Autotransformer Advantages Disadvantages and Applications

Advantages of Autotransformer

1. As only one winding serves as primary and also secondary, there is a saving in winding material i.e copper saving.
2. Size is small.
3. Cost is lesser than two winding transformer.
4. very easy way of changing voltage.
5. Desired voltage can be obtained from fixed primary supply voltage hence suitable where variable voltage is needed.
6. As winding material is less, its resistance is less. I²R copper loss is less.
7. As loss is less, efficiency is higher.
8. Voltage regulation is also better.

Disadvantages of Autotransformer
Q. What are disadvantages of an autotransformer?

1. Primary and secondary are integral i.e. no isolation between them. This can prove to be not safe on high voltage operation.
2. If common portion breaks as shown in Figure
3. If secondary is shorted , large current is circulated which may damage insulation

Applications of Autotransformer
Q. Give the applications of autotransformer.
Applications of autotransformer

1. As a variac for changing the voltage for different purposes.
2. Dimmer-stat for dimming the lights in drarma theatres.
3. For furance to adjust the voltage.
   
4. For induction motor for stating at lower voltage as Autotransformer-starter.