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
Discussion:
46 comments Page 1 of 5.
Mahendra chauhan said:
1 decade ago
# given data primary coil turns=50,secondary coil turns=10 & secondary load 250 ohm.
#equation N=secondary coil turns/primary coil turns
(Rpri=reflected in to primary)
Rpri=(1/n)^2*RL
so N =10/50
=0.2
Rpri =(1/0.2)^2*250
=(5)^2*250
=25*250
=6250.
#equation N=secondary coil turns/primary coil turns
(Rpri=reflected in to primary)
Rpri=(1/n)^2*RL
so N =10/50
=0.2
Rpri =(1/0.2)^2*250
=(5)^2*250
=25*250
=6250.
Abhishek mohapatra said:
8 years ago
From the basics:
You have to find what resistance on primary will have similar effect as 250 on secondary.
in ideal transformer power associated with primary equals secondary hence V2^2/250 = v1^2/Rreq. similarly V2*I2 =V1*I1. if you know what voltages are related in the same way as a number of turns i.e V2/V1 = N2/N1 then you can easily relate all currents and impedances.
You have to find what resistance on primary will have similar effect as 250 on secondary.
in ideal transformer power associated with primary equals secondary hence V2^2/250 = v1^2/Rreq. similarly V2*I2 =V1*I1. if you know what voltages are related in the same way as a number of turns i.e V2/V1 = N2/N1 then you can easily relate all currents and impedances.
Eshan Mishra said:
1 decade ago
There is difference b/w the terms if simply turn ratio, voltage ratio is mention and transformation ratio is mention in the question.
Eg:- transformation ratio is k, k=[V2/V1=N2/N1=I1/I2].
Simple turn ratio, voltage ratio is equal to 1/k
N1/N2, V1/V2.
And there is one more important relation,
(V2/V1)=Square root(R2/R1).
Eg:- transformation ratio is k, k=[V2/V1=N2/N1=I1/I2].
Simple turn ratio, voltage ratio is equal to 1/k
N1/N2, V1/V2.
And there is one more important relation,
(V2/V1)=Square root(R2/R1).
Akash.bhure said:
1 decade ago
Solution:
No.of turns in the primary(N1) = 50.
No.of turns in the secondary(N2) = 10.
Turns ratio(K) = N2/N1 = 10/50 = 0.2.
Secondary load resistance(R2) = 250 Ohm.
Reflective resistance(R1) = R2/K^2.
(R1) = 250/(0.2)^2.
(R1) = 250/0.04 = 6250 ohm's.
No.of turns in the primary(N1) = 50.
No.of turns in the secondary(N2) = 10.
Turns ratio(K) = N2/N1 = 10/50 = 0.2.
Secondary load resistance(R2) = 250 Ohm.
Reflective resistance(R1) = R2/K^2.
(R1) = 250/(0.2)^2.
(R1) = 250/0.04 = 6250 ohm's.
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
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
Santosh murkut said:
9 years ago
The transformation ratio is said that N2/N1 = V2/V1 = I1/I2 = K.
Hence,
1) A resistance R1 in primary become K^2 * R1 when transferred to the secondary.
2) A resistance R2 in secondary become R2 / K^2 when transferred to the primary.
Therefore,
R1 = 250 / (10/50)^2 = 6250 ohm.
Hence,
1) A resistance R1 in primary become K^2 * R1 when transferred to the secondary.
2) A resistance R2 in secondary become R2 / K^2 when transferred to the primary.
Therefore,
R1 = 250 / (10/50)^2 = 6250 ohm.
Sanjeev Kr. Rajoria said:
1 decade ago
Transformation ratio a = N1/N2
so
a=50/10=5
now
load resistance referred to primary= (a^2)*(load resistance)
so
the reflected load = 5^2*250
= 25*250
= 6250 ohm
So the correct ans is (c)= 6250 ohm
so
a=50/10=5
now
load resistance referred to primary= (a^2)*(load resistance)
so
the reflected load = 5^2*250
= 25*250
= 6250 ohm
So the correct ans is (c)= 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.
=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.
Suresh said:
4 years ago
Voltage of secondary 200v, transformer ration N1:N2= 200:100, X=12 Ohms and Rl = 4 Ohms.
Estimate the RMS value of the primary current I1 and Secondary Current I2 and Estimate the power in watts.
Estimate the RMS value of the primary current I1 and Secondary Current I2 and Estimate the power in watts.
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.
I saw that turns ratio = N2/N1, and I still saw that turns ratio = N1/N2, which one is correct with proofs please.
Post your comments here:
Quick links
Quantitative Aptitude
Verbal (English)
Reasoning
Programming
Interview
Placement Papers