Electrical Engineering - Transformers - Discussion

Discussion Forum : Transformers - General Questions (Q.No. 2)
2.
The turns ratio required to match an 80 source to a 320 load is
80
20
4
2
Answer: Option
Explanation:
No answer description is available. Let's discuss.
Discussion:
101 comments Page 8 of 11.

Saheb said:   1 decade ago
R(hv) = K^2*R(lv).

[v2/v1 = k,i2*r2/i1*r1 = k, R(hv)/R(lv) = k^2; k = 2; r2/r1 = k^2].

Krishnakumar said:   1 decade ago
During current loss test (short circuit) we had applied rated current of the transformer. Transformer reaches its rated current at some voltage. It is very low current loss only depend on voltage. So it is negligible.

Rangaswamy M.D said:   1 decade ago
v2/v1 = i1/i2.
= v1/r1*r2/v2.
(v2/v1)^2 = r2/r1.

(k)^2 = r2/r1.
k^2 = 320/80.
k^2 = 4 .
k = 2.

Pal said:   1 decade ago
N(s)/N(p) = E(S)/E(p)-1.

I(p) N(p) = I(s) N(p).

E(P) N(P) / R(P) = E(S) N(S)/R(S)-2.

From 1 and 2.

Sq (N(S)/N(P)) = R(s)/R(p).

Reshma said:   1 decade ago
I m not satisfy this answer.

Turn ratio = E1/E2 =V1/V2 =N1/N2=1/k.

GAUTAM said:   10 years ago
Clearly given in question that:

Primary or source resistance R1 = 80 ohm.

Secondary resistance R2 = 320.

We know that:

Transformation ratio k = N1/N2 = V1/V2 = R2/R1 = I2/I1.

SO K = 320/80 = 4 is correct answer.

Chandrashekar said:   10 years ago
320 = n^2*80.

n^2 = 320/80 = 4.

n = 2.

Hanumantha HK said:   9 years ago
Above all guys discussed ok but there is a mistake in that !

Turns ratio(n) = N1/N2 =V1/V2 = I2/I1.
Same Transformer ratio is (K) = 1/n.

Means V2/V1 = N2/N1 = I1/I2 = K.

The question is Turns Ratio ?
V1*I1=V2*I2.
(v1)^2/R1= (V2)^2/R2.
So (V1/V2)^2=R1/R2.

Turns ratio n = (N1/N2)^2=R1/R2=80/320=1/4.

When we make sqrt it will come = 1/2.

What you guys are saying the above solution ?

Amjad moawia said:   9 years ago
No! @Hanumantha Hk.

The correct law is : vs/sp = NS/NP = IP/IS.

Please, revise once again.

Sudha said:   9 years ago
Can anybody solve this problem in a simple way?


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