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Voltage Levels
Why all voltage level are multiples of 11, like 220V, 440V, 1100V instead of 200V, 400V, 1000V?
pradipsabar2009
- Jul 30th, 2010
The value of form factor is 1.1 which is calculated for the sine wave. At this value of form factor, leakage flux is minimum and efficiency is maximum for any electrical machines. These machines are operated at sine waves.
dhrumil041189
- Jun 11th, 2010
Because number of disc of insulators are rated in order of 11 kV so all these are transmitted in the multiple of 11.
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Fault Detection in Underground Cables
If there are three underground cables if a fault takes place in one of them, How will you detect it?
pradipsabar2009
- Jul 28th, 2010
Measure the resistance of each cable between farther ends, if there is a considerable variation in any one of the cable, that is the faulty one. This method is also used in industries called as "Insulation Resistance Test".
dhands
- Jun 6th, 2010
1. Check phase to pase insulation resistance value and phase to earth insulation resistance value.
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Power Lines Protection
Why the 1st zone of protection relay is 90% not 100%?
ashokumarrk
- Nov 14th, 2010
Zone-1 protection is 80% in (NTPC, POWER GRID, NPCIL, NHPC, BBMB....) bcz we have consider the errors in CT, PT and also the line length. Datas provided should be same as the actual, but it wont. In order to compensate all these Zone-1 protection is 80%
pradipsabar2009
- Jul 29th, 2010
If we consider the 100%, 100% in the sense there is another CB present there. so there is a dilemma which CB should operate first. Hence the first zone of protection is never 100%
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Power Between Source and Load
When eletricity is not used what happens to power between source and load?
pradipsabar2009
- Jul 30th, 2010
The power generated by source quickly responds to the load. If the load is suddenly disconnected, there will be only line load present so source cannot quickly change itself as a result heavy transien...
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Electrical Engineer Interview
1. what is the different between CGS system and MKS system? 2. When we connect the capacitor Banks in Series with the circuit 3. What is the difference between Earthing & grounding 4. how much voltage is present in neutral resistance?and how much voltage is present in earth resistance... 5. What is the purpose of calculating knee point voltage for Current transformers? 6. What is the voltage drop for...
SURAJTHEGREAT
- Apr 10th, 2011
When capacitor is connected in series with the supply source (dc battery) ,capacitor gets fully charged and as a no current flows to the load!!!! When capacitor is connected in series with the supply source (ac) ,a leading current flows through the load.
