Electrical Engineering - Transformers - Discussion

Discussion Forum : Transformers - General Questions (Q.No. 4)
4.
If a transformer has 50 turns in the primary winding and 10 turns in the secondary winding, what is the reflective resistance if the secondary load resistance is 250 ?
250
25
6,250
62,500
Answer: Option
Explanation:
No answer description is available. Let's discuss.
Discussion:
46 comments Page 5 of 5.

Virendra ranpise said:   1 decade ago
Resistance ratio=R2/R1
Xmer ratio(K)=N2/N1
Where,
R1=Primary winding resistance
R2=secondary winding resistance
N1=Primari winding turns
N2=secondary winding turns
FORMULA FOR CALCULATING R1
R2/R1 = K square
i.e. R2/R1 = (N2/N1)square

250/R1 = (10/50) square
So
R1 = (250) / ((10/50) square)
R2=6250 ohm

Akshat gupta said:   1 decade ago
Where
n1=50
n2=10
r2=250ohm
so
resistance matching r1= (n1/n2)^*rl
hence,
r1=(50/10)^2*250
=25*250
=6250 ohm

S.ANJINEYULU NAIK said:   1 decade ago
Turn ratio, k=N2/N1.

=10/50.

=1/5=0.2.

Actual resistance in secondary circuit is R2=250 ohm's.

Reflective resistance means, the secondary resistance referred to primary winding is,

R2'=R2/k^2.

=250/ (0.2) ^2.

=250/0.04.

=6250 ohm's.

Mallikarjun said:   1 decade ago
R2' = r2/(kxk).
r2 = 250 ohms.

k = n2/n1 = 0.2.
(kXk) = 0.04.

R2' = 250/0.04 = 6250.

Yatish Ahire said:   1 decade ago
Primary resistance R1 = R2/(K)2.

Here,

K = N2/N1 = 10/50 = 0.2.

Hence,

R' = 250/0.2*0.2 = 6250 Ohm.

Ododo said:   1 decade ago
Please am confused, turns ratio is it the same as transformer ratio?

I saw that turns ratio = N2/N1, and I still saw that turns ratio = N1/N2, which one is correct with proofs please.


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