LESSON 1
ELECTRIC POWER SYSTEMS
TEXT ASSIGNMENT -------------------- Attached memorandum.
MATERIALS REQUIRED ----------------- None.
LESSON OBJECTIVE ------------------- To teach you the characteristics
and functions of electric power
systems.
ATTACHED MEMORANDUM
1.
INTRODUCTION
3.
ALTERNATING CURRENT (AC) SYSTEMS
A reasonably reliable and adequate
Current
in
alternating
current
source of electric power is always
systems first flows in one direction
necessary
for
the
operation
of
around the loop, then reverses and
The required
flows
in
the
other
direction
at
standards of electric power systems
regular recurring intervals.
Most
generally
increase
proportionately
power systems are of the alternating
from the combat areas to the larger,
current type.
To understand how this
more permanent installations in the
type of current is produced, a simple
rear.
Maximum use should be made of
two-pole generator will be described.
existing
generating
equipment
and
Basically, this generator consists of
materials in order to save time and
a north and south magnetic pole and a
manpower.
Where no existing power is
loop of wire fixed so it can rotate
available,
portable
military
between the poles (fig 2).
generators capable of producing from
150 watts to 300 kilowatts are used in
a. Current induction.
As the loop
such combinations that there will
rotates between the poles a current
always be an adequate supply of power
is
induced
which
flows
in
when any one of them fails.
one direction when the first 180
degrees are being turned and in the
2.
DIRECT CURRENT (DC) SYSTEMS
opposite direction when the next 180
degrees
are
being
turned.
The
A direct current is a current which,
of
current
occurs
when
under the condition of a constant
the loop cuts the magnetic lines of
load, has a constant magnitude and
force flowing from the north to the
flows in the same direction at all
south pole. When the loop reaches the
times (fig 1). Use of DC current for
90-degree point, the maximum number
distribution
systems
is
not
of lines are being cut and the induced
widespread.
current is at a maximum.
When
1-1
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