Electrical Engineering - Transformers - Discussion

Discussion :: Transformers - General Questions (Q.No.19)


To step 120 V ac up to 900 V ac, the turns ratio must be

[A]. 75
[B]. 750
[C]. 7.5
[D]. 0.13

Answer: Option C


No answer description available for this question.

Abby Joseph said: (Dec 15, 2010)  
Here V1 is 120, V2 is 900 so

Ahmed Al Rawas said: (May 20, 2011)  
Why shouldn't be N1/N2 = v1/v2

thus, N1/N2 = 120/900 = .133

isn't that right ??

Ambrish said: (Jul 7, 2011)  
Yeah my doubt is also same ?

Murugaperumal said: (Aug 10, 2011)  
It is step up transformer so,

Pruthvi said: (Aug 15, 2011)  
Is turns ratio different for step up and step down transformer?

Mahijagadeesh said: (Sep 2, 2011)  
Turns ratio means the ratio of primary turns to secondary turns is it wrong?

But why in this problem took reverse.

Yogesh Sabota said: (Nov 4, 2011)  
I agree with Mahijagadeesh
this answer is incorrect
It should be 0.13v

Asim Juneja said: (Jan 22, 2012)  
N2/N1 is transformation ratio while,
N1/n2 is turns ratio,
thus my perception says correct ans. is 0.13

Mahesh Pakki said: (Mar 26, 2012)  
Guys ... please remeber for

step down transformer , turns ratio < 0

Step up transformer , turns ratio > 0 ..

In this question .. its step up .. hence turns ratio should be greater then zero ..

Sirisha said: (May 24, 2012)  
Turns ratio=N1/N2. (step down).
Turns ratio=N2/N1. (step up).
If not mentioned the type of tx by default consider step up.

Amarjyoti Sarmah said: (Aug 15, 2013)  
Is turns ratio different for step up and step down transformer?

N2/N1 is transformation ratio while,

N1/N2 is turns ratio, Is not it right. I am very much confused. Please help me?

Naveed said: (Oct 20, 2013)  
The ratio of a four-to-one step-down transformer is written as 4:1.The ratio of a one-to-four step-up transformer should be written as 1:4. Notice in the two ratios that the value of the primary winding is always stated first.

Rajan India said: (Mar 16, 2015)  
Turns ratio k = v2/v1.

Here, k = Turns ratio of transformer.

v2 = Secondary voltage of transformer.

v1 = Primary voltage of transformer.

Vicky said: (Jan 3, 2016)  
Turns ratio means ratio of high voltage side to low voltage side turns.

Stuti Kushwaha said: (Feb 16, 2016)  
Please help me that where we can use n1/n2 and where we can use n2/n1?

Mehaboob Nadaf said: (Mar 20, 2016)  
N2/N1 = V2/V1.
900/120 = K=7.5.

San said: (Mar 24, 2016)  
Is it same for V2/V1, R2/R1 & I1/I2?

Raghuvamsi said: (Apr 29, 2016)  
Yes, @Ahmed.

The answer should be 0.13.

Here the problem is asking turns ratio, not transformation ratio.

Ramesh said: (Jun 16, 2016)  
Finally, what is the correct answer?

Ajit said: (Nov 22, 2016)  
Yes, I agree the answer is 0.13.

Sanjay Patil said: (Nov 24, 2016)  
Yes, Agree with the answer 0.13.

Because N2/N1= V2/V1= I1/I2 it is transformation ratio and N1/N2 is Turn Ratio.

Teja said: (Jun 20, 2017)  
Turns ratio is primary to secondary. So the answer is wrong.

Aditya Singh said: (Apr 14, 2018)  
Yes, the answer should be 0.13.

Ankita Mali said: (Dec 23, 2018)  
What is the final answer? Please tell me.

Shivam said: (Sep 29, 2019)  
Answer will be 0.13.

Because turn ratio is inverse of transformation ratio.

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