The features of dry-type transformers: they transmit AC while isolating DC, and can simultaneously achieve voltage transformation, impedance transformation, and phase transformation. The individual windings of dry-type transformers are not interconnected, but AC electricity can be transmitted through magnetic coupling.

The function of a dry-type transformer: voltage transformation, impedance transformation, and phase transformation. The magnitude of the secondary voltage of a dry-type transformer depends on the ratio of the turns of the secondary winding to the primary winding. When no load is applied, the ratio of the secondary voltage to the primary voltage is equal to the ratio of the turns of the secondary winding to the primary winding.

Dry-type transformers also serve as impedance transformers. The ratio of the number of turns in the primary and secondary windings of a dry-type transformer is different, resulting in varying coupled impedances. Numerically, the ratio of the secondary impedance to the primary impedance is equal to the square of the ratio of the number of turns in the secondary winding to the number of turns in the primary winding. Dry-type transformers also have the function of phase transformation. By changing the connection method of the windings in a dry-type transformer, it is convenient to invert the voltage signal.