Inductive Reactance of Solenoid as function of frequency.

Thread Starter

Stoyan.Nikolov.2Induction

Joined Nov 26, 2023
14
inductive Reactance of Solenoid with Solid Metal Core With respect to frquency
Hi. Consider the Solenoid/Inductor Like one the Picture. There is Air gap between the coil and inserted solid metal.

Hi. Consider the Solenoid/Inductor Like one the Picture. There is Air gap between the coil and inserted solid metal. The solid metal is from Aluminum or Copper (Both have relative magnetic permeability , close to 1 regardless of temperature).

What will happen with inductive reactance of the given Solenoid if we increase the frequency of the applied voltage.

Thank you.

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k1ng 1337

Joined Sep 11, 2020
960
Hi, inductive reactance increases with an increase in frequency. Whether or not the core saturates depends on the current and the core material.

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1384947040PSDB_1211_TF06_Renco_fig2.jpg
 

Thread Starter

Stoyan.Nikolov.2Induction

Joined Nov 26, 2023
14
Please consider also the induced Eddy currents in the solid metal core.
Hi, inductive reactance increases with an increase in frequency. Whether or not the core saturates depends on the current and the core material.

View attachment 312715
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Thank you for the answer. Consider solid metal core with constant relative magnetic permeability that doesn't change with temperature. Such mre Aluminium or Copper with relative magnetic permeability close to 1 and doesn't change with temperature (and perhaps doesn't exhibit magnetic saturation ,hysteresis and other unwanted magnetic properties)
 

k1ng 1337

Joined Sep 11, 2020
960
Please consider also the induced Eddy currents in the solid metal core.

Thank you for the answer. Consider solid metal core with constant relative magnetic permeability that doesn't change with temperature. Such mre Aluminium or Copper with relative magnetic permeability close to 1 and doesn't change with temperature (and perhaps doesn't exhibit magnetic saturation ,hysteresis and other unwanted magnetic properties)
Eddy currents are a complex topic. Is this for induction heating?

In the case of a copper vs aluminum core, the copper will exhibit less heating due to Eddy currents because it has greater electrical conductivity. This is oversimplified because there are many factors which must be taken into consideration such as the dimensions of the core.

Are you familiar with Lenz's Law and Faraday's Law of Electromagnetic Induction? If not, these are a good place to start.

Also check out this article for some relevant information:

https://www.twi-global.com/technical-knowledge/faqs/faq-what-factors-affect-eddy-currents
 

MisterBill2

Joined Jan 23, 2018
18,519
Inductive reactance increases linearly with frequency. But inductance is affected by magnetic saturation and to some extent, by temperature.
And for a solenoid that closes an air gap, the inductance changes rapidly as the solenoid air-gap is closed. That change does have a very profound effect on the current drawn by a solenoid coil as the solenoid moves to close the air-gap..
 
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