# Recent content by Zach Stone P.E.

1. ### Passed PE Power Exam

Congrats on passing the PE exam @no_concentrate !!! Thanks for being a member of our online class for the new CBT format of the Power PE Exam 🎉
2. ### Power PE- Transformer impedance referred to Pri and Secondary

If I am understanding your question correctly, then the answer is because when we use percent impedance (Z%) to calculate the impedance of the transformer on either the primary or secondary side, the resulting impedance value is the total referred impedance which is the sum of the impedance...
3. ### Power PE- Transformer impedance referred to Pri and Secondary

Hi @CeeYem, The change of base formula for the per-unit system is not used here. The referred impedance formulas are derived from the transformer ratio formula and Ohm's law. Here is a quick sketch off the top of my head to help demonstrate:
4. ### Jacob PASSED the Electrical Power CBT PE Exam (after two failed attempts!) July 2021

Many of you have been asking for an interview with an engineer that had to take the PE exam more than once so you can learn exactly what they did differently in order to pass. This week I had the opportunity to speak with Jacob about how he did just that after two previous failed attempts...
5. ### Power PE 61

The instantaneous overcurrent trip function typically operates with a time setting (or cycle setting) of zero. In other words, the current is so great, that the relay should trip the OCPD immediately without a time delay.
6. ### Planning on taking CBT, studying advice

Hi @mnsee glad to see our practice exam in your list! If you're looking for advice and personal experience from other power engineers that have passed the new CBT format of the Power PE exam this year, take a look at the following youtube playlist: Youtube - "How to Pass the CBT PE Exam"...
7. ### PE Electrical Power Reference Handbook 1.1.2 Effective beginning October 1 2021

Luckily nothing major. Mostly minor corrections, the addition of titles where they were missing, and a few variables that were re-labeled. No one panic! It's the same reference handbook :D
8. ### How to Solve Transformer Open and Short Circuit Test for the CBT Electrical Power PE Exam (Electrical PE Review)

Transformer Open and Short Circuit Test - Example Problem: Tonight is Live Class #3 - Transformers for the new CBT format of the Electrical Power PE Exam. To help you solve transformer open and short circuit test problems, here is a new 30 minute YouTube video from last semester's...
9. ### How to Solve Transformer Open and Short Circuit Test for the CBT Electrical Power PE Exam (Electrical PE Review)

Transformer Open and Short Circuit Test - Example Problem: Tonight is Live Class #3 - Transformers for the new CBT format of the Electrical Power PE Exam. To help you solve transformer open and short circuit test problems, here is a new 30 minute YouTube video from last semester's...
10. ### July Exam Takers

Congrats @jsk020 !
11. ### Selling Electrical Power PE Study Materials

Hi @CynicalTechHumor, happy to see our practice exam on your list. How did it compare to the others that you used, and did it help you prepare for the PE exam? Bummer about the ikea table :)
12. ### NCEES #136

The power factor comes out to zero only when the load is either 100% capacitive (-jX = -90º) or 100% inductive (+jX = +90º). Ex: PF = cos(ø) PF = cos(90º) or cos(-90º) PF = 0 You can tell if it is lagging or leading by the impedance. Capacitive loads have a negative j in front of the...
13. ### NCEES Question #510

The 1.15 FLC multiplier comes from NEC® 430.32(A)(1) Continuous-Duty Motors Separate Overload Device.
14. ### July Exam Takers

Thanks for the mention @patkt! Congrats again on passing the PE exam. Thanks for the mention @jsk020! Please email me when your results come in so I can follow up with you. Good luck!
15. ### How to Solve DC Circuits for the CBT Electrical Power PE Exam

Live Class #2 - Circuit Analysis for the Fall 2021 Semester starts TONIGHT at: Tuesday, July 13th, 20213 PM (PT), 4PM (MT), 5PM (CT), 6PM (ET) Will you be joining us? Click the thumbnail in the below to watch a short clip of last semester's circuit analysis live class and learn how to solve...