EXERCISES
First requirement.
Multiple-choice
the loads must be balanced with 10
exercises 1 through
4 provide an
percent, and should be balanced
opportunity for you to
show that you
within 1 percent if possible.
To
understand the basic
principles of
what
degree
is
this
system
distribution
system
layout
and
balanced?
balancing.
a. 1%
c. 9.7%
b. 5%
d. 10.3%
1. If a break in the wires of a
radial
distribution
system
can
4. You
have
been
experiencing
result in the loss of power to a
difficulty with your generator, and
portion of the system, thereby
conclude
that
it
is
due
to
making
it
more
susceptible
to
Your 3 4W
unbalanced loading.
extreme
weather
conditions
and
generator
is
supplying
the
sabotage, why are radial systems
following loads:
preferred in TO construction over
1. 1 2W 1.2 KVA
other
systems
without
these
2. 1 2W 2.4 KVA
disadvantages?
3. 1 2W 3.6 KVA
a. require less material and time
4. 3 4W 10 KVA
to construct
5. 1 2W 2.4 KVA
b. have lower power losses than
6. 1 2W 1.2 KVA
other systems
c. are more easily adapted to a
Total = 20.8 KVA
wide variety of loads
d. are the easiest system to repair
Which of the following combinations
of loads on phases 1, 2, and 3
2. If
when
you
develop
your
respectively result in a balanced
wiring layout plan you find that
system?
some of the loads are more than
a. L1, 1/3 L4, L5; L2, 1/3 L4, L6;
1500 feet from the generator, what
L3, 1/3 L4
initial action should you attempt?
b. L1, 1/3 L4, L6; L2, 1/3 L4, L5;
a. select a larger generator to
L3, 1/3 L4
counteract the greater line loss
b. install a transformer between
c. L1, L2, L3; L5, L6; L4
the generator and these loads
d. 1/3 L3, L1, L4; L2, 1/3 L3, L5;
c. increase
the
wire
size
to
1/3 L3, L6
minimize the effect of distance
d. move the generator location to
Second requirement.
Solve multiple-
decrease the distance
choice exercises 5 through 8 to show
what you have learned about wire size
3. You are attempting to balance
and voltage drop determination.
the loads on the generator in a
three-phase system and find tem to
5. You plan to connect 3 4W
be distributed as follows: phase 1,
34.9KW; phase 2, 38.3KW; phase 3,
127/220V service directly from your
36.1KW. TO requirements state that
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