Author Topic: benchtop gap (electro) magnet  (Read 701 times)

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Offline ChristofferBTopic starter

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benchtop gap (electro) magnet
« on: August 20, 2020, 07:43:00 pm »
Hi all!

I'm currently constructing a ~3500 Gauss magnet for some physics shennanigans, and I'd like some pointers.

General topology should be similar to this:


So a yoke holding 2 pole pieces, and either coils or permanent magnets. Field strenght should be ~3500 G (0.35T), over at least a 5 mm^2 area. Preferably 10 mm^2. The gap between the poles must accomodate a section of WR-90 waveguide (narrow side).

Here's the most important design criterion: It CAN NOT be a hulking monster that draws 3 kW, needs water cooling and weighs tonnes.



I can't decide whether to go with electromagnets or permanent NdFeB magnets, in the latter case, a tune coil is also needed to be able to move the field strenght slightly.

Either way, multiple sets of smaller coils for field modulation will be introduced lastly, possibly epoxied to the pole pieces.

There's a brilliant software package called FEMM to simulate magnetic fields, that could be used to rough in dimensions.

I'd also like to have the yoke be fabricatable without needing to get a machine shop involved.

What do you think? Electro or electro tuned permanent?

Thanks in advance.
« Last Edit: August 20, 2020, 09:16:51 pm by ChristofferB »
--Christoffer //IG:Chromatogiraffery
Check out my scientific instruments diy (GC, HPLC, NMR, etc) Channel: https://www.youtube.com/channel/UCZ8l6SdZuRuoSdze1dIpzAQ
 

Offline ChristofferBTopic starter

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Re: benchtop gap (electro) magnet
« Reply #1 on: August 20, 2020, 09:47:01 pm »
I've salvaged a large 3.5 cm thick toroidal transformer core, unfortunately it is one long piece of steel band - I'd thought about either drilling through it to hold it together or put some radial welds down each side. Would this provide a viable yoke, or should I scrap that idea?
--Christoffer //IG:Chromatogiraffery
Check out my scientific instruments diy (GC, HPLC, NMR, etc) Channel: https://www.youtube.com/channel/UCZ8l6SdZuRuoSdze1dIpzAQ
 

Offline ChristofferBTopic starter

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Re: benchtop gap (electro) magnet
« Reply #2 on: August 20, 2020, 09:59:53 pm »
Alternatively something like this:

The slight gap beneath each magnet could of course be filled somehow.
--Christoffer //IG:Chromatogiraffery
Check out my scientific instruments diy (GC, HPLC, NMR, etc) Channel: https://www.youtube.com/channel/UCZ8l6SdZuRuoSdze1dIpzAQ
 


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