# Magnetic permeability and magnetic resistance

1. Jun 10, 2006

### kievstar

hi from ukraine
i'm a electronic engineering student at kiev polytechnic university
how can i calculate this question
The steel winding with the number of coils w= 200 is put on thr ring-like closed
core in regular intervals.The section is rectangular. The external diameter of a ring
D=16 sm, the interval diameter d=10 sm, thickness b=4 sm.Magnetic induction B in
the core have to be equal 1 T1. How will current and magnetic resistance changes,
if the nonmagnetic (air) 'interval b=0.5 mm would be made. Magnetic flux has to be
constant.Define the relative magnetic permeability and magnetic resistance of the
ferromagnetic steel and sheet steel 1512 cores, if the magnetic flux in the interval
(theta)=1.2x1/1000 Wb. Dependence B(H) for steel is approximate to a such data:
0,2(80)0,4(185)0,6(300)0,8(460)1,0(750)1,2(1500)
http://www.technick.net/public/code/...nce_calculator [Broken]
but i couldn't calculate

Last edited by a moderator: May 2, 2017
2. Jun 10, 2006

### Gokul43201

Staff Emeritus
kievstar, I don't understand the setup. Do you think you can attach a picture?

3. Jun 12, 2006

### kievstar

thanks for your interest i'll attach as soon as possible

4. Jun 12, 2006

### kievstar

i gues one of theese is about with my question
i say guess because tehre is no given picture with questions

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5. Jun 12, 2006

### Staff: Mentor

Sounds like it's a square cross-section toroidal core, with ID=10cm and OD=16cm, with 300 turns of wire. The question is asking about the change in reluctance when an air gap is introduced. I don't get the part about "Magnetic induction B in the core have to be equal 1 T1." Maybe the attachments will clear that up when they get approved.

6. Jun 13, 2006

### kievstar

thanks so much berkeman
i found a site about the point that you say reluctance change when air gap introduced
http://homepages.which.net/~paul.hills/Solenoids/SolenoidsBody.html" [Broken]

Last edited by a moderator: May 2, 2017
7. Jun 13, 2006

### kievstar

anyone to help?

8. Jun 13, 2006

### Staff: Mentor

Oh, sorry, from your last post I thought you had it figured out. Please post your work so far, and I'll take a look at it. What part are you having trouble with? What does your textbook say about air gaps?

9. Jun 14, 2006

### kievstar

don't worry i calculated yesterday:rofl: