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Why the voltage drop formula to solve these two problem using the "subtract": V(d) = I * {R*cos(theta) - X* sine(theta)} * L/1000 From table 9, NEC book. It is shown as ( + ). Can some one explain to me please?? Thanks,

Wildsoldier, Can I email you for some question regard to exam materials? Or please email me at: [email protected] Just so frustrated since the more I study the worst score I got??? Follow the advised from the board and took the GA Tech course after 2 times failed. Just don't know what am I...

On P-47b & P-47c Sample problem. V(ab) = -V(ba) = 200 angle -30 degree V(bc) = -V(cb) = 200 angle 90 degree V(ca) = -V(ac) = 200 angle 210 degree I used calculator to get the answer from V1, V2, V3 by convert -200 angle 150 degree to rectangler and then convert it back to polar to get...

Is anyone taking the course for the October exam? Any of you check the sample Economic problems? There are 4-5 answers are not correct. Problem 3, 5, 6 & 11. I don't know if I don't get the answer correctly or because it is wrong?? Please let me know if your answer is the same with the...

If we have a 3 phase AC, unbalance system (or delta-Y system or Y-delta), how many PT & CT do we need to measure the load? Should it be (3) CT & (3) PT?? If there is a neutual in the system, do we need (1) more CT & (1) more PT? In the text book didn't say much about this topic...

Master DK, I need your help about this please! Here is the problem A three phase, delta-wye connected, 15KVA, 33/11KV transformer is protected by CTs. Determine the CT ratios for differential protection such that the circulating current (through the transformer delta) does not exceed 5A...

Hello, I am a new member. I have a question about the autotransformer ratio. When should we use the formula: V1/V2 = N1/(N1+N2) and: V1/V2 = N1/N2 Here is the problem: 1. In a edeal step-up autotransformer. Give N1= 200 and N2=400. If 100V is applied across the primary, what is the...