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Professional Engineer & PE Exam Forum

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  1. Zach Stone P.E.

    PE- Electrical/Computer engineering

    Thanks for the mention @main197 !
  2. Zach Stone P.E.

    In case you missed it: Last night's free live class recording - New AIT Practice Exam Book Launch and Solving 3 AIT Practice Problems

    In case you missed it, here is the recording of yesterday's free live class for our new AIT only practice exam book launch. Last night I solved three AIT Practice Problems from our brand new book Electrical Power PE Practice Exam: 80 AIT Practice Problems for the CBT Format. You can watch the...
  3. Zach Stone P.E.

    I finally Passed the POWER PE

    Congrats again! Thanks for being a student in our online class for the new CBT format of the Power PE Exam at Now enjoy the celebration!
  4. Zach Stone P.E.

    2 Wattmeter Method Question

    Hi Rafis, There is a lot of great information on these boards already for the two-wattmeter method. If you use the search bar you'll be able to dig up plenty of prior threads that can help you with this. In the meantime, here are my three favorite videos that I made to help engineers with the...
  5. Zach Stone P.E.

    PE Power Exam Results (failed)

    Thanks for the mention @DLD PE !
  6. Zach Stone P.E.

    Relay Questions

    At the very least be very familiar with the ANSI numbers included in the Reference Handbook, but a general understanding of relay principles, applications, and theory is reccommended.
  7. Zach Stone P.E.

    Auto Transformer NCEES #535 Solution Clarification

    Yep! Turns ratio is a = N1/N2. For a step up autotransformer, N1 = Nc and N2 = Nse + Nc. For a step down autotransformer, N1 = Nse + Nc and N2 = Nc. See the video above at 21:30 for an explanation of both.
  8. Zach Stone P.E.

    Auto Transformer NCEES #535 Solution Clarification

    Determining the rated power of an auto-transformer It's just about as straightforward as determining the rated power of a regular transformer. The same formula applies: |Sin| = |Sout| |V1|·|I1| = |V2|·|I2| It's just the product of the primary voltage and current or the product of the...
  9. Zach Stone P.E.

    PE Power 522 pf

    Hi @Mr-T_Swift, Here is a quick article you'll like to help you remember the difference between the power angle and the current angle (and how not to mix them up): Leading and Lagging Cheat Sheet! Printable Reference
  10. Zach Stone P.E.

    Power PE 61

    Sure. If you are referring to time delay overcurrent protection (ANSI #51) as opposed to instantaneous overcurrent protection (ANSI #50), the TCC (time-current curve) for the relay or overcurrent protection device will tell you how much time typically in seconds (as opposed to cycles) that the...
  11. Zach Stone P.E.

    Auto Transformer NCEES #535 Solution Clarification

    Thanks for sharing this video. There is an updated version of this video that uses the same variables used in the Reference Handbook for added clarity:
  12. Zach Stone P.E.

    Auto Transformer NCEES #535 Solution Clarification

    Unfortunately, summing the series and common winding power does not add up to the power rating of the auto-transformer. However, you can use the series or common winding power along with the turns ratio of the auto-transformer to calculate the power rating of the auto-transformer using the...
  13. Zach Stone P.E.

    Help With Per-Unit Impedance Base conversion

    Thanks for sharing my our per unit explanation article for the PE exam, @main197!
  14. Zach Stone P.E.

    Electric Machinery and Power System Fundamentals (Chapman) Problem 7-7

    That is interesting. I'm assuming that by Pmech, Chapman is referring to the mechanical losses from friction, windage, and stray losses, or: Pmech = Pf+w + Pmisc If Chapman is calculating the output power (Pout) from the converted power (Pconverted), then yes I agree the core losses (Pcore)...
  15. Zach Stone P.E.

    Electric Machinery and Power System Fundamentals (Chapman) Problem 7-7

    Hi @the_r0b, you raise an interesting question. I find two things interesting about this. 1. The difference in the air gap power (PAG) calculated using the book's method, vs calculated using P_AG = P_in - P_SCL - Pcore is the same value as given core losses of P_core = 200W. 2. Although the...
  16. Zach Stone P.E.

    ⚡️ Wave Propagation and Electrodynamics [Electrical and Computer FE Exam]

    Here is an example video on how to solve wave propagation for anyone that needs help with learning electrodynamics for the Electrical and Computer FE Exam:
  17. Zach Stone P.E.

    AutoTransformer Question

    Three 25 kVA single-phase transformers connected together to serve a three-phase load will be able to supply a total of 75 KVA. Each individual transformer is supplying 25 kVA.
  18. Zach Stone P.E.

    4th time the charm

    Thanks @COJeff !
  19. Zach Stone P.E.

    Electrical and Computer: Power P.E. Exam Study Question

    Thanks for the mention @akyip! @jkattan if you haven't already, I suggest taking a look at the Power PE study videos we have on your YouTube Channel and the free online course work we have included in the Free Trial of our online program for the Power PE Exam to get you started on the right...
  20. Zach Stone P.E.

    4th time the charm

    Congrats @Tokoyoshi! Thanks for being a student in our online class for the new CBT format of Power PE Exam at Always happy to hear when we are able to help engineers with a different engineering background like mechanical pass the power PE exam.