Answer / nishad

See, Battery chargers are mainly useing for charging the
battery bank which is responsible for all control supply of
control systems such as breaker clossing coil, trip
coil,indications, protection relays, Annociators etc....
Mainly, If we are taking the supply from main, ( with
out battery back up)at the time of power failer /
breakdown how will record/ reccongnise the problem.
Secondly, Normaly we are using DC power for control.(
AC also using) for desired DC back up we can store the
supply in Battery. But inthe cause of AC how it
possible!!!!!
Moreover, in the cause control system, DC is more
efficient than AC

well, if any body can give another good answer, Most
welcome to Him. Because Knowledge is Power.....

Answer / komyozaw

Back up protection for power system.
Because when the main supply is failure and recover.
We do not know the recover voltage is Higher or lower than normal .So we should check and protect with protection relays.
this protection relays is power by battery charger.
Also all the system is shut down , the battery backup protection is remain.

Answer / trwer

See, Battery chargers are mainly useing for charging the
battery bank which is responsible for all control supply of
control systems such as breaker clossing coil, trip
coil,indications, protection relays, Annociators etc....
Mainly, If we are taking the supply from main, ( with
out battery back up)at the time of power failer /
breakdown how will record/ reccongnise the problem.
Secondly, Normaly we are using DC power for control.(
AC also using) for desired DC back up we can store the
supply in Battery. But inthe cause of AC how it
possible!!!!!
Moreover, in the cause control system, DC is more
efficient than AC

well, if any body can give another good answer, Most
welcome to Him. Because Knowledge is Power.....

Answer / sudhi.m.m.

i could partially agree with 1st and 2nd anrs, but having a doubt that cant we use relays, protecting system etc which works in ac, a substation will always maintain a supply by back feeding from other substation at the time of station shutdown, then why we are going for dc it self

Answer / kyu kyu win

1 ) to supply the stable Voltage output
2 ) to standby or backup protection .
Like mother look after her child
Mother = Battery Charger , Child = the whole control,
Metering and Backup
3 ) AC have frequency problem ( changes )
4 ) DC have not.

What is AVR in Turbo generator in Thermal power plant?

5 Answers   Thermax,

1)Why electric shock is feel ?? n in a Electric Train why we didnt feel that ? 2)What is the reason for transformer Noise ?? 3)What is relation b/w Transmission Lines & Communication Lines ? 4)Which material is used for making Transformer oil & How u measure its dielectric strength & Name the test ?

14 Answers   NTPC, Tata Power,

10Hp, 3-phase, 415v, 50Hz induction motor. The above motor is to run on Star-Delta connection, so how do i make following hardware selection 1) MCB, 2) Contactor, 3) Wire Gage (Depending on P-P current or Line Current), 4) OLR, Please tell in detail how to do the above, so as to get the ans. of it even if the Hp rating changes.

1 Answers   Engro,

Can we use Motor protection CB while we use the VFD for Speed control?? if not means please tell the reason!!!

1 Answers  

why the vector group of excitation transformer is YD5(150 deg)how is this factor decided.

1 Answers  

What is Isolation Current transformer and what purpose to use it in REF relay ?

1 Answers  

what is the purpose of the armored for the power Or control cable? How to select the type of the armored?

1 Answers   Siemens,

Dear Sir, I willing to know if one 15Hp induction motor run in star connection. What happen power capacity of motor? Plz tell me.

1 Answers   Amtek Tekfor Automotive,

How the electric train gets the supply of electricity? What is the return path of the current?

7 Answers   NTPC,

why use phase displacement in transformer.and effect of phase displacement on transformer

0 Answers   IOCL, ONGC,

new 90kw motor installed so how I purchased cable ,fuse,etc please give me technic for cable selected why always capacitor delta connection

0 Answers  

why the impedence of the transformer is expressed in percentage?

3 Answers   DEWA,