper wires of low resistance. Use coolant to decrease the temperature of the transformer.

Heating effect of induced eddy currents
In the iron core. When the magnetic field in the iron core fluctuates, eddy currents are generated in the iron core.

Methods to increase the efficiency
Use a laminated iron core whereby each layer is insulated with enamel paint to prevent the flow of eddy currents. The high resistance between layers of the iron core decrease the prevalence of eddy currents and heat.


Magnetization of the iron core.
The energy used in the magnetization and de-magnetization of the iron core each time current changes its direction is known as hysterisis. This energy is lost as heat which subsequently heats up the iron core.

Methods to increase the efficiency
Use a soft iron core that is easily magnetized and de-magnetized.

Flux leakage.
Some of the induced magnetic flux from the primary coil is not transmitted to the secondary coil, therefore the e.m.f in the secondary coil is decreased.
The secondary coil(windings) are intertwined tightly with the primary coils. The iron core should form a closed loop.

Methods to increase the efficiency
The secondary coil (windings) is intertwined tightly with the primary coils. The iron core should form a closed loop.

3 comments

  1. asyiqin // April 21, 2009 at 9:19 PM  

    what is the significant of using the laminated iron core?

  2. Sek // May 5, 2009 at 8:39 AM  

    As written above, the core is laminated to reduce eddy current.

  3. neonhermit // April 19, 2012 at 2:34 AM  

    Isn't there a problem with using thicker wires, since they allow for less resistance, and thus the current is proportionally greater, and since power loss involves current^2, wouldn't this just increase power loss?

    Also, does the number of coils you wrap around affect the efficiency (i.e if I were to wrap 100 around primary, and 200 around the secondary, would it transfer power more efficiently if I wrapped 300 around the primary and 600 around secondary instead?) Thats what seemed to happen when we used a transformer experimentally