5.
● Alternatively, reducing the number secondary turns will reduce the
output voltage.
FIGURE 5.18. Large power transformers, used electri-
cal distribution systems, can have efficiency better than 90%. sketch oil immersed transformer can be
seen Fig.
Try This
Have you seen any transformers action?
Were they big small what were they being used for?
Have you been close transmission tower, perhaps when you were walking
in the countryside?
.Basic Electrical Installation Work
116
● alternating voltage applied the primary winding establishes an
alternating magnetic flux the core.
● The voltage both the primary and secondary windings propor-
tional the number turns. This has application power
distribution.
Large power transformers need cooling take the heat generated away
from the core.
● The magnetic flux the core causes voltage induced the
secondary winding the transformers. Equipment
supplied from SELV source may installed bathroom shower-
room, provided that suitably enclosed and protected from the ingress
of moisture.
VP VS
IS
IP
Primary
winding turns
Secondary
winding turns
Steel core
Magnetic circuit through core
FIGURE 5.18
Typical oil filled power transformer. This often achieved totally immersing the core and
windings insulating oil. This includes equipment such water heaters, pumps for
showers and whirlpool baths.17
A simple transformer. Small trans-
formers are used isolating transformers shaver sockets and can also
be used supply separated extra low voltage (SELV) sources.
● This means that you increase the number secondary turns you
will increase the output voltage.
Very small transformers are used electronic applications. Because has moving parts, transformer can
have very high efficiency. This useful for low voltage supplies such domestic
bell transformers
