Calculating flux density in an air gap

Click For Summary
SUMMARY

This discussion focuses on calculating the flux density in an air gap of an electromagnet using a C core made of laminated electrical steel. The user is specifically working with a 50Hz AC supply and is concerned about the impact of AC impedance on the calculations. Key parameters include a core permeability of 5.0×10−3 H/m, a cross-sectional area of 1 cm2, a magnetic path length of 19 cm, and an air gap length of 1 cm, with a target flux density of 1 Tesla. The conversation emphasizes the importance of understanding the difference between DC and AC calculations, particularly regarding magneto-motive force (MMF) and impedance.

PREREQUISITES
  • Understanding of electromagnetism principles, specifically flux density calculations.
  • Familiarity with AC circuit analysis, including impedance and MMF.
  • Knowledge of electrical steel properties and their impact on magnetic circuits.
  • Experience with variacs for voltage control in AC applications.
NEXT STEPS
  • Calculate the DC current required for the desired flux density in the air gap.
  • Learn about the effects of AC impedance on electromagnet performance.
  • Explore the relationship between peak and RMS values in AC circuits.
  • Investigate the use of simulation tools for modeling magnetic circuits with AC inputs.
USEFUL FOR

Electrical engineers, electromagnet designers, and students studying electromagnetic theory who are interested in practical applications of AC circuits in magnetic systems.

escape_velocity
Messages
44
Reaction score
2
I am trying to calculate the flux density of an air gap in an electromagnet.
I am following this page that calculates the flux density in a C core with an air gap.

My confusion is that I am using 50Hz AC instead of DC I have control over the voltage amplitude since I would be using a variac to do my initial tests.

Would the calculations differ for AC, my guess is that it would be different since the AC impedance of the coil would come into play and that would change the MMF(magneto-motive force) value.

I have a C core of Electrical steel (laminated) with the following parameters
Permeabity of core = 5.0×10−3 H/m
Cross section Area = 1cm2
Magnetic Path Length = 19cm
Air Gap length = 1cm
Flux Density needed in air gap = 1Tesla

Would appreciate your thoughts on how to go about doing this calculation.
Thanks in advance.
 
Physics news on Phys.org
escape_velocity said:
My confusion is that I am using 50Hz AC instead of DC
Well, if you use a sinusoidal AC current, you will get a sinusoidal flux. The flux density is proportional to the current.

So is the needed flux density ( 1T ) the peak value, the RMS value or . . . ?

I suggest that you calculate the DC current at first. You should find the result as: amps⋅windings. The AC impedance depends on the number of windings ( and on the resistance of the windings ). Knowing the impedance and the needed current, you can calculate the AC voltage needed.
 

Similar threads

  • · Replies 3 ·
Replies
3
Views
1K
  • · Replies 43 ·
2
Replies
43
Views
7K
  • · Replies 28 ·
Replies
28
Views
3K
  • · Replies 6 ·
Replies
6
Views
2K
  • · Replies 28 ·
Replies
28
Views
6K
  • · Replies 1 ·
Replies
1
Views
4K
  • · Replies 6 ·
Replies
6
Views
2K
  • · Replies 4 ·
Replies
4
Views
8K
  • · Replies 1 ·
Replies
1
Views
7K
  • · Replies 15 ·
Replies
15
Views
3K