Answer / kishore

X(1 KVA) 50 HZ n Y(1 KVA ) 500 HZ
E = 4.44 f * FLUX * N
that is emf durectly proportional to flux which is f*B*A
B- flux density n A= area of c/s of transformer

as KVA reting of both are same n hence
X (f*B*A) = Y (f*B*A)
as frequency of X is smaller than Y so area of c/s of X
must be larger
hence 50 HZ transformer is largest and so on

kishoresahoo@ymail.com

Answer / bhanu(secure meters ltd.)

due to some mechanical constraints, generally transformer
size is inversely proportional to the operating frequency.

thus 50 hz, transformer will have max.size.

Answer / asutosh

with increase in frequency the size decreases so the 50 hz
will have big size
for better understanding refer high frequency transformers

Answer / ambi

this is a short cut method based on analysis..
generally power transformers use lower frequncy(50hz) and
we know in electronic ckts like oscillators producing very
high frqs in range of KHz we use only SMALL trfrs than pwr
trfrs.... so on analysing we can conclude tat higher
frquency transformers have less volume...
NOTE: this is only shrt cut mthd, actual reason depends on
the FORMULA only for determining the size

Answer / chankey garg

while increasing freq width of stamping decreases so 50hz
having bigest size

Answer / mohd shahid

bhai kishore see here we r talking about same KVA rating
not same KV rating.
here you r equting the KV rating(ie by equating the induced
emfs)
there is a diff between kv and kva hence kindly refer again
to your solution which acco. to me is not correct

Answer / rahul

The EMF of a transformer at a given flux density increases
with frequency.By operating at higher frequencies,
transformers can be physically more compact because a given
core is able to transfer more power without reaching
saturation and fewer turns are needed to achieve the same
impedance.

So, 50Hz transformer will be the bigger one.

Answer / r k alaria

The impedance of the transformer is greater for higher frequencies (as X=wL). So for constant voltage to keep same current rating (because for constant kVA)we have to reduce the inductance of the winding. And to reduce the inductance we have to reduce the no. of turns in the windings of the transformer. By reducing the no. of turns the size of the transformer will be reduced for higher frequencies.

Answer / engr. ziaul ashraf shafi

Mohd Shahid,
From the eqn V/F= flux, you wrote that "increasing the
frequency will cause the flux increasing. HOW ??

Answer / ganesh.m

Consider the primary of a transformer is operating at 230V,
50Hz. Consider the the secondary of the same transformer
generates 12V, 50Hz. What will happen to the secodnary
voltage, if the primary is fed with 230V,1KHZ supply?

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