But a less obvious advantage is that an autotransformer provides a more constant output voltage under varying load conditions than does the two winding type of transformer.
Step up autotransformer example.
There are three types of auto transformers.
For performing the step up function the ac supply is connected to the variable tap point c b.
Step up autotransformer such kind of autotransformer s output voltage exceeds its input voltage vice versa for its current.
Variable auto transformers are used in the laboratory and industry to provide a wide range of ac voltages from a single source.
An autotransformer is an electrical transformer with only one winding the auto greek for self prefix refers to the single coil acting alone not to any kind of automatic mechanism in an autotransformer portions of the same winding act as both the primary winding and secondary winding sides of the transformer.
The autotransformer has a single winding on an iron core.
How to calculate power currents and voltage with a step up auto transformer.
Considered a step up transformer shown in the figure below.
The above figures show step up and step down autotransformers.
While the load is connected to the terminal a c as shown in the figure down below.
The core selection is similar to the procedure in step up autotransformer.
Note that because there is a common portion of the winding section 1 2 there is no isolation between the input and output circuits.
A step down autotransformer is to be designed with specifications like primary voltage of 230 volts secondary voltage of 110 volts output volt amp of 6 and output of 6 watts.
In contrast an ordinary transformer has separate primary and secondary.
Step up the obvious advantage of this type of transformer is that only one winding is needed.
Step up step down and variable auto transformers which can be either step up or step down the voltage.
Designing a step down autotransformer.
Also note that there is only one winding.
A simple autotransformer connection is shown in fig.
One of the coil terminals is common to both input and output and the other output terminal is movable so that it can make contact with any turn on the winding an autotransformer can be used as a step up or a step down transformer.