# Confused about electromagnet?

by 215
Tags: confused, electromagnet
 Share this thread:
 P: 39 How do i calculate the magnet field for an Solenoid with an ironcore with x windings and y amps.. The same for an horseshoe magnet, where there is an air gap about 2mm.. For some reason does my calculation not make sense..
Mentor
P: 11,921
 Quote by 215 For some reason does my calculation not make sense..
It would be easier to look for a mistake if you added your calculations here.
 P: 39 ohh sorry my bad.. I have choosen to use 1A as constant. For the Horseshoe magnet B = $\frac{i*n*µ0*µr}{lj+2vµr+2xµr}$ lj = length of the ironcore = 0.034+0.011+0.034 µ0 = 4pi *10^-7 x= length of one of the airgaps v= length of the other airgap µr = Relative permability = µ0(1+XM)=5000 I = 1 For the solonoid B = µrH H=$\frac{N*I}{l}$ l = 0.065 I = 1 I know B = 0.4 I've been trying to solve for N, windings, and for the solonoid do i get 22, and for the horseshoe do i get 1688..
Mentor
P: 11,921
Confused about electromagnet?

 Quote by 215 I've been trying to solve for N, windings, and for the solonoid do i get 22, and for the horseshoe do i get 1688..
And where is the issue with those solutions?

I don't understand the horseshoe geometry with multiple (4?) air gaps.
 P: 153 looks like a homework problem. move to other thread??
 P: 39 Homework... Well, is more like a project.. I am trying to build an Electromagnet which capable off pulling a certain amount of newton.. I done conversion from Newton to Tesla... Now do i have define the tesla value.. http://snag.gy/oL7D5.jpg
 P: 153 horseshoe magnet will have only one air gap. how come you have 4? please draw the detailed diagram of the magnet.
 P: 39 Here is a picture of the one I've been working with http://snag.gy/A7zJd.jpg There is an airgap between each leg, each leg has to pull a piece of metal with 3N, in the distance of 2 mm, i am quite unsure about the next one, but would the airgap between the the metal pieces have something to say?

 Related Discussions Electrical Engineering 6 Electrical Engineering 2 General Physics 0 Electrical Engineering 16 General Physics 2