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### Help Support Professional Engineer & PE Exam Forum:

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1. ### Passed the Power PE Exam on my first try!!

That is not correct. All codebooks will be provided. You will be able to use the search function as well. And you don't need to memorize codes, but you need to know where to look at. For example, if the question asks what the width of the working space in front of the electrical equipment is...
2. ### CA Power PE License Application Timeline

Someone I know said it took them about six months. This was about 8-10 months ago. Not sure if it is better now.
3. ### Transformer Question

@Zach Stone P.E. explains this in his class. I am not sure if that particular video is available for free. Don't take it the wrong way but looking at your posts, it seems like you are struggling with the basics. If you want to pass the exam, you need to know the basics. I highly recommend you to...
4. ### Study Guide For PE 4.1

That's because the power loss is given in Watts, which is the real power loss. Real power loss per phase= I^2*R. Power Loss per phase= 100W. R is given. So, 100=(I^2)*3, which gives I= 5.77A. Here phase current=line current.
5. ### Current Transformer Question

Looks like it comes from IEEE C57.13 permissible error. Here, the graph shows 0.6% accuracy region for currents less than 100% for 0.3Bxx CT with 4.0 rating factor. "The limit of permissible error in a current transformer accuracy class has one value at 100% rated current and allows twice that...
6. ### PE Power materials

You can't go wrong with one of these: 1. Electrical PE Review 2. Engineering Pro Guides
7. ### I need PE Power materials

I have some materials I am looking to sell.
8. ### 50 Minute Break

80 questions are divided into two sections. Usually it's not 40-40, rather 41-39 or 42-38. The 8-hour timer will start once you go to the first question. Once you finish the first 41 questions, you will have the option to take a scheduled 50-minute break. Once you submit the first section, you...
9. ### Clarification for NCEES Question for Line to Line voltage when voltage across load is provided

When you solve these kind of circuits, always draw the per phase equivalent circuit. The impedance of line are also per phase values. So, you calculate the phase values and change it to line values. If the load is in delta, convert it into Y. For balanced load, Z_Y=Z_delta/3
10. ### Transformer Losses Clarification for NCEES #524

Copper loss at full load is Pfl= (I_fl)^2*R At 50% load, I_50= 0.5* I_fl This gives P50= (I_50)^2*R= (0.5*I_fl)^2*R= 0.25 *(I_fl)^2*R= 0.25*Pfl So, P50= 0.25*Pfl. And Pfl= P50/0.25= 4*P50
11. ### Auto Transformer NCEES #535 Solution Clarification

Interesting. If we use Zach's equation, Sc=Sse= 16.5 MVA. This gives Srated= Sc+Sse= 16.5+16.5= 33MVA. They should add up to 60MVA, no? Srated is 60 MVA. I am not sure if I am missing something. Maybe @Zach Stone P.E. would like to chime in.
12. ### Auto Transformer NCEES #535 Solution Clarification

For step up auto transformer, Scond=V1*I2 and Sind= V1*Ic
13. ### Auto Transformer NCEES #535 Solution Clarification

1. Correct 2. Correct 3. Sc= V2*Ic, Sseries= V2*I1 or you if you have Sc, Sseries= Srated-Sc= 60MVA-16.5MVA= 43.5 MVA Srated= V1*I1 or V2*I2
14. ### Help with Pu conversion for sample PE 3-Phase Fault question

Do not use that equation to calculate the pu value. That is the actual value of short circuit current. I_base= VA_base/sqrt(3)*V_base and Isc_actual= Isc_pu*I_base Use this equation to find the impedance, S=V^2/Z, so Z=V^2/S. To make it easier to memorize, remember the Ohm's law (V=IR)...
15. ### Auto Transformer NCEES #535 Solution Clarification

Autotransformers are different from a two-winding transformer. In a two-winding transformer, power is transferred inductively. But, in an autotransformer, power is transferred both inductively (at common winding) and conductively (series winding). There is no electrical isolation between primary...
16. ### Help with Pu conversion for sample PE 3-Phase Fault question

See this: NCEES Problem #70
17. ### Help With Per-Unit Impedance Base conversion

Select transformer's primary as base kV. Now the Vpu of source will not be 1, it will be Vpu=Actual Voltage/Base Voltage=20kV/22kV=0.9 pu Calculate the impedance up to fault point only. If the fault is at VT, you do not need to calculate the impedance beyond that fault point.