Increasing Inductance with Iron Core?

[amanno]

If I wrap a wire around a permanent magnet (iron) to make an inductor... will that increase the strength of the inductance? Or just push the inductor into magnetic saturation?

What if I just use a solid ferromagnetic core (not magnetized) such as an iron or steel rod? How much does that increase inductance over an air coil inductor?

Thanks for the help!

 

[0xDEADBEEF]

The factor how much the inductance increases is called magnetic permeability http://en.wikipedia.org/wiki/Permeability_(electromagnetism) for steel it is about 100. For everything else you should read about magnetic hysteresis.

 

[davenn]

hi amanno,
welcome to PF :)

Reading your post, I am still trying to decide if you have a bit of a misunderstanding about an iron cored inductor

If I wrap a wire around a permanent magnet (iron) to make an inductor... will that increase the strength of the inductance? Or just push the inductor into magnetic saturation?

I can't think of any example in any electronics I have ever worked on where the iron core is already a permanent magnet. I can't think of any good reason why you would want to do that. As the magnetic field would work against the the magnetic field being generated by the coil when a current passes through it.

What if I just use a solid ferromagnetic core (not magnetized) such as an iron or steel rod? How much does that increase inductance over an air coil inductor?

Inductors come in 2 usual styles ...
1) -- air core and a
2) -- ferromagnetic core (not magnetized) it can be either laminated or a ferrite powder as is commonly used in transformers or solid iron core as usually used in an electromagnet for say a relay or solenoid

using a ferrite, laminated or solid iron core has the effect of concentrating the magnetic field within the core and coil. The iron type core can increase the inductance by a factor of 1000 or more over an air cored inductor

Laminated or ferrite / fericeramic cored materials are used to decrease ot stop the generation of eddy currents within the core.


cheers
Dave