12. The demand factor is used to
c. 3 3W 208V
determine the amount of power that
d. 3 4W 120/208V
must actually be supplied to a
particular building.
What then is
Second requirement.
Solve multiple-
the generator factor used for?
choice exercises 9 and 10 to show what
a. it is the same as the demand
you have learned about generators.
factor
b. determining the amount of power
9. DC generators are seldom used
that must actually be supplied
since
the
voltage
cannot
be
to a group of buildings
increased or decreased by means of
c. taking into account that all
a transformer and the transmission
connected loads in a building
distance of DC power is limited.
are not used simultaneously
Why, then, might you need a DC
d. situations
where
the
demand
generator in a TO?
factor cannot be determined
a. short distance transmission of
emergency power
13. While
computing
the
load
b. production of 400 cycle current
requirements for a section of your
for radar equipment
installation,
you
group
four
c. backup for AC generators
buildings together and determine
d. power
for
a
the power that must be supplied to
network
them.
These buildings are: (1) a
50-man, 20' x 100' barracks; (2) a
10. The important characteristics
recreation hall 20' x 100'; (3) a
of a generator are its capacity or
15-ton 401 x 52' ice plant; (4) a
kilowatt (KW) rating, the voltage
60' x 140' machine shop.
What is
and frequency at which it operates,
the load you must be able to
and whether it is single or three
furnish
these
buildings
(the
phase.
Which
of
these
required generator capacity)?
characteristics determines the size
a. 104.2 KVA
c. 114.6 KVA
of the generator's driving motor?
b. 107.8 KVA
d. 129.8 KVA
a. capacity
b. voltage
Fourth requirement.
Multiple-choice
c. frequency
exercises 14 through 17 enable you to
d. number of phases
show
that
you
understand
the
principles of determining generator
Third requirement.
Multiple-choice
selection, availability, and location.
exercises 11 through 13 deal with load
estimation for electric distribution
14. The following generators are
systems.
available to you: three 100KW;
three 45KW; two 60KW; one 30KW; one
11. You are assigned the project
15KW.
You have determined the
of
determining
the
load
required generator capacity for a
requirements for a section of a
portion of your installation to be
proposed installation.
Among the
148KW.
Which of the following
buildings which must be served is a
generator combinations would you
2,500 man capacity laundry.
What
choose?
would you expect the demand load of
a. 2-60KW; 1-30KW
this laundry to be?
b. 2-100KW
a. 29.1 KVA
c. 36.1 KVA
c. 3-45KW
b. 32.5 KVA
d. 39.2 KVA
d. 3-100KW
1-17
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