Question { Bhel, 17476 }

it is clear that volts equal to the current as per ohms law.
is it appliable to the AC power or only for DC. if it is
appliacable to AC in transformers when voltage increases
the voltage decreases ????? why??????????????

Answer

ohm law is applicable for both ac and dc
according to ohm law if we pass current through any
resistive ckt, the ratio of change in current directly
proportional to change in voltage
V = I*R (where R is constant)
but in case of inductive ckt (like transformer), inductance
of the ckt always try to oppose the change in current, but
in case of dc inductance of the ckt is zero, so in case of
AC, voltage vary nonlinerly with change in current.
(remember ohm law in not applicable for inductive ckt it is
only applicable for resistive ckt)

Question { Neco, 28300 }

WHAT HAPPEN WHEN CT SECONDARY OPEN DURING LOAD

Answer

CT means current transformer which help us to measure the
large amount of current by step down the value of current
to low value. CT primary wdg handle the large amount of
current due to which large amount of heat is produce at
primary winding so we use insulating oil which help to
provide insulation as well as provide cooling. If we open
its secondary winding, the secondary current will reduce to
zero, which cause increase in voltage across its secondary
open terminal and that leads to increase in primary
current, with increase in primary current temperature of
oil in CT also increase and oil start burn which leads to
blast in CT