Electrical Engineering - Transformers - Discussion
Discussion Forum : Transformers - General Questions (Q.No. 7)
7.
To step 110 V ac down to 20 V ac, the turns ratio must be
Answer: Option
Explanation:
Vp/Vs = Np/Ns
Vs = (Ns/Np)Vp
We required turns ratio i.e., (Ns/Np)
= Vs/Vp
= 20/110
= 0.181818182
[Note: p - primary; s - secondary]
For step down transfer, the turns ratio will be less than 1.
For simulation: Step-Down Transformer Circuit Simulator.
Discussion:
29 comments Page 3 of 3.
Che Lee said:
1 decade ago
The basic formula is
Vs/Vp = Ns/Np where: Vs secondary voltage 20 V
Vp primary voltage 110 V
Ns Secondary turns
Np primary turns
Using the formula gives
20/110 = Ns/Np
0.18 =Ns/Np Remember that turn ratio is Np/Ns
this will give:
Ans: Np/Ns = 5.5 A
* Note: Ns/Np may sometimes use in case of a step up transformer. In this problem it is a step down so Ns/Np is not consider.
Vs/Vp = Ns/Np where: Vs secondary voltage 20 V
Vp primary voltage 110 V
Ns Secondary turns
Np primary turns
Using the formula gives
20/110 = Ns/Np
0.18 =Ns/Np Remember that turn ratio is Np/Ns
this will give:
Ans: Np/Ns = 5.5 A
* Note: Ns/Np may sometimes use in case of a step up transformer. In this problem it is a step down so Ns/Np is not consider.
Darshan said:
1 decade ago
N2/N1 is correct N2=secondary turns, N1= primary turns.
Tanusri said:
1 decade ago
Can anyone tell me definition of turns ratio? is it N2/N1 or N1/N2 ?
Amit said:
1 decade ago
N2/N1=V2/V1.
N2/N1= 20/110.
0.18 Answer C.
N2/N1= 20/110.
0.18 Answer C.
J.khan said:
1 decade ago
Its so simple
V2/V1= 20/110
0.1818182 ans
Where
v2 Secondry voltage
v1 peri voltage
V2/V1= 20/110
0.1818182 ans
Where
v2 Secondry voltage
v1 peri voltage
Sushama said:
1 decade ago
My ans is 0.18.
Here,
Given data v1=110 v2=20
We know ratio=n2/n1
So,n2/n1=v2/v1
n2/n1=20/110 = 0.1818182
Here,
Given data v1=110 v2=20
We know ratio=n2/n1
So,n2/n1=v2/v1
n2/n1=20/110 = 0.1818182
Debraj said:
1 decade ago
I am confused.
It seems both are correct.
Please tell me the right ans and the right process.
It seems both are correct.
Please tell me the right ans and the right process.
K.Ashok kumar said:
1 decade ago
When i solved the problem i am getting 5.5v
given that v1=110,v2=20
we know,turns ratio means n2/n1
so n2/n1=v2/v1
n2/n1=(110/20)
n2/n1=5.5
given that v1=110,v2=20
we know,turns ratio means n2/n1
so n2/n1=v2/v1
n2/n1=(110/20)
n2/n1=5.5
Rajashekhar said:
1 decade ago
When I solved this problem am getting as 5.5 value. Kindly confirm me.
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