In electrical engineering there are several types of electrical transformers are use in power system. In the 3 phase auto transformer , there are two winding call primary winding and secondary wingdings. The main purpose of a general transformer is to step up or step down the voltage levels according to the requirements. Auto transformer are only consist one winding. But the performance of the auto transformer is same as general two winding transformers. Since there are one winding in auto transformer path of this winding is common to primary as well as secondary.
Working Principal of Autotransfomer
The working principle of an auto transformer is much similar to the performance of voltage regulator.
In the auto transformer, the primary and secondary wingdings are not insulate electrically and induction happens on self-induction.
In general two winding transformers, the primary winding and secondary wingdings connect only in magnetically.
But In this auto transformer, the primary and secondary connection are connected with electrical and magnetic ways.
Anyway the working principle of the auto transformer and conventional transformer are same. Both of them are work on the electromagnetic induction principle.
Applications of 3 phase auto transformer
These auto transformers are widely us in audio systems, electrical power transmission systems and also in railway systems.
When there is a voltage drop in distribution lines this auto transformers can use to correct the voltage drop inside the cable.
In squirrel cage induction motor, the starting need higher current so the voltage drop significantly. So these auto transformers are used to boost up the voltage when motor starting.
Mainly use for starting applications induction motors an synchronous motors.
Advantage of Auto transformer
The size of the autotransformer is small compare to the general transformer in same ratings so the manufacturing cost gets reduce and also the space to install also minimize.
Due to the size autotransformers are more economically benefits and also this transformer type is cheap compare with the general transformer.
3 phase auto transformer got great regulation compare with general transformers.
The leakage flux and resistant is a one of the minor loss in every transformer. This leakage flux and resistant of the autotransformer is very low compare with the ordinary transformer.
The general loss of this autotransformer also very less. So the efficiency is greater in this type of transformer.
Auto transformer got very less impedance compare with another type of transformers.
Disadvantages of Autotransformers
Compare to ordinary transformer this transformer need special protection on their insulations. Because auto transformer are much sensitive to the atmosphere .
Additional surge arrester protection is require for auto transformer.
The output voltage of autotransformer is variable and the output of general transformer is constant.
Primary winding of autotransformer not insulate on secondary side . So due to that when low voltage deliver from high voltage side secondary terminal become dangerous for load and for operator.
Hope that you have some good understanding on working principal, application , advantages and disadvantages of 3 phase auto transformer. We have already discuss several articles regarding transformers and plan to create lot of information regarding transformers in future.