Answer / mondo

When the secondary of a CT is open circuited, it creates a
very large voltage across the CT. That is why if there is
no burden on the CT, it should always be shorted.

Answer / solanki

one of my frnd says rite that there produced a very high
voltage across the secondary of ct.but from where its
produced no one told.
as all of we know that
E1/E2=I2/I1
FROM THERE E2=E1*I1/I2
BUT IF WE KEEP SECONDARY OPEN THEN I2=0
E2 BECOMES INFNITY

Answer / shashi

If secondary is opened while primary wdg carrying current, then secondary MMF reduce to zero while primary MMF is same.Consequently, the resultant MMF which is equal to primary MMF(as secondary MMF is zero)is very high and it will induce very large flux in the core till core saturates and when this flux links with secondary winding a very high voltage will be induced in secondary wdg .So,
1) This high voltage can breakdown the insulation of secondary wdg.
2) High voltage may even cause fatality to operator who opened the secondary wdg.
3) High resultant flux in core will cause high eddy current loss and hystersis loss .Thus, transformer will get overheated and damage permanently.
4)The high flux will make core permanently magnetised .So, residual flux will introduce error in measuring device.

Answer / shyamsundar nayak

Because there is hevy voltage in secondary........

Answer / yasmina

CT genarally rated as x/5A,orx/1 A as x value depends upon
full load current, CT Volt amp ( rated VA)is constant on
both primary and secondary ,if you kept open the Secondary
a large value of volatge build up and it is hozordious to
equipment around it and operation people.

Answer / mit

> if the secondary of C.T. is open then the secondary mmf
will be reduced.
> this secondary mmf will reduced to primary current. so it's
will create a large flux and the heating will also increase.
> and there is possibilities of shock to user so a C.T. would
never be open circuited.

Answer / ghanshyam singh

it ceases the back emf produced by the secondary of ct
this led to heavy inrush of current through primary as
there is no opposing emf
this may harm the person performing the experiment

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