Question

What is an advantage to using an autotransformer connection and what is a disadvantage in using an autotransformer connection?

Answer 1

Advantages

1. Short Circuit Impedance of Autotransformer goes down with equivalent rating which in turn provides lower voltage drop and effective regulation.

2. The following things reduces

(a) equivalent power

(b) weight

(c) iron losses and cooper losses

Lets say if P is the power then, dimensions of auto transformer varies as P^0.25 and weight varies as P^0.75 .

Disadvantages

1. Sensitivity to atmospheric over voltages is more.

2. Short circuit current can ramp very high critical values.