Magnetic lamination thickness
Magnetic lamination thickness
(OP)
I am working on the design of an electromagnet that uses silicon iron laminations. I am looking for a formula or chart that will help me determine what the thickness of the laminations should be. The electromagnet will operate at 0-400 hz.





RE: Magnetic lamination thickness
www.googl
RE: Magnetic lamination thickness
Thinner laminations will have lower loss/temperature rise at 400 hertz.
At 400 hertz and say 4 kilogauss there will be audible noise with the noise increasing with higher flux density.
Is audible noise a concern?
In this application, does the flux density decrease with increasing frequency?
RE: Magnetic lamination thickness
RE: Magnetic lamination thickness
The transformer weighed about 100 pounds, was forced air cooled, used 0.004 inch thick laminations of silicon steel in C core and operated at 14 kilogauss. When energized, transformer howled like a banchee. (Could hear it from a block away). (If my conversions are correct, 14 kilogauss is 1.4 tesla and one block is about 201 meter)
Transformer was made with three cores, with air ducts between cores for cooling.
RE: Magnetic lamination thickness
TTFN
RE: Magnetic lamination thickness
http://www.metglas.com/
RE: Magnetic lamination thickness
I have never seen a specific formula that you can use, however lamination suppliers do supply design tables giving the watts loss per kg (or lb in the US) for a given peak flux density, usually 1.5T (15kg) and frequency.
An example :
http://www.orb.gb.com/
(if you select "brochures" from the products menu, then download the most appropriate brochure, e.g. Non-oriented, fully processed and look on page 25, the table shows the watts/kg at 400Hz for a range of flux densities). If you are in the US, there is a brochure for ASTM grades.
If you know your working flux density (note PEAK values are always used, not RMS) and the total mass of steel, you can calculate the total loss. This assumes the flux density is uniform throughout the core and it is sinusoidal.
In an electromagnet it may be possible to use oriented steel provided the flux is always in the preferred direction in all parts of the core, this is more expensive but has significantly lower loss.
You will need to design for the worst case (i.e. 400Hz), probably needing a 0.35mm grade or equivalent.
RE: Magnetic lamination thickness
Stacking factor depends on different factors, but following is probably correct for most situations.
0.014 inch thick laminations, stacking factor 0.95.
0.004 inch thick laminations, stacking factor 0.90.
Metglas laminations, stacking factor 0.80 (0.80 was give some years ago for metglas laminations)
Core will operate at 1.3 Tesla/Stacking factor
0.014 thick silicon steel laminations probably have excessive loss for this application.
When stacking factor is considered for metglas, the saturation flux density is to low and the core loss is excessive.
?This leaves the best choice being laminations of 0.004 inch thick oriented silicon steel?
RE: Magnetic lamination thickness
When we tested standard lams we only lightly clamped the stacks. When we tested 4 mil and 6 mil at 400Hz we had to bolt them together to a base plate, just for the lab test.
= = = = = = = = = = = = = = = = = = = =
Corrosion never sleeps, but it can be managed.
http://www.trenttube.com/Trent/tech_form.htm
RE: Magnetic lamination thickness
RE: Magnetic lamination thickness
RE: Magnetic lamination thickness
THIS IMPLIES DC.
WHILE OTHER PROBLEMS ARISE AT 400 HZ
THAT ARE DEPENDENT ON CURRENT, FC, WIRE SIZE,AND A FEW OTHER THINGS THESE ARE GENERAL MINIMAL AT 400 HZ.
THE UNIT MUST NOT SATURATE AT DC.
YOU SHOULD BE ABLE TO FIND A PROGRAM
TO DO YOUR SPECIFIC NEED ON THE NET.
IF NOT LET ME KNOW. YOU WILL NEED TO KNOW
MANY THINGS, SUCH AS MATERIAL (IRON OR STEEL OR AIR
AND CURRENT AND ACCEPTABLE POWER LOSSES, SIZE OF THE CORE,
ETC).
MAG-INC.COM
METGLAS.COM
MICROMETALS.COM
ARE WEB SITES YOU SHOULD TRY.