Don't get discouraged. I passed the EIT the first time through, but it took me multiple times to pass the PE. Failing was due to multiple issues. I'm 53, and I have been working in manufacturing since I graduated back in the 90's. Since I do not do electrical design work, I'm behind the eight ball compared to EEs designing electrical systems. Taking the power exam required me to self teach myself most all of the topics covered on the power exam. However, I did pass this past April, and I wanted to share my tips on what I did to pass.
I would suggest taking a review course. Review course comments - I took Georgia Tech's PE review course, and I thought it to be better resource than the School of PE. The provided study notes and suggested textbooks were extremely helpful. My colleague took the School of PE and passed it the first time. He just had taken the EIT, and he was pretty fresh. He lent me his study material, and in comparison, I believe the Georgia Tech prepared me to answer the majority of questions on the exam, and Dr. Callen is very helpful and quickly responds to your questions. The school of PE strength's are in the outlier topics that they cover like batteries, hipot testing, etc.. Keep in mind, outlier questions are equally weighted compared to standard NEC questions like those covering voltage drop. Again, my colleague passed the first time after taking the School of PE, but I believe it had to do more to being fresh taking the EIT. I'm sure other review courses, like Zach Stone's, are just as helpful.
One of the text books Dr. Callen recommended to purchase is titled, “Electric Machines and Power Systems” by Vincent Del Toro. I used this book to learn more about transformers and motors. In fact, Chapter 4, Section 4-12 titled, "CONTROLLERS FOR THREE-PHASE INDUCTION MOTORS" contains a reduced-voltage magnetic controller line circuit, Fig 4-38, that I used to help me answer an almost identical line circuit that was on the exam.
One textbook recommended on "engineerboards" that I found to be very useful is titled, "Electromechnical Energy Devices and Power Systems" By Zia Yamayee and Juan Bala. This book was an excellent complement to your review course. I was able to find the solutions manual online for chapters 2-8. The solutions manual really helped by including solutions for the drill problems and the end of chapter problems. I completed all the drill problems for chapters 2-8, and most of the end of the chapter questions. In addition, I reviewed chapters 9 and 10 as well, which was able to help me answer some relay and transmission line questions.
There are a number of VFD questions on the exam, and I printed Siemens Step 2000 training module titled, "Basics of AC Drives," which helped me answer some VFD questions. I found that a lot of review material from School of PE, Georgia Tech, and others do not cover VFD questions, which in my opinion is a big oversight. However, I believe the Georgia Tech course is going include VFDs. You can download the pdf by visiting the Siemens link http://www.sitrain-lms.com/step.aspx?fromLogin=true
Reviewing Youtube, MIT, and other online videos for topics to help me uderstand the topics.
I would suggest taking time off. Take the review course, and get the highlighted books and solutions manual and start going over the questions. I made copies of the questions, and was extra neat with my answers to ensure that the answers would be a good resource to take into the exam.
Don't give up!