Will a solenoid inside another solenoid increase its strength?

Click For Summary
SUMMARY

Placing a solenoid inside another solenoid can increase the overall magnetic field strength, but only under specific conditions, such as connecting them in a series or parallel-aiding configuration. The superposition principle applies, where magnetic inductions add vectorially, but the increase in strength is not straightforward due to the nonlinear properties of iron cores. The National High Magnetic Field Laboratory achieves field strengths of 45 Tesla using nested coils, demonstrating the effectiveness of this method when properly implemented.

PREREQUISITES
  • Understanding of Ampere's Law
  • Knowledge of the superposition principle in electromagnetism
  • Familiarity with solenoid design and construction
  • Basic concepts of magnetic saturation in ferromagnetic materials
NEXT STEPS
  • Research the superposition principle in electromagnetism
  • Study the effects of magnetic saturation in iron cores
  • Learn about solenoid configurations and their impact on magnetic fields
  • Explore hybrid magnet technology used at the National High Magnetic Field Laboratory
USEFUL FOR

Electrical engineers, physicists, and hobbyists interested in electromagnetism, solenoid design, and magnetic field optimization.

Matt01
Will placing a solenoid inside another solenoid increase it's over all strength?

While doing research into solenoids I came across the MagLab (The National High Magnetic Field Laboratory) where they place coils one inside another to bolster the field, and reach upwards of 45 Tesla. They use an air core, high number of turns, and 30 mw to achieve this.
(Note: I know that no material can achieve any way near 45 Tesla. looking to increase the field strength of realistically week fields. )
My question is, can the same be done for iron cores?
Example:
All aspects of the cores will be the same except the Diameters and internal geometry/volume.

Length of 12 inches/304.8mm

300 turns

relative permeability of the core is 5000

.2 amp

1 Tesla let's say will be the max field strength.

The first rod has a diameter of 2 inches/50.8mm

with wiring and insulation it's total diameter is 2.5 inches/64 mm

The second iron rod has a diameter of 4.5 inches/114.3mm

From the center of the second we remove 2.5 inches/ 64mm and bore straight though the iron rod essentially creating a pipe so we can place the first solenoid inside the second one. The length has not increased both are still 12 inches/304.8mm. There would be a very small amount of air the the field would pass though due to the second solenoid occupying the space.

Could this method work in increasing the field strength from 1 Tesla to 2 Tesla?
Would there be any increase in the strength of the combined solenoids?
Is there a way to determine what the increase would be if there is one?
(Note: Wondering what the strength would be at the end face if it would reach 2 tesla.)
 
Physics news on Phys.org
Matt01 said:
Will placing a solenoid inside another solenoid increase it's over all strength?
Yes, but only if they are connected in series/parallel-aiding fashion.
 
Last edited:
What do you know about the superposition principle?
 
Nothing. I received another message and I'll share it with you citing the superposition principle. I am getting ready to dive into it.

"The short answer to your question is that you can increase
7_69e3966668f4dabe833bedf0903ccb0c.png
but not for the reasons you think. If you put a solenoid inside another solenoid and you apply Ampere's law, you will find that the magnetic inductions add vectorially. The effect is known as "superposition of effects"."
 
So i found this while looking into the superposition principle:



The question is since one is inside the other, would I still need to take into account the vectors or does the math simplify to B total = B1+B2?
 
The fields inside nested air-core solenoids add. Iron is highly nonlinear and once it reaches saturation, gains are small. (1T is far beyond iron's saturation induction.) So yes, field strength increases, but no, it's not simple superposition.
 
  • Like
Likes   Reactions: Charles Link

Similar threads

  • · Replies 2 ·
Replies
2
Views
3K
  • · Replies 6 ·
Replies
6
Views
2K
  • · Replies 43 ·
2
Replies
43
Views
7K
Replies
9
Views
2K
  • · Replies 5 ·
Replies
5
Views
4K
  • · Replies 5 ·
Replies
5
Views
5K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 3 ·
Replies
3
Views
6K
  • · Replies 16 ·
Replies
16
Views
2K
  • · Replies 1 ·
Replies
1
Views
3K