Deck 17: Dc Motors

Question 1

A ____ motor has a very high starting torque.

A) series
B) shunt
C) combination
D) permanent magnet

Answer 1

A

Question 2

A(n) ____ is a type of rotating switch.

A) stator
B) prony brake
C) armature
D) commutator

Answer 2

D

Question 3

Arcing at the brushes may be the result of _____.

A) improper voltage
B) a dirty commutator
C) loose parts
D) a dirty lubricant

Answer 3

B

Question 4

____ motors are designed to be used for jobs requiring minimum torque.

A) Series
B) Brushless DC
C) Stepping
D) Permanent magnet

Question 5

In a brushless DC motor, a special circuit is used to perform the commutation of the applied DC.

Question 6

When using the right hand rule for a motor, the thumb points in the direction of the ____.

A) current
B) field
C) force
D) lines of magnetic flux

Question 7

The starting torque of a shunt motor is about ____ times the full-load torque.

A) 1.75
B) 2.00
C) 2.75
D) 3.00

Question 8

An instrument designed to measure torque is called a ____ .

A) rotational force meter
B) torquometer
C) torque wrench
D) prony brake

Question 9

In some types of DC motor arrangements, a flywheel assists the motor in driving the load.

Question 10

Overheated bearings may be the result of _____.

A) improper voltage
B) a dirty commutator
C) loose parts
D) a dirty lubricant

Question 11

A good commutator will have a very dark brown film of oxide.

Question 12

One application of a phototransistor is a(n) _____.

A) optical encoder circuit
B) voltage regulator
C) Hall-effect device
D) voltage controller

Question 13

Because the armature of a DC motor is wound in much the same way as a DC generator, the current from the supply must divide and flow through three or more paths.

Question 14

The operation of a motor depends upon the interaction between ____ magnetic fields.

A) two
B) three
C) four
D) six

Question 15

Insulation tests are a type of motor maintenance task that should be performed on a regular basis.