# CI Test #1 & Test #4



## bethy (Mar 23, 2013)

Why the voltage drop formula to solve these two problem using the "subtract":

V(d) = I * {R*cos(theta) - X* sine(theta)} * L/1000

From table 9, NEC book. It is shown as ( + ). Can some one explain to me please??

Thanks,


----------



## bethy (Mar 23, 2013)

bethy said:


> *Oop! Forgot to tell you the problem number; In CI test #2 problem 10 and Test #1 - problem 48*. Why the voltage drop formula to solve these two problem using the "subtract":
> 
> V(d) = I * {R*cos(theta) - X* sine(theta)} * L/1000
> 
> ...


----------



## Raiden (Mar 24, 2013)

i am looking at my CI version of the book and tthe answer shows + instead of the - you mentioned. Maybe you have an older version.


----------



## bethy (Mar 25, 2013)

Rtaiden,

The test was 2011. So it's maybe a error. Would you please give me the answer of those problems with the (+) sign. The one I got the answer goes with th (-) sign. Thanks.

I wonder that Josh had post the correct error on the CI website??


----------



## Raiden (Mar 26, 2013)

Josh has posted this "Errata" on the website. I have found some other issues that I feel that are errors on the 2012 version. 

CI Test #2 Problem 10 Answer: VP = 40 * [0.34 cos (-10) + 0.023 Sin (-10)] = 13.2V then (13.2V/120) * 100 = 11.0%

CI Test #1 Problem 48 Answer: V(d) = I * {R*cos(theta) + X* sine(theta)} * L/1000 =


----------



## EItoPE (Apr 1, 2013)

Raiden said:


> Josh has posted this "Errata" on the website. I have found some other issues that I feel that are errors on the 2012 version.
> 
> CI Test #2 Problem 10 Answer: VP = 40 * [0.34 cos (-10) + 0.023 Sin (-10)] = 13.2V then (13.2V/120) * 100 = 11.0%
> 
> CI Test #1 Problem 48 Answer: V(d) = I * {R*cos(theta) + X* sine(theta)} * L/1000 =


Could anyone please direct me to this "Errata" on Complex Imaginary website? Thanks in advance!


----------



## SureLikeStudying (Apr 1, 2013)

EltoPE,

Not sure it on their website, I've looked too.

Anyone have a copy of the version 2 errata?

Thanks.


----------



## poosri (Apr 4, 2015)

So the correct formula is R cos(theta)+ X sin (theta) regardless of lagging or leading pf, correct?


----------

