How does an auto transformer work in an electric machine

An auto transformer works by using a single winding to perform both the functions of a primary winding and a secondary winding. The transformer has a single winding that is tapped at different points to provide the necessary voltages and currents for the device.

When an AC voltage is applied to the input terminals of an auto transformer, a magnetic field is generated in the core of the transformer. This magnetic field induces a voltage in the winding, which is then transferred to the output terminals.

The amount of voltage transformation that takes place is determined by the ratio of the number of turns in the primary winding to the number of turns in the secondary winding. The voltage is stepped down or up depending on where the tap is taken on the winding.

In an electric machine, an auto transformer can be used for voltage regulation, to provide a variable voltage output, to step up or step down the voltage, and to provide isolation between two circuits. Auto transformers are commonly used in power supplies, motor control circuits, and other electronic devices.