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1106 views
05:48 May-24-2006
Ranjeet singh
Differance between Ferrite magnetic permeability

I would like to know expert views about the differance between magnetic permeability and ferrite measurment.
Are they same ?

thanks


 
01:32 May-26-2006

Linas Svilanis

R & D,
Kaunas University of Technology,
Lithuania,
Joined Nov 1998
66
Re: Differance between Ferrite magnetic permeability ----------- Start Original Message -----------
: I would like to know expert views about the differance between magnetic permeability and ferrite measurment.
: Are they same ?
: thanks
------------ End Original Message ------------

Magnetic permeability is the parameter related to magnetic properties of the material.
Ferrite is the material.
You are asking to compare apples and melons.

Most probably you are concerned about magnetic permeability of ferrite compared to other materials.
Yes, ferrite u will be the highes. But also will exhibit the highes hysteresis. That is, u will be nonlinear function of field strength.
u is usually measured as complex value (see complex permeability), to take all the material electromagnetic interaction into account


 
02:53 May-30-2006

John Brunk

Engineering, NDT Level III
Self employed, part-time,
USA,
Joined Oct 1999
158
Re: Differance between Ferrite magnetic permeability ----------- Start Original Message -----------
: : I would like to know expert views about the differance between magnetic permeability and ferrite measurment.
: : Are they same ?
: : thanks
: Magnetic permeability is the parameter related to magnetic properties of the material.
: Ferrite is the material.
: You are asking to compare apples and melons.
: Most probably you are concerned about magnetic permeability of ferrite compared to other materials.
: Yes, ferrite u will be the highes. But also will exhibit the highes hysteresis. That is, u will be nonlinear function of field strength.
: u is usually measured as complex value (see complex permeability), to take all the material electromagnetic interaction into account
------------ End Original Message ------------

Instruments that are sold for measurement of delta ferrite content actually do measure variations in magnetic permeability. The standards used to calibrate them have their ferrite content determined by metallographic examination. The reason they are called ferrite meters is probably just because ferrite content is the most likely cause of permeability variations is the objects usually tested. This type of instrument is often more useful for testing actual welds or parts than an instrument made to measure magnetic permability of low-permability materials with greater accuracy. The latter have larger probes and require specific sample size, thickness and flatness for highly accurate readings. I have compared both of these types of instruments, a pendulum-type ferrite indicator that "brackets" a sample between two references, and an eddy current tester for a couple of applications. They all agreed with each other for sorting a set of samples with similar geometry.



 


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