In a large office how do we calculate required number of light fittings, assuming fittings are 4x18W or 2x36W fluorescent fitting ?

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why corona ring is used in out door switchyard lightning arrestor

3 Answers  

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1)why the transformer rating in KVA insted of KW 2)why the secondary of ct is shorted and why the PT secondary is open

3 Answers  

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1.why are not using acb 33kv ht side? is there any problem 2.what is difference between acb,vcb,sf6 breackers? 3.what is the function of invertor and convertor in ups?

0 Answers   L&T,

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I have an existing old MCCB. ABB Model SACE, the rating are: Ue = 660 volts, Iu =1250 Amps, 3 poles, Ith (max) =800 amps at 45 deg C. I need a circuit breaker for my 3 phase motors, 380 volts 60 hz. the supplier required the minimum ampacity of the breaker to be 911 amps. can i use this breaker with rating of Iu =1250 amps but Ith = 800amps maximum?

0 Answers   Siemens,

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The sodium vapor lamp is not glows when it is connected a distance of 5 meters above from gearbox, why ?

0 Answers   Ispat,

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Why indicate only 440V to 3-phase supply.

4 Answers  

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total numbers of earthing of a transformer

1 Answers  

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how does capacitor oppose sudden chane in voltage? how does inductor oppose sudden change in current?

4 Answers   AAA, Iqra University,

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in 33KV or 66KV system which connection is aviable on high voltage transformer primary delta or star ?

3 Answers  

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plz tell me Motor IP formula

0 Answers  

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how could we findout the lightning arrester failed or not in live circuit? Is there any instrument to measure the high voltage at the time of sky lighting?

1 Answers  

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