Question

Explain why transformer is the most efficient electrical machine?

Answer 1

Transformer is one of the most efficient device in electrical. The efficiency of transformer is greater than any other electrical machines. This is due to transformer is a static device and there is no any mechanical losses in transformers.

While if you say DC machine then there is a rotational part so their losses is greater than the transformer.

Now let's see how many losses are present in transformer and DC machine.

Losses in transformer-

1. Iron losses
   1. Hysterisis loss
   2. Eddy current loss
2. Copper loss( I^2*R loss)
3. Stray load loss

Now see the losses present in DC Machine-

1. Iron loss
   1. Hysterisis loss
   2. Eddy current loss
2. Copper loss
3. Stray load losses
4. Friction losses
   1. Friction between the bearing and the rotor.
   2. Friction between the carbon brushes and the commutator
5. Windage losses
6. Losses due to the sparking between the carbon brush and the commutator
7. The losses due to conversion between AC to DC and vice versa.