Electromagnetism and Transformers Quiz

___ is a force that acts at a distance and is caused by a magnetic field.

• Gravity

• Magnetism

• Permeability

• Reluctance

A strong, concentrated electromagnetic field is developed when a conductor is wrapped into a ___.

• coil

• linear field

• permanent magnet

• vacuum

___ is magnetism produced when electricity passes through a conductor.

• Electromagnetism

• Field magnetism

• Magnetic flux

• Magnetomotive force

The ___ determines if a device is a step-up or step-down transformer.

• number of coil taps on each coil

• number of transformer phases

• turns ratio between coils

• volts per turn

What is the turns ratio of an ideal 20 kVA, single-phase transformer with a 480-volt primary and a secondary full load current of 83.3 amps?

• 2 : 1

• 7.7 : 1

• 41.6 : 1

• 240 : 1

A transformer has a secondary voltage of 240V. The primary winding has 900 turns and the secondary has 90 turns. What is the value of the primary voltage?

• 60 volts

• 1350 volts

• 2400 volts

• 4800 volts

Electrical power circuits must be insulated by ___ where they enter the transformer tank.

• bushings

• coil taps

• copper

• fiberglass

In a balanced 3-phase, delta-connected system, the line current is equal to __ times the current in one of the coils.

• 0.58

• 1.00

• 1.73

• 2.33

Identify the primary transformer connection.

• Wye

• Delta

Identify the primary transformer connection.

• High Voltage

• Low Voltage