The correct answer is: B. Saving in winding material
An autotransformer is a type of transformer that uses only one winding to transfer power from one circuit to another. This results in a saving in winding material, as only one winding needs to be manufactured and installed.
A two-winding transformer, on the other hand, uses two windings to transfer power. This means that twice as much winding material is required, which can lead to a significant increase in cost.
In addition to the saving in winding material, autotransformers also offer a number of other advantages over two-winding transformers. For example, they are typically smaller and lighter, and they can be more efficient.
However, autotransformers also have some disadvantages. For example, they can only be used to step up or step down voltage by a certain amount, and they can be more susceptible to noise and interference.
Overall, autotransformers offer a number of advantages over two-winding transformers, including a saving in winding material. However, they also have some disadvantages that should be considered before selecting one for a particular application.
Here is a brief explanation of each option:
- Option A: Hysteresis losses are reduced. This is not necessarily true for autotransformers. In fact, hysteresis losses can be higher in autotransformers than in two-winding transformers, because the core of an autotransformer is subjected to a wider range of magnetic flux densities.
- Option B: Saving in winding material. This is the main advantage of an autotransformer over a two winding transformer. As mentioned above, an autotransformer uses only one winding to transfer power, while a two-winding transformer uses two windings. This results in a saving in winding material, as only one winding needs to be manufactured and installed.
- Option C: Copper losses are negligible. This is not necessarily true for autotransformers. Copper losses are the losses that occur in the windings of a transformer due to the resistance of the wire. These losses can be significant in both autotransformers and two-winding transformers.
- Option D: Eddy losses are totally eliminated. This is not true for any type of transformer. Eddy losses are the losses that occur in the core of a transformer due to the eddy currents that are induced in the core by the magnetic flux. These losses can be reduced by using a laminated core, but they cannot be totally eliminated.