What_is_mean_by_negative_dc_voltage? why we use -48v except +48v in DC power supply systems.

2 Answers   APEL, BSES,

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what is joule?

2 Answers  

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what will happen if we use earthing inplace of neutral for domestic energy meter

5 Answers   Polyplex Corporation Limited,

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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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hi friends iam collecting details about motor,generator & transformer so send some web links to about motor,generator & transformer ,please help me .i need your help.thank u

4 Answers  

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What is mean by powerfactor. What is the difference between leading and lagging power factor?

2 Answers   HCL,

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How do you select a cable size(Cu&Al) for a particular load

10 Answers   Adhunik, BPCL Bharat Petroleum, Hiecon, TATA,

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What is RTCC in a transfomer and specify its function.

11 Answers   MCB, Vodafone,

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A 7 storey building has a floor area of 35,000sq.ft on each storey. On the ground floor 11KV electrical sub-station is to be erected. A load of 3kw for every 400sq.ft (p.f is 0.8) is proposed for each floor. fire pump 7.5hp, water pump 5hp, lift 2 nos, each 10hp and 20shop load of each shop is 5kw. calculate a. load each floor b. total load of building c. L.T feeders for aech floor and from transformer to main. d. distribution diagram e. capacity of sub-station/capacitor bank f. line diagram

0 Answers  

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upto how much low RPM we will run the commercial motor which is run through VFD without any problem occurs in motor.Motor rating Duty is S1 & RPM is 1400.

0 Answers   ABC,

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What is Grounding? any difference b\w earthing? if yes plz explan??

3 Answers   ABB,

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Is there any problem ,if R-Y-B voltage is constant , but the air compressor taking one phase high current.what is possible causes.the said compressor is very new.(55kw).

4 Answers  

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