Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Need Equation

  1. Jun 25, 2005 #1
    i am looking for an equation (integral) , so that i can predict what width to make a coil of wire , of certain length ,and thickness, so that it comes out to an outer diameter of 1.5" with an inner diameter of .5"..
    i usually spend my time in the engineering section , but i thought that i would come to you , with this question..
  2. jcsd
  3. Jun 26, 2005 #2


    User Avatar
    Science Advisor

    Here's what I would do: The volume of the "hollow" cylinder of inner radius r1 and outer radius r2 and height W (it's really the width of the coil) is [tex]\pi W(r_2^2-r_1^2)[/tex] which with r2= 1.5 and r1= 0.5 is [tex]\pi W(2.25- .25)= 2\pi W[/tex]. The volume of a length of wire of radius R and length L (a very thin cylinder) is [tex]\piLR^2[/tex]. Set those equal and solve for W: [tex]W= \frac{R^2L}{2}[/tex].
    Last edited by a moderator: Jun 27, 2005
  4. Jun 27, 2005 #3
    thats not close to what i am getting ... by your equation , it comes out to .44376 " ...
    i started winding with a width of 0.6" , and due to the tightness of my winding , it bulged out to 0.7 " tward the outer windings..
    My wire diameter is 0.043 " , pretty thick wire..
    and the reason i need to calculate the width is because my wire comes in certain lengths , specificly 480" .. and i would like to use all the wire for each coil that i am winding..and the inner & outer diameter have to be 0.5" & 1.5" respectively, so the only thing i can vary is the width..
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook