Difference Between Auto Transformer And Power Transformer

A transformer is an electrical device that transfers electrical energy from one circuit to another through electromagnetic induction. Power transformers and auto transformers are two types of transformers that are commonly used in power distribution systems. However, there are several differences between these two types of transformers.
Power transformer:
A power transformer is a type of transformer used to transfer electrical energy from a primary winding to a secondary winding. The primary winding is connected to the source of electrical power, whereas the secondary winding is connected to the load. This type of transformer is used to step up or step down the voltage level.
The power transformer consists of two coils, primary and secondary, which are physically separated and electrically insulated from each other. The voltage is transformed by the ratio of the number of turns of the two coils. For example, if the primary coil has 100 turns and the secondary coil has 500 turns, the voltage is stepped up by a factor of five.
Auto transformer:
An auto transformer, on the other hand, is a type of transformer that has a single winding that is used as both the primary and secondary winding. It is used to step up or step down the voltage level. In an auto transformer, a portion of the winding is shared by both the primary and secondary circuits. This is achieved by using a single coil with a tapping point along its length. The voltage is transformed by the ratio of the number of turns of the winding at different tapping points.
Difference between Auto transformer and Power transformer:
The main difference between an auto transformer and a power transformer is that an auto transformer has a single winding that is used as both the primary and secondary winding, whereas a power transformer has two separate windings for the primary and secondary circuits. The other differences are as follows:
1. Voltage regulation: An auto transformer has better voltage regulation than a power transformer. This is because the voltage regulation of a transformer is determined by the ratio of the number of turns of the primary and secondary coils. In an auto transformer, the turns ratio is closer to unity, resulting in better voltage regulation.
2. Cost: An auto transformer is less expensive than a power transformer, as it has a single winding. Power transformers, on the other hand, have two separate windings that increase the cost of production.
3. Impedance: A power transformer has a higher impedance than an auto transformer. This is because the two separate windings of a power transformer provide isolation and reduce the coupling between the primary and secondary circuits.
In conclusion, both auto transformers and power transformers are used for voltage regulation in power distribution systems. The choice between the two depends on various factors, such as the levels of voltage required, the cost of production, and the desired level of impedance. Overall, understanding the difference between these two types of transformers can help in selecting the appropriate transformer for a given application.