Magnetic Flux analysis in transformer design.

[JJ91]

Hello everyone,

I'm currently at third year of EPE and this software is totally new for me so i would to ask a few questions.

I have been asked to use infolytica MagNet using Field Sampler tool to analyse a flux behavior in the air-gaps and in the transformer core for 2 different core materials, 2 different coil materials and 5 different current ratings (2,4,6,8,10 amps).

The design shows as follows:

I've got most of my graphs and its now coming to write conclusion but there is 1 graph where I think something went wrong:
(the graphs represent the flux in the airgap or the 'c' point from the above diagram measured from TOP to bottom)

AGmid - Airgap in the middle of the core (between secondary winding)
ALU - aluminium (coil material)
COP - copper (coil material)
MU3 - Core material (lower than CR10)
CR10 - Core material (higher permeability than MU3)

http://www.2shared.com/file/WrczYYFS/Correct_Reults.html"
The air-gap in the middle of the transformer core and the B_x line is straight where I'm afraid it shouldn't be.

1. So I would to ask what went wrong and where should I look for mistake ?

2. Why there is a difference of direction between MU3 and CR10 from the above graphs ?

3. What else can I say from the graphs apart what is the strength, leakage, direction and magnitude of the flux in specific area ?

I'm asking here because report is due to in Monday,

Thanks a lot for any additional information

 

[Bob S]

You need to give us more information. The corners at "c" are very likely to saturate first, much sooner than the center of the air gap. The air gap (20 mm) will have a significant effect on the inductance because the outside path length (each side) is only about 1400 mm.

So, what are the units of the vertical scale in the plots? They are too low to be magnetic field (in Tesla). And what are the horizontal units (where measured)? And what do the different colors in the plots represent, different amp-turns total or amps per turn? Is the transformer secondary open, or connected to a load? Aluminum will have a greater I²R loss than copper for the same cross section.