Answer / ccic

Cable/wire , i.e. the conductor should be rated for at
least 125% of the FLA. The upstream CB protecting this
conductor should also be rated similarly, i.e. for a load
with 100A as FLA, the cable should be able to carry at
least 125 A. The cable derating factors (type of cable,
type of installation, ambient condicions, Voltage Drop etc)
should then be used to select the ACTUAL cable. The CB
should be rated for 125 A (Instantaneous Trip setting)

Answer / k.p.sharma

Size depends on two things
1. Current rating normally load current should be 70-80% of
cable's minimum capacity.
2. Voltage drop should be within limit i.e. for lighting 3%
and for motor during starting within 10%.

1. name the relay for protecting transformer 2. Current Transformer 3. potential Transformer

1 Answers  

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actual rated capacity of a disc insulator??

5 Answers   OPTCL,

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Is motorized MCCB required rotatory handle

1 Answers  

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How much no load current of synchronous motor

0 Answers   Nirma, Sulphur Mills,

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Dear all, I just want to ask an expert on this forum for some insights. For the magnetic balance test, when applied voltage on a Delta-Star transformer e.g. Dyn11, the following relationships apply for HV side: 1.  H1-H2 = H2-H3 H3-H1 2.  H2-H3 = H3-H1 H1-H2 3.  H3-H1 = H1-H2 H2-H3 For the LV side also: 4.  X1-X0 = X2-X0 X3-X0 5.  X2-X0 = X3-X0 X1-X0 6.  X3-X0 = X1-X0 X2-X0 Is there a similar pattern for Y-d, Y-Y, D-d? And how about Y-z, D-z, Z-y transformers? I've tested a YNzn5 transformer and for LV side I don't see the pattern. In this particular case I got for LV side the following (see values below): H1-H0  H2-H0  H3-H0    X0-X1  X0-X2  X0-X3 128.0  119.9  7.2      29.2   13.3   15.8 70.7   128.4  59.2     23.4   22.0   3.6 7.2    120.1  128.1    13.4   29.3   15.8 What is the relationship here for LV? For row 1 I see the relationship, for row 3 I also see but it's shifted, but for row 2 I don't see such relationship. Any suggestions, answers, someone?

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in cvt,there are two windings,1a,1n and 2a,2n.in my one project i use only one winding i.e.1a,1n. the other winding is not in use, so i connect it in open delta and want to close it by ibsertibg thermal resistor. the output of cvt is 132kv/115/sqrt3. plesae tell me exact value of resistor, so i may close it to avoid the resonance phenomenin. send me answer on this email adress please. aetcon-po@aetcon.com

0 Answers  

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which part of transformer heats up the most and why? windings, core or oil .

3 Answers   Lafarge,

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tell me about roaster switch .& what is the function in transmission & distribution?

0 Answers  

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What is power in wattage of 8.5 TR AC

0 Answers  

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how to calculate power factor rating according to load? please give the answer in simple language, i'm not electrical side

2 Answers  

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which IS or IEC is used for earthing,breakdown voltage of transformer oil, hv/pd testing and all type of electrical testing

0 Answers  

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What is the effect on power factor, shown by a trivector meter; incase of reverse phase sequence. If the power factor of a system is lag what meter will show in case of reverse phase sequence connected to the meter. and What in case of lead.

0 Answers   TATA,

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