sir i am fresher.can you please tell me how can i get certificate of competency as electrical supervisor.

1 Answers   ONGC,

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is the secondary voltage of current transformer greater than primary voltage,,,,,,,,] give the example with ct burden,current ratio,and primary and secondary side voltage?

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Energy metering: On the property I am renting, the supply voltage is 2 x 110 volts. These 2 x phases enter a energy meter which then exit the meter to over head lines to my house. Question 1. The meter is single phase 240 volts but is being used as 2 x phase(2 x 110volt), is this acceptable? if not, please give me the reasons. The meter details are as follows: 60Hz 15amp Imax 100 amp Kd 3,6 Wh/R 1 fase 3 hilos Model FX 231. I think it was manufactured in Brasil From this meter, the cables run along over head aluminum conductors,I estimate the cross sectional area to be 25mm diameter, but the neutral is only about 10mm square diameter, which cover a distance of 170 meters and then terminate with an underground cable of 65 meter length, total length = 235 meters. There must be a huge voltage drop over this length. This line is protected with 2 x 200 amp aluminum fuses after the meter, there is no main switch in the distribution board. These 2 phases connect directly onto 2 busbars. Surely the neutral should be the same size as the conductors if not more? Question2. What are your thoughts about this installation, should there be better protection, is the neutral too small? During the night, the lights dim then brighten all the time, this cannot be good for my electrical appliances. In my home, I only have a small electric geyser and fridge, my stove works off gas. But when i use other appliances like the washing machine or microwave oven, the light dim. The internal wiring of this house is done with solid hard drawn copper wires and of course, they have to be under rated. I am a retired electrician by trade, but not on the metering and over head mains side, my experience is on the factory maintenance side of things. Your expertise on these matters will be greatly appreciated. Please inform me how to rectify or make any improvements Kind regards, my power bill is very expensive, so I need to know how to bring it lower. Kind regards, Brian

1 Answers  

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What is the difference between RCD & RCCB, Where it can be used

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hot water tank,top element 240v across,the bottom 120v across,why?

1 Answers  

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Which power will flow first if we switch on a motor? Active or Reactive? How?

5 Answers   NPTC,

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what is mean by descripiency relay? & wht is its ansi code?

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In siemens PLC, why do we want to move the data ?

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I have carried out wiring for lighting in a shed in Industrial area which contains Metal halide lamps & have balanced in 3ph.Now when we put all the lines on in the daytime the current taken at 3phases at MCB comes to be equal i.e.28,29,28Amps respectively but in the night time i.e between 7p.m.to 11p.m. at the same MCb the current is 52,59,62Amp, though I have fit 63A MCB it is tripping in the above period.What may be the reason.? Note: This industry is located in industrial area where majority of steel ingot manufacturing plants are there. Whether this may be due to harmonic? what should I do to overcome above problem.pl suggest urgently.

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1. What is differential relay? How it operates? 2.How to calculate the Short Circuit Impedance in Transformer? 3.What is the alternate solution for testing of polarity by using polarity tester while its milli ammeter does not works? 4. While testing the 33KV Busbar by using Hipot kit, what should be the test voltage we have to apply? 5. What is the procedure/activities to be taken to inject the current more than 2000A by using 2000A Loading Transformer? 6. Explain how you can give the overload setting to any Motor Protection Relay for a HT motors with formula and example? 7. Why restricted earth fault protection is needed? Why can’t differential Protection is sufficient? 8. What should be the minimum and maximum ohmic value for earthing? 9. Why DC Currents are not used in transformer? 10. What is the Frequency while we step up the voltage from 220V to 11KV? Is it possible? Explain it?

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what is a tri vector meter? what are the tri vectors?

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how to compute kAIC?  with formulas...

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