Answer / nithi

when SEC of the CT open circuited,
1.high-voltage buil-up in the sec side
2.core saturation-over heat-result in fire(if
prolonged).
these things will not happen in ordinary
transformer.because,
PRIMARY CURRENT IS REFLECTION OF SECONDARY
CURRENT.SO,WHEN THERE IS NO CURRENT IN sec SIDE,ONLY NO-
LOAD CURRENT WILL FLOW IN PY WINDING.BUT IN CASE OF CT,PY
CURRENT IS INDEPENDENT.SO,IF SEC OPENED,NO DE-MAGNETISING
EFFECT &FORCED TO OVERFLUXING CONDITION.

Answer / pritam upadhyay nit p

when secondary is open there ic no flux due to secondary
current to oppose flux due to primary so due to high flux
there is very high voltage induced on secondary side which
causes sparking and damage of core due to high flux demsity.
in case of power transformer flux is constant whtheer
primary open or not so there is no such case as in ct..

Answer / bhatt

If secondary of CT is opened and as we know that primary
always flow the current and by transformaton action
secondary must flow the current but in our case secondary
is opened hence Extra high voltage is induced in terminals
of secondary which can be fatal.
In case of ordinary transformer if secondary is open
primary flows only no load current hence secondary voltage
is only rated secondary votage which is not as danger as in
the case of CT.

what is the definition of Nominal current or voltage

1 Answers  

---

break down of electricity is more in summer or in winter ? give reason

4 Answers  

---

why we are maintain phase to phase clearence

4 Answers  

---

Why cables and busbar both needed in LT Panels?

0 Answers  

---

why dc supply is not applied for step up or down in transformer

3 Answers  

---

why is  use the star and delta connection and difference

1 Answers  

---

in india why we not use frequency above 50 hz for distrubuting power ?

1 Answers  

---

Require Generator Capcity ( KVA ) for 3 Phase Motor having 4.7Kw with starting current of 16amps?

1 Answers  

---

Will The Rated Capacity of 20 MVA ,220/6.6 KV, ONAN cooling Power Tranformer be increased up to 25 MVA with respect to its %Impedence by ONAF cooling with same rating..?

2 Answers   Ambuja,

---

Can anyone send details regarding motor protection relays ? their manuals please ?

1 Answers  

---

1. Why a DC motor starter is called 3 point starter

21 Answers   ABB, CG, College School Exams Tests, Crompton Greaves, Infosys, Siva,

---

basic princple of induction and synchronous motor

1 Answers  

---