Calculate the number secondary turns required. Collecting the information given the
question into usable form, have:
V
V
N
p
s
p
V
V
230
12
800
. symbols:
V
N
V
N
p
p
s
s
Where the primary voltage
Vs the secondary voltage
Np the number primary turns
Ns the number secondary turns
Moving the terms around, have general expression for transformer:
V
V
N
N
p
s
p
s
Vp Vs
Is
Ip
Primary
winding turns
Secondary
winding turns
Steel core
Magnetic circuit through core
FIGURE 10.Alternating current theory and electrical machines
213
described Faraday’s law, which says that when conductor cut a
magnetic field, emf induced that conductor.
Example
A 230V 12V emergency lighting transformer constructed with 800 primary turns. Since both windings
are linked the same magnetic flux, the induced emf per turn will the
same for both windings. Therefore, the emf both windings propor-
tional the number turns.21
A simple transformer.
Try This
Maths
Using the general equation for transformer given above, follow this maths
carefully, step step, the following example
