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Is the Vrms to Vmax in HWR is (Vrms= Vmax/ sqr2 )or (Vrms= Vmax/2) I see in PPI book page 27-6 the second formal and on NCEES problem 515 the first formula. Thanks

Hi there, Question to the one who are expert in NEC! to calculate the size of overload protection device for motor, we use the currents listed on table 430-247 through 430-251 plus additional percentage of the currents depends on what type of motors we work with. What I don't understand is...

Hi there, I have a new delema, what is the equation for Reactive power with respect to voltage and reactance? There are two question in PPI power sample exams (P10, P12) which the Q is calculated and the book used (Q=(sqrt3)x(Vsquare/Xc). I think the formula should be Q= (Vsquare/Xc). Please...

Hello there, I don't understand problem 6 in volume 3 of Complex Imaginary. Why s = vI and not S = (sqr root of 3)xVxI? The book says because of delta and Y connection but we consider 3 phase system which it should be the same in delta and Y. I appreciate your comments. Thanks

Hi There, Does anyone know the answer for question below? two transformers are connected in parallel. both have delta primary and wye as secondary. That means delta connected to delta and wye is connected to wye. Is this connection okay or it will cause circulating current? I appreciate...

Hello there, Can any one tell me what happens if in 4 wire three phase wye connection, one of the phase completely get diconnected? Thanks

Hi there, Does anyone enrolled in MGI PE Review Course? It is from Smart Pros. The website is http://pereviewcourse.com/. Please let me know what you think if you had the course before. Thank you

Can someone explain the solution for problem below? Design a full wave rectifier power supply that has an input of 120 Vrms, 60 HZ and required a max voltage output of 17 V and a min. output of 12V. the power supply will provide power to an electronic circuit that requires a constant current...

Hi there, Hope you, smart engineers, do not get tired of my quetions. I am planning to pass the exam this time and I do not want to leave any doubt behind me. I am hoping that my quetions not only will help me to understand the material better, It also help the others by discussing the...

Hi there, I got stock with another problem. I can not get the right answer and it is frustrating me. I know there are lots of smart ones out there. Please help. Thanks A three phase, three wire, 500V, 60HZ source supplies a three phase induction motor, a wye connected capacitor bank that...

Hi there, I am studying Schaum's power book. Some of the problems only have the final answer. Hope you guys don't mind answering my questions. Here is a new one A three phase balanced load has a 10-ohm resistance in each of its phases. The load is supplied by a 220 v, three phase source...

Hi there, I can not get the right answer for the problem below. any help will be appriciated. A single phase transmission line supplies a reactive load at a lagging power factor. The load draws 1.2 pu current at 0.6 voltage while drawing 0.5 pu (true) power. If the base voltage is 20 kv and...

Hi, I am trying to solve the problem 6, Vol 2 of the imaginary book. I blieve the answer is wrong. Here is the question. Hope some one give me the right answer: A delta-wye transformer is rated for: 34.5kv/480v, 125 A primary current (L-L). What is the transformer's power rating (KVA) and...

Hi there, I am taking power exam in october and would like to find a study partner or if lucky have study group. I live in Fresno ca. I think it helps a lot studying as a group. Thanks