Answer / md. faruque

A combination of disconnect switches and breakers used to isolate equipment in substations. It refers to electrical equipment that regulates the flow of electricity within an electrical system. It is used by utility providers and private facilities alike for two reasons: to prevent overloads and short circuits, and to de-energize circuits for testing and maintenance. The most familiar types of switchgear are circuit breakers , fuses & lighting arrestors, which interrupt the flow of electricity to a circuit when its current becomes too high and directly pass the surge voltage to earth.
Main considerations in apparatus protection – transformer, generator and motor protection – protection of busbars. Transmission line protection – zones of protection.CTs and PTs and their applications in protection schemes.
Types of circuit breakers – air blast, air break, oil, SF6 and vacuum circuit breakers. Types of lighting arrestors are- horn gap, expulsion type, gapless metal oxide type etc. It is also classified on the basis of class.

Answer / k.prakashchandra

Switch gears include c.b.and isolators

Answer / younas

what is the important think in switchgear room

How many types of Differential protection are there? and what the special arrangement are made at the time of charging of a transformer on the Differential protection?

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what is meaning of Power factor?????????

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What will Happened if the polarity of CT is changed?

13 Answers  

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hello friends this is krunal here.. i have applied for he officer train in hpcl electrical stream.. any one who have applied before for electrical stream please help me out.. post ur reply to my mail id: krunal_airforce@yahoo.com.. any tips, old questions for paper or any help will do.. plz help me.. your faithfully, Krunal Darji

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Explain how you intend to work under pressure to meet up with deadline target?

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Sir, I need a power supply at 380V. The supply I get in three phase is rated 415V. The total supply I have from the supply company is 70KW. Kindly inform if it is better to use a voltage stabiliser for this purpose or a transformer

3 Answers  

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I am using submission of two ct in one and half scheme for 67/67N protection. Both CTs star point is grounded separately near ct box.Will two point ground give wrong tripping to 67/67N during fault or no matter.

0 Answers   NCC,

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how to check the earth resistance value& what is the minimum earth resistance for good earthing sysytem.

33 Answers   Brookfield, BSNL, DMRC, Epoch, KPTCL, Polycab, Power Control, SIEA, Siemens, Wipro,

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What is the difference between ground and neutral ?

2 Answers   TCS,

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At site, we have 30Kw motor (3 phase, 400V,50Hz) and FLC 54A as per the nameplate. At the time of starting it draws 840A instead of 390A (7.2%). As per the data sheet also its 390A starting current. it thru a dol starter from the MCC. can anyone tell what is the problem in the motor

5 Answers   ME,

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Why Batteries are rated as AH i.e AmpereHour,and its formula to converting AmpHour to Amp

4 Answers   Suzlon,

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1.what is the basic difference between surge arrestor and lightning arrestor and where we use it. 1.what is the difference between metal oxide without gapped lightning arrestor and with gapped lightning arrestor

2 Answers  

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