# Kaplan 134



## jdd18vm (Oct 7, 2007)

Can someone explain why their formula page 73, for VR=Vfl-Vnl/Vnl, is opposite the EERM 40.11 which is Vnl-Vfl/Vfl?

john


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## Dark Knight (Oct 7, 2007)

jdd18vm said:


> Can someone explain why their formula page 73, for VR=Vfl-Vnl/Vnl, is opposite the EERM 40.11 which is Vnl-Vfl/Vfl?
> john


I think is an author's preference thing John. Either way it should be the same result, I think.

For what it might work, I used the formula from a Machine's book I have and did stick with that one all the time. That formula is the one EERM uses.

The other one is also OK so you use the one you feel better using my friend.

You are doing great. Keep it up for a couple of additional weeks and you will get a very nice Christmas gift!!!!!


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## benbo (Oct 7, 2007)

I can't find this book - I must have given it away. It is probably a typo. THere may be some circumstances where these are equal, or the Kaplan formula is correct, but I would go with the formula from the EERM to be safe.


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## Dark Knight (Oct 7, 2007)

benbo said:


> I can't find this book - I must have given it away. It is probably a typo. THere may be some circumstances where these are equal, or the Kaplan formula is correct, but I would go with the formula from the EERM to be safe.


They used the absolute value on Kaplan's. They change the order in the numerator on the equation and then change the denominator.

Kaplan's: (|Vfl| - |Vnl|)/|Vnl|

EERM: (Vnl-Vfl)/Vfl

Don't know. Think that was a cheap way to try to be different. I did not put too much thinking on that. Don't give too much of your effort John. Pick one and stay with it.

Just a comment: I think Kaplan is very good because it makes you work concepts during the problems. For me it was the difference. I have always said that the problems are not PE Test style. But you work these problems and I can tell your chances to pass increase a lot. There might be a lot of typos and their rounding might be tricky but the important thing is the concept. I did not put attention to these details. If I was sure that if I followed my problem solving process well and applied my concepts properly I knew I had my results right, no matter what the book said.

I support Benbo's post. Stay with EERM's method for this one.


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## jdd18vm (Oct 7, 2007)

i think it has to do with terminology. what is the No load Voltage what is the Full load Voltage?

if you recall or can picture a the simplified synch motor circuit the Voltage at the terminals in this problem is 132.8 volts. The calculated emf voltage (E) generated is 248V. In Schaums they use the terms Vo to be E (i think) and Vt to be voltage across the terminals. Their VR is Vo-Vt/Vt which matches Kaplans Full load and No Load description so 248-132.8/132.8=86.8%

If i use the EERM formula 132.8-248/248=46.5 %

John


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## benbo (Oct 7, 2007)

I think the important thing is that it seem like you have a good understanding of the problem, better than me at this point. You are well on your way to passing, I think.


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## jdd18vm (Oct 7, 2007)

benbo said:


> I think the important thing is that it seem like you have a good understanding of the problem, better than me at this point. You are well on your way to passing, I think.



Well I don't know about that, but I again thank you for your vote of confidence.

I have seen your comments and Luis's about Kaplan, I do like they way they take you through stuff, but dammit it is filled with mistakes that I spend more time trying to understand if its a mistake or something I'm not getting. I cant afford the wasted time.

Another on problem 1.35 solution page 74 wtf is 227.962? should be 277.962 and yield an answer of 28.66/_-41.14 Amps? Regardless where does this formula come from?

John


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## Flyer_PE (Oct 7, 2007)

jdd18vm said:


> I have seen your comments and Luis's about Kaplan, I do like they way they take you through stuff, but dammit it is filled with mistakes that I spend more time trying to understand if its a mistake or something I'm not getting. I cant afford the wasted time.
> John


John,

I wouldn't think of it as wasted time. I had a class in college where the professor was prone to errors in the homework problems. It forced me to learn the problems backwards and forwards. It was a PITA but come test time, I had the material down cold. From the questions you're asking, you're obviously putting the required effort into this thing. You'll do fine on the test.

Now my take on the regulation question: The value in the denominator is going to be a "base" value. It's a percent difference equation. The question you have to ask yourself is: What value do I want to find the percent difference from? It will vary based on the question asked.

My :2cents:

Jim


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## benbo (Oct 8, 2007)

jdd18vm said:


> Well I don't know about that, but I again thank you for your vote of confidence.
> I have seen your comments and Luis's about Kaplan, I do like they way they take you through stuff, but dammit it is filled with mistakes that I spend more time trying to understand if its a mistake or something I'm not getting. I cant afford the wasted time.
> 
> Another on problem 1.35 solution page 74 wtf is 227.962? should be 277.962 and yield an answer of 28.66/_-41.14 Amps? Regardless where does this formula come from?
> ...


I wish I had the book still so I could help. The truth is there is nothing magical about Kaplan - it is just a more challenging practice test than the "the other board" tests. But if you feel it is frustrating you and wasting your time there is no reason to force yourself to use it. The only really critical practice exam, IMO, is the NCEES practice test. Every person is different, and as a person who has recommended this Kaplan test on the board, I didn't want to give the impression that it was an irreplaceable reference. Just one of the few practice tests around,


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## jdd18vm (Oct 9, 2007)

benbo said:


> I wish I had the book still so I could help. The truth is there is nothing magical about Kaplan - it is just a more challenging practice test than the "the other board" tests. But if you feel it is frustrating you and wasting your time there is no reason to force yourself to use it. The only really critical practice exam, IMO, is the NCEES practice test. Every person is different, and as a person who has recommended this Kaplan test on the board, I didn't want to give the impression that it was an irreplaceable reference. Just one of the few practice tests around,


Oh youre right Benbo, and you DO help. Thanks for that. I am going to concentrate these last day working PPIs and NCEES exams. I will need your help on the ECC stuff. My fear now is i didnt spend enough time on all that. I feel a little better on the power stuff.

John


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