Exam 12: Transformers

A transformer's audible hum is a result of the laminations and windings vibrating as the magnetic field alternates.

If a transformer's primary winding has 200 turns and the secondary winding has 600 turns, the turns ratio is ____.

The efficiency of a transformer may be as high as ____ percent.

When transformers are constructed, the windings are often placed on separate legs to minimize flux leakage.

A(n) ____ is used for installations where heavy loads are used infrequently or where it is apparent that future demand may require additional loading.

The type of material from which the core is made affects the efficiency of the transformer.

The coils of an air core transformer are wound on forms made of nonconducting materials.

Small transformers, such as those used for doorbell and signal circuits, are usually very efficient.

The molecular motion caused by the magnetizing and demagnetizing of a transformer's core results in friction which produces heat. This heat loss plus the power loss caused by the magnetic lag is called the ____ loss.

If a transformer increases the voltage, it is called a ____ transformer.

If a transformer has a ratio of 10 to 1 (10:1), it is being used as a(n) ____ transformer.

Air core transformers are ____.

What is one method of cooling a transformer?

Transformers used for power distribution are wound on cores made of ____.

One method of transformer construction is to build up thin, flat sections called ____.