Unit 6 - Quiz 1

Most electric motors operate through the interaction between _________________________ to generate rotary force within the motor.

• a motor's magnetic field and coil windings
• generators and inverters
• mechanical force and static electricity

Electric motors can be powered by direct current (DC) sources, such as from household electrical outlets.

• True
• False

Because it could store an electric charge, the “Leyden jar” was an early form of _____________.

• an electromagnetic motor
• a capacitor
• magnetism

The SI unit of measurement of electric current is called _____________________ .

• a capacitor
• a load
• the ampere

The Barlow wheel was an early demonstration of a direct current electric motor with two magnetic poles.

• True
• False

The periodically reversal of the current direction between the rotor and the external circuit is called _____________________________ .

• inertia of motion
• electromagnetism
• commutation

In a brushed DC motor, the axle is the stationary part of the motor and includes the motor casing as well the permanent magnets.

• True
• False

In a brushed DC motor, the rotor consists of copper windings, and the windings are electrically connected to the commutator.

• True
• False

A type of brushless DC motor that has the rotor outside as part of a rotating outer case while the fixed stator is located inside the rotor is called ___________________________.

• an AC motor
• a brushed DC motor
• an outrunner

Although previous magnets were made of ferrite, contemporary motors tend to use magnets made from ______________________ for their permanent magnets.

• mercury
• a Volta pile
• positive oxidation
• rare earth elements