What is the difference between isolation transformer and scott-T transformer?

Answer 1

An isolation transformer is used to electrically isolate the load from the power source and is a 1:1 ratio. This is done to prevent a fault on the load from affecting the generator and other loads.

A scott-T transformer is used to convert 3 phase AC to 2 phase or vice versa. Applications of this are voltage regulators or cost reduction for short distance 3 phase transmission. Using it for a voltage regulator you could run the 2 phase output through an inductor or capcitor and resistor branch to get a single phase indicative of all three phases of the output of a generator.