Answer / rajesh verma

Dear
Please follow the Step
1 calculate your transformer maximum current with this simple formula
Transformer KVA X 1.39 A = will be the Maximum Tr ansformer Current
2 find out the Cable current Ratings chart from the Cable manufacturer data Sheet accordingly select cable but one thumb rule can help in this matter and it is Per Amp 2 MM SQ will be enough to carry out the current in any circumstances.IE Cable Length ,Cable Joint cable laying condition etc but remember you have to take care the welding load this will not by cover the thumb rule

Answer / h s sandhu

From the Equation P=root 3xVxIxP.F. we can calculate the rated current on the secondary side of the transformer. Knowing the value of rated current  we can select the cable size from the cable selection chart.

why we use tapechanger in primary side of transformer

5 Answers   Bhel, L&T,

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why we use ac?why we use dc? why we we cannot use only ac/dc for all the applications?what happen if we use?

0 Answers  

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how much current will be drawn by 3 phase, 415v, 50 hz, 20 ton central ac

3 Answers  

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Why the suply frequency in INDIA is 50HZ

2 Answers   HCL,

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what is the need to express current and voltage in rms value? rms value is also called as effective value,what is effective value?

0 Answers   Bhel,

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Why are use 22 kv 3ph supply ?

1 Answers   IOCL,

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What will happen if we give DC supply to AC motor?

9 Answers  

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what kvrah y we need to take the readind of that

0 Answers  

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On what basis the the size of Lightning arrester for buildings are selected ?

0 Answers   KGD,

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what do you mean by star point.its importance in ct & pt

2 Answers  

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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?

0 Answers  

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why rating of transformer is in kva instead of kw?

3 Answers  

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