YBaCuO + magnet + electromagnet levitation 1

[magone]

Good afternoon.from France
I would like to increase the levitation forces, usually 5/10 N/cm2 between a NdFeB and a bulk HTS, but at reasonnable price and current because in our techno we need 24 to 100 systems per machine.
Here some technical explanations.
PM size 50*50 mm thick "free" + ferrous material
HTS size 40*25*12
gap 5 to 8mm
PM is the levited part
2 HTS is mounted on the housing and faced on every side the PM and cooled with nitrogen.
I red several publications on "trapped fiel magnets system" but every time the cost is prohibitive.
In our case with a gap in the configuration described , already optimised, i got, for a gap 5 mm, a shear force of 30N in Y axis.
if i could add a electromagnet behind HTS, it seems possible to increase the magnetic field.
I would like to get a shear force and lateral *3 at same gap and size.
Does anybody can tell me what current is necessary and a idea of prices for electromagnet.
Does anybody can tell me if an other solution exists?
Many thanks for your cooperation

 

[MagMike]

Hello magone,

That's an interesting challenge.

I don't believe placing an electromagnet behind the HTS (opposite side of the permanent magnet) will help. The flux lines from the electromagnet will be repulsed by the HTS, and won't do anything to reach/help the permanent magnet.

As near as I can tell, you need to increase the field from your permanent magnet and I don't think it'll be easy to acheive 3x increase in force without going to much larger magnets.

I would suggest using the strongest grade of NdFeB material, such as 52 MGOe (413 kJ/m^3) and as large a size as you can obtain/afford. Also, if you can chill the NdFeB with some of the liquid nitrogen, that'll help boost the output as well. Just make sure the NdFeB stays above 135K, else it'll start to weaken.

Isn't there an upper limit on the amount of magnetic field that a HTS can repel? Are you close to that level now?

 

[IRstuff]

http://hyperphysics.phy-astr.gsu.edu/hbase/solids/maglev.html

TTFN