There are three basic types of transformers used to supply the correct power and voltage to the motor. Single phase transformer, auto
transformer and three phase transformer.
An autotransformer is utilized when a low ratio of high to low voltage is required; also,
for its versatility and economics. Each phase has one continuous winding with taps at various points on the winding.
that has three single phase transformers wound on a single core and set in a case is considered a three phase transformer. The high
voltage windings that surround the low voltage windings are separated by insulation to prevent flashover. The iron core is normally
inside the low voltage windings.
The transformer most commonly found in the oil field is the single phase transformer. It is used for
higher voltage and higher ratio applications. Each transformer has two windings and an iron core. Normally each application requires
three single phase transformers to complete a bank, necessary to operate a submersible pump.