Buzzing
Member
Hello gentlemen and ladies alike,
I'm priming to take my 2394 and 2395 also with some hope, later maybe the 2396. On side note has anyone done this? What is to be expected? What is it's worth?
Anyway back to what i started this thread for. As i said i've been brushing up on regs GN3 test procedures ect...But as you can guess i get easily distracted.
To the point that i decided to go through my old course notes and books and found a electrical calcs book with exercises and thought ill see if i can still do them.
I found i could until i got to one that should be easy, and no doubt someone/people will tell me my errors but i can't seem to get the given answers in the back of the book.
So for those that are interested, here's the question-
A reactor allows a current of 15A to flow from a 230v, 50Hz supply.
Determine the current which will flow at the same voltage if the frequency changes to
A) 45Hz, B)55Hz.
Ignore the resistance.
My calcs are as follows-
U/V=XL
XL=2
fL
So, 230/15=15.333
15.333/(2x
x50)=0.0488H
And so, 2x
x50x0.0488=15.33.
So that bit works out ok.
As far as i can work out i just have to change to the desired frequency to work out the current change.
2x
x45x0.0488=13.79ohms
230/13.79=16.67A (book answer = 15.97A)
Same again with higher frequency i get 13.64A (book answer 13.07A)
I've tried the calc again using the alternate Hz to attain the H, but this didn't work out neither.
I don't know why i'm so bothered, i shouldn't care less, but i do, i hate admitting defeat, as in the past i would have had to work this out.
Unless the book is wrong, it which case it'll be smoked....
Am i asking to be flamed? i wonder.....
I'm priming to take my 2394 and 2395 also with some hope, later maybe the 2396. On side note has anyone done this? What is to be expected? What is it's worth?
Anyway back to what i started this thread for. As i said i've been brushing up on regs GN3 test procedures ect...But as you can guess i get easily distracted.
To the point that i decided to go through my old course notes and books and found a electrical calcs book with exercises and thought ill see if i can still do them.
I found i could until i got to one that should be easy, and no doubt someone/people will tell me my errors but i can't seem to get the given answers in the back of the book.
So for those that are interested, here's the question-
A reactor allows a current of 15A to flow from a 230v, 50Hz supply.
Determine the current which will flow at the same voltage if the frequency changes to
A) 45Hz, B)55Hz.
Ignore the resistance.
My calcs are as follows-
U/V=XL
XL=2
So, 230/15=15.333
15.333/(2x
And so, 2x
So that bit works out ok.
As far as i can work out i just have to change to the desired frequency to work out the current change.
2x
230/13.79=16.67A (book answer = 15.97A)
Same again with higher frequency i get 13.64A (book answer 13.07A)
I've tried the calc again using the alternate Hz to attain the H, but this didn't work out neither.
I don't know why i'm so bothered, i shouldn't care less, but i do, i hate admitting defeat, as in the past i would have had to work this out.
Unless the book is wrong, it which case it'll be smoked....
Am i asking to be flamed? i wonder.....
