can some one clearly explain why -48 volt DC use in telecom site????

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Why screen of the screened cable not earthed on both the ends of cable

1 Answers  

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what is the formula to calculate kva genset required for a given load in kw.

3 Answers  

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How much is the starting current for HPMV lamps. How many lamps can u wire in a circuit

1 Answers   Technip,

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HOW TO IDENTIFY THE RELAYS WHICH APPLICATION IN WHICH RELAY USING

3 Answers  

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What is the function of a turbo charger in a 1000kva DG set

6 Answers  

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what is relay

8 Answers  

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is dc transformer is possible ?

4 Answers   Jyona Power,

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what ll happen to current if two phases get short circuited

2 Answers   Kirloskar,

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I am looking for LV CT test. To check the polarity of the CT only. Can you suggest any supplier. Different companies are offering CT/PT Tester which is expensive. Thanks

2 Answers  

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When we use air circuit breaker, it has O/L protection ,time delay SC protection, Instataneous SC protection & ground fault protection. They all have some setting range. But what is the suitable/allowable setting for the above protection which will be safe for the equipment? For example-O/L protection setting have a range of (0.4,0.45,0.5,0.55,0.6,0.65,0.7,0.8,0.9,1.0)xIn Time delay SC protection have a range of (1.25,1.5,2,3,4,6,8,10,12)xIn Time delay setting is 0.02,0.1,0.2,0.3,0.4 Instataneous setting is fixed to 20xIn Gound fault setting is given 100A,300A,600A,900A,1200A This setting are for 2500A ACB. So what will be the basic allowable setting for the above protection? is there any formulae to calculate this<

0 Answers   Lupin,

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what s a servo motor? how to control the servo motor? and its application, purpose of using?

2 Answers   Arabian Pipes,

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