why a pilot exciter is used in combination with the main exciter? why not only a main exciter is used for excitation to an alternator?

1 Answers   Electrical,

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I am using submission of two ct in one and half scheme for 67/67N protection. Both CTs star point is grounded separately near ct box.Will two point ground give wrong tripping to 67/67N during fault or no matter.

0 Answers   NCC,

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In case of HV test on medium voltage cables, BS is asking for 4 U0 where as IEC is asking for 3.5 U0. Can any one advise me how this 3.5 times or 4 times U0 is derived?

0 Answers  

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List the power rating of any 5 important electrical appliances used in houses.

0 Answers  

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why bucholtz relay placed inclined in transformer?

1 Answers  

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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?

0 Answers  

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1.what is meaing of ups,and used in softwares and sud stations,and main partes in ups. 2.main partes of the Disel Genarator. 3.main partes of the chiller and safty equipments.

2 Answers  

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how to calculate neutrel current

2 Answers  

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What is meant by positive and negative feedback?

0 Answers  

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why the amount of voltage generated at power generating stations is 11 KV only....?

3 Answers  

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what factors to needed while selecting a MCB and MCCB

3 Answers  

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what is current

53 Answers   Bio Enterprises, CLG, TCS,

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