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Many of us have been working with various practice exams to prep up. I highly recommend you check up on Zach Stone's Electrical PE Review website. Just Google Electrical PE Review, should be pretty easy to find. He also has put up some of his explanation videos on YouTube. Since I understand...

I can't really answer for 6, but I will answer for 3. Yes, the integration from theta 1 to theta 2 is unique/exclusive to IGBTs. They have both a firing angle for starting conducting and a firing angle for stopping conducting. It's a step up for controlling firing, from SCRs which only control...

You can still (and you are supposed to) use Z pu new = Z pu old * (S base new/S base old) * (Vbase old/V base new)^2. You just need to make sure you are using the correct base voltage value, keeping in mind that each transformer changes the base voltage value between different zones.

The problem statement specifically stated to use another voltage value as the voltage base - the 69 KV voltage as the base on the distribution zone, then converted through the two transformers' turn ratios to get the 15 KV base voltage at the generator that you're supposed to use for the...

Also I think I should mention the rules for setting a system base. When you are given a base power (VA) value to use, this base power applies to the entire system (regardless of transformers in the system). When you are given a base voltage value and there are transformers in the system, the...

I have it in front of me and am looking at 32. The question states that the system voltage base at the distribution bus (all the way downstream) is equal to the secondary voltage rating of transformer T2, the most downstream transformer. So then you have to work upstream converting the...

I have the exam, though it is an earlier version. The author of the exam also visits and peruses this board. I confirmed with him that there are no major changes between the early version I have, and the latest version. Which specific questions are you having trouble with on the Electrical PE...

Hm, so here what about the valued between 1.25 and 1.4? Do these values count as only good insulation?

Hey guys, I have a silly question about dielectric absorption ratio. Many times I have seen that the standard dielectric absorption ratio R 60 sec / R 30 sec judges insulation condition as follows: DAR < 1: Bad or dangerous insulation 1 =< DAR < 1.25: Questionable insulation 1.25...

Thanks for responding, Cram! So I guess in the original question, the 30 Hz transformer with the 60 Hz voltage doesn't saturate then (its Vrated/frated ratio is low because f actual > f rated). The 30 Hz transformer would experience an under-flux instead...

Hm, not sure about that. I have the Cram for Exam volumes, so I am familiar with this question. I don't believe the question stated that the transformer is designed at a different voltage from the generator or motor. So based on that, I think the transformer's rated voltage is safely assumed to...

Hey guys, Does anyone know if synchronous generators have V curves like synchronous motors do? I came across V curves for synchronous motors while doing the Shorebrook PE Power practice exam, and the Wildi book also briefly touches on V curves for synchronous motors... but I don't remember it...

I think the issue that PEExam123 is confused about is why the transformer's core would saturate when the transformer is rated/designed for 30 Hz.... Which I can't really explain either. DarkLegion is correct that normally saturation will occur when the V/f ratio is too high (either the voltage...

That is VERY enlightening! I wish I thought of that. Thank you, @Cram For The PE!

So then, does that mean for the case of a grounded Y feeding a corner-grounded delta, the corner-grounded delta's phase voltages are Vab = Vbc = Vca = 7.62 KV? (Magnitudes only) So then does that mean that for a grounded Y feeding a corner-grounded delta, the corner-grounded delta's delta phase...

Hey guys, Quick question about ideal excitation of a synchronous machine. Normally a synchronous machine is ideally excited when Re(Ea) = |Vt| (the real component of the internal or induced voltage phasor equals the magnitude of the terminal voltage phasor). What percentage tolerance (e.g...

I took some time to draw out the transformer phase diagrams, both for just 1 phase and for the 3-phase transformer as a whole. Hope this helps.

Attached is how I broke down this 3-phase transformer into the individual phases on both sides of the transformers. I have one more illustration coming up, give me a few more minutes.

When you use the single-phase or per-phase turns ratio (a 1-ph), that is the ratio of the secondary phase (wye or line) current to the primary phase (delta) current. When you use the overall 3-phase turns ratio of the 3-phase transformer as a whole (a 3-ph), it is the ratio of the secondary...

This is very helpful. It's why when I study and do conceptual qualitative questions, in addition to choosing the right answer, I also write down why the other wrong answers are incorrect. It helps me better drill conceptual items into my memory.