1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Need help about reactor (inductor)

  1. Jul 26, 2013 #1
    Can someone help me solve this? I don't really understand how to do this.

    A 1kvA reactor's capacity is needed to be enlargedto 81kvA. How much does its dimension needs to be multiplied?

    Hint:
    when its dimension is m times enlargened, surface A'=m'A, flux ∅'=m^2∅, current I'=m^2I, voltage E'=m^2E, Capacity E'I'=m^4EI.

    Loss Pe'=m^3Pe
    Temperature θ'=loss/surface area = (m^3Pe)/m^2A = mθ

    My attempt:
    Capacity E'I'=m^4EI. So,
    E'I' / EI = m^4
    81/1 = m^4
    m = 3.

    Is the answer 3?
     
    Last edited: Jul 26, 2013
  2. jcsd
  3. Jul 27, 2013 #2

    Simon Bridge

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member
    2016 Award

    Looks like a straight scaling to me too.
    It helps if you lay it out formally:

    If capacity is given by ##\small C=EI##
    And you know the E and I scale by: ##\small E'=m^{\tiny 2}E## and ##\small I'=m^{\tiny 2}I##; then $$C'=E'I'=m^4EI=m^4C$$
    The only way you can get this wrong is if any of these relations are wrong, or if you hit the wrong buttons on your calculator.

    Your answer is saying you need to increase the characteristic dimension of the reactor to 3x it's current size to get an 81x increase in capacity.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted



Similar Discussions: Need help about reactor (inductor)
Loading...