Answer / rajesh

During faults (short-circuits), fault currents have two
components- AC component (Periodic) and DC Component
(Aperiodic). DC component will be decayed as per system X/R
ratio. circuit breakers are manufactured and tested to
break the fault current of specific AC component (Ib) and
DC component(Idc). Together can be called as Asymmetrical
breaking current.

Answer / vasu

DC component in circuit breaker is not related with trip
circuit system, it is related with making or breaking the
circuit at fault condition.

Answer / prathees

In a circuit breaker, always the trip circuit is DC. And it
is powerd by some battery back-ups or ups.
Because, even is the total power to the substation is gone
by some problems or faults, the trip circuit can be
operated without any problem as it is the safety for all.

Answer / ramesh.k

In circuit breakers having trip and close coils are purely
dc components, some CB's are having antipumping coils also
pure dc components and spring charge motor used as both ac
and dc.

Answer / deepak kumar

In CB basicaly on HVCB DC ckt is used for their protection
ckt (making/breakin) and indication ckt as well as for
auxilary ckt like antipumping/hunting ,PD,

Answer / murugavel

dc closing coil,spring chargingmotor,tripping coil, andi
pumpingcontactor

Answer / amit mathur

The closing coil and the tripping coil with dc to dc
convertor for appropriate operation.

Answer / arunmozhi

circuit breaker in closing coil and tripping coil worked
for DC voltage.spring charge only used for 220v AC voltage.

Answer / sunita

in circuit bkr. only closeing and triping coil is a DC
component spring chargeing motor is generally AC motor

Answer / nilkanth

In circuit brekar motor used for spring charging is DC
motor 110v DC.

Please let me know DG set b check how many hour and days.

2 Answers   Amazon, Cummins,

why there is a humming noise in transformer

6 Answers  

presently I am working in private sector.In powergrid interview recruiter asked me why you join this organization.

0 Answers   Power Grid,

why phase plates are used in transmission line????

1 Answers  

What are documents to be required for export of the material?

1 Answers   Siemens,

We know that, in case if there is a faulty insulation,or sc, the current is bypassed to earth through the earth wire that has low resistance.Actually, what will happen to that current that flows through gnd?In that case,if we come in contact with that faulty appliance, wont that current flow through us as we form a closed path by standing in gnd?Is grounding a safety measure?

3 Answers  

We have a 33/11kv switchyard having 12.5 MVA power transformer. We export & import power through this transformer. When we export power, the PF will be depend on GRID PF & when we import power the PF will be depend on our load PF. but the problem is that,when neither we export nor import but our 33KV vCB is in close position,our meter read the power factor 0.14 to 0.25 at that moment. So how can be we improve the power factor at that moment.

3 Answers  

why we use four type of phase angle difference between pimary & secondry winding of a transformer & where we use them?

0 Answers   Grasim,

Difference between field rheostat and armature rheostat.

0 Answers  

what is relay

8 Answers  

IS it possible for a feedbacksurge to travel over a wireless connection?

1 Answers   HP,

How to calculate the current carrying capacity of sized cables, and there is any formula. please send to 'than.achu@yahoo.com'

1 Answers   Blue Star,