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Cram For The PE

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About Cram For The PE

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    Project Engineer

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    Power eng
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  1. First let me correct a common misconception. The three phase fault in MOST cases is the most severe. This is not always true. The SLG fault will be worse in cases where: 1-the generators have a solidly grounded neutral or low impedance neutral. 2-on the Y grounded side of a delta-wye grounded transformer. For practical purposes when solving these problems or when sizing your equipment, you can assume the three phase fault to be the worst. However, it is technically incorrect to say this is always true. Whenever your trying to size something for short circuit ratings, you ass
  2. Sorry for late response. But yes this was a typo on my part that has been fixed. The answer is in fact D.
  3. Send me email as detailed and you got it
  4. Chattaneer PE pointed out the problem with that solution. You can't solve the problem in the way you did. If your method was used correctly, you would have added the voltages as Chattaneer PE pointed out. It was really a combination of both his answers that made him correct. First, he recognized something was wrong with the MMF balance. Second, he wrote out the current and realized only zero would work to make the formulas correct. At that point, it was enough for him to get credit for the solution.
  5. I will give the first person to solve this problem a discount on my books. See Link for details. A three-phase un-grounded circuit with ABC rotation is connected to a resistive load as shown below. Ra, Rb and Rc are each 22.5 ohms. Voltage Vc Fails open. An AC volt meter is placed as shown below to determine the voltage. What will the voltmeter read? Answer to nearest tenth. You must show how you got the answer.
  6. You Sir have solved the problem. Which is good because I been waiting to post other problems and was sick of this one. Email me your information and tell me what you would like. MMF balance is impossible. The network draws no current and the input impedance is infinity (or the same as an open circuit). It is completely irrelevant what is connected on the secondary. As Mr Chattaneer PE has shown above, the only number that fits all of it is zero. Dennis Karst posted at my website and realized something was wrong. Chattaneer PE also realized something was wrong about MMF balance when he pos
  7. Send me email as detailed and its yours!
  8. Reward has been doubled. Solve it and get all my books for free or $100 cash.
  9. I am giving away my protective generator book as detailed here: First come first serve.
  10. I will give a hint. The answer is NOT 42! 😂. Narrows it down for you guys a little.
  11. You have to detail how you got the answer when you give one please.
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