24 Electrical Power Systems Technology
or line. The object has a mass of 150 kg and is moved 28 meters in 8 sec-
onds.
Find: The power developed by the motor in watts and horsepower
units.
Solution:
Force (F) = 9.8 × mass
= 9.8 × 150 kg
F = 1470 newtons
Work (W) =F × d
=1470 × 28 m
W = 41,160 joules
Power (P) = W/t
= 41,160/8
P = 5,145 watts
P
Horsepower = ——, since
746
1 horsepower = 746 W.
hp = 5,145/746 = 6.9 hp
The Electrical Power System
A block diagram of the electrical power systems model used in this
textbook is shown in Figure 2-4. Beginning on the left, the first block is
Electrical Power Measurement. Power measurement is critical to the effi-
cient operation of electrical power systems. Measurement fundamentals
and power measurement equipment are discussed in Unit I of this text-
book. The second block is Electrical Power Production. Unit II presents
the electrical power production systems used in our country. Once elec-
trical power has been produced, it must be distributed to the location
where it is used. Electrical Power Distribution Systems are discussed in
Unit III. Power distribution systems transfer electrical power from one
location to another. Electrical Power Conversion Systems (Unit IV), also