-: Autotransformer :-
Auto Transformer is basically a one winding transformer and it is defined as -
" A kind of electrical transformer where primary and secondry share same common single winding coil is known as auto transformer ".
Construction and Working of Autotransformer :- In autotransformer one single winding is used as primary winding as well as secondary winding .
The winding AB of total turns 𝐍₁ is considered as primary winding , this winding is tapped from point C and the portion BC is considered as secondary having 𝐍₂ number of turns .
Efficiency of Autotransformer :- Autotransformer have higher efficiencies because in an autotransformer electrical power is transferred from primary to secondary partly by the process of transformation and partly by direct electrical connection . Therefore power conductively transferred produces no transformer loss .
Advantages of Autotransformer :-
1- An autotransformer uses less winding material than a 2-winding transformer .
2- An autotransformer is smaller in size and cheaper than the two winding transformer of the same output .
3- An autotransformer has variable output voltage when a sliding contact is used for the secondary .
4- Autotransformer has better voltage regulation as voltage drop in resistance and the resistance of single winding is less .
Disadvantages of Autotransformer :-
1- The leakage flux between the primary and secondary windings is small and hence the impedance is low .
2- It is more difficult to maintain the electromagnetic balance of the winding when voltage adjustment tapping are provided .
Applications of Autotransformer :-
1- The autotransformer is used as balance coil to give neutral in a 3 wire ac distribution system .
2- A continuously variable auto - transformer finds useful application in electrical testing laboratory .
3- Autotransformer are also used as boosters to raise the voltage in ac feeders .
4- Autotransformer with a number of tapping are used for starting induction motors and synchronous motors .
No comments:
Post a Comment