Chapter 81

Question 0

A common use for a DC generator is:
A) a power supply for an elevator
B) an automobile alternator
C) power supply for a machinist lathe
D) power factor correction
E) computer room power supply

Answer 0

A) power supply for an elevator

Question 1

Alternators must run at constant speed in order to maintain:
A) current
B) power
C) voltage
D) resistance
E) frequency

Answer 1

E) frequency

Question 2

The yoke that supports the main components of the DC machine is frequently made of:
A) copper or brass
B) mica and carbon
C) copper and carbon
D) cast steel or iron
E) aluminum

Answer 2

D) cast steel or iron

Question 3

A rheostat is used to \_\_\_\_\_ the field strength in a DC machine.
A) stop
B) make
C) heat
D) vary
E) remove

Answer 3

D) vary

Question 4

In order to provide the strength of magnetic field required in large DC machines, stationary electromagnets call _________ are used.

Answer 4

Field poles

Question 5

Power is transferred to or from the rotor or armature commutator of a DC machine through carbon ____ mounted in insulated _____ load holders.

Answer 5

Brushes, spring

Question 6

A manual device that can be placed in series with the field of a DC generator to control output voltage by regulating current flow through the field is a ______.

Answer 6

Rheostat