Deck 14: Direct-Current Motor Principles

Question 1

The accompanying figure shows the torque graph for a single-loop armature.

Answer 1

False

Question 2

Describe two methods for increasing the torque produced by a single conducting loop in a direct-current motor.

Answer 2

The amount of torque, or turning force, developed by this single loop is directly dependent on the strengths of the field flux and the conductor flux. To strengthen the field flux, it is customary to use electromagnets for the field poles of a motor. To strengthen the conductor flux, the current in the wire must be increased.

Question 3

For a direct-current motor, one can apply the left-hand motor rule in order to determine the direction of conductor motion when the direction of the current is known.

Answer 3

False

Question 4

Explain why a single-loop armature has little practical value for commercial motor applications, and what can be done to address this problem.

Question 5

The amount of turning force generated by a conducting loop in a motor is known as the ____________________.

Question 6

In order to distribute the potential energy created through hydroelectric installations and the burning of coal and oil, these mechanical forms of energy must be converted to ____________________.

Question 7

In a direct-current motor, a current produces flux around all parts of the current-carrying loop. This is called ____________________ flux.

Question 8

In the accompanying figure, which shows a current-carrying conductor in a magnetic field, the current is traveling into the plane of the paper (away from you).

Question 9

The accompanying figure shows the torque-graph for a single loop armature. Draw or describe the orientation of the armature at each point where the torque reaches a minimum or maximum. Also, please explain why the armature continues to move through the point where the torque reaches a minimum.

Question 10

In a direct-current motor, the flux established by the permanent magnet is called the field flux.