high power electromagnet >3kW / Electromagnetic Radiation / Forums

Forums

4hv.org :: Forums :: Electromagnetic Radiation

« Previous topic | Next topic »

high power electromagnet >3kW

1 2 next

Move Thread

LAN_403

Reaching

Fri May 12 2006, 01:40PM

Registered Member #76 Joined: Thu Feb 09 2006, 10:04AM
Location: Hemer, Germany
Posts: 458

within the next weeks i want to build a huge electromagnet for various experiments. with a 10mm Bore inside(10mm aluminium, 8mm inside) and an outside diameter of approx 100mm. to get a high density i wanted to use the smallest wire possible for around 16A at 230Volts(0,5mm)Dc. The coil will be watercooled to allow a few minutes of runtime.

do you think it is possible or am i totally wrong'?
is anyone expierienced in building higher power electromagnets?maybe someone is interested to make a femm analysis, im not expierienced in Femm.-

Marko

Fri May 12 2006, 03:35PM

Registered Member #89 Joined: Thu Feb 09 2006, 02:40PM
Location: Zadar, Croatia
Posts: 3145

For DC you can simply find biggest piece of iron around for a core.
Windings will also give only DC resistance so you can put a lot of current into the magnet ( depending how much power can you draw from it)

I think Tesladownunder owns one such a big magnet here.

Sulaiman

Fri May 12 2006, 06:31PM

Registered Member #162 Joined: Mon Feb 13 2006, 10:25AM
Location: United Kingdom
Posts: 3140

I haven't built such a device,
but from other experience I suspect that the 'best' configuration is a 'brooks coil'
Just a name for a multi-layer coil giving maximum inductance/resistance.
This is for an air-core inductor.

Probably the best places for ideas are
NMR electromagnet technology
or

the home of magnetically levitated frogs

Simon Barsinister

Fri May 12 2006, 10:13PM

Registered Member #116 Joined: Fri Feb 10 2006, 03:19AM
Location: Erie Pa, USA
Posts: 29

Wind it with the core winding 1 wire size smaller than the outer one. That is how they make the really big ones. Think amp-turns and losses. It's a lot more wire per turn at the outer parts.
Rich

Reaching

Sat May 13 2006, 07:44PM

Registered Member #76 Joined: Thu Feb 09 2006, 10:04AM
Location: Hemer, Germany
Posts: 458

yeah, i wanted to build one of these magnets , called bitter magnets , flying frogs etc. but i dont have the equipment to construct these copper plates etc. so i thought about a simple "normal" coil with a 10mm Bore inside so i can put pieces inside and make my experiments with it.

i want the highest magnetic field possible with around 3,6kW of power. i have the equipment to build a dc powersupply with around 3volts and 1kA Dc that would give me the highest magnetic field possible, but is it good enough or powerful enough for my needs? (around 1-2Tesla, hopefully)or should i go with more voltage and less current ,btw whats the best configuration ,voltage,current for a high field strenght electro magnet?
,thanks for the answers

Sulaiman

Sat May 13 2006, 09:29PM

Registered Member #162 Joined: Mon Feb 13 2006, 10:25AM
Location: United Kingdom
Posts: 3140

If you are aiming for 1 to 2 T
then use transformer lamination steel for 1.8 T saturation flux density
the iron core will reduce required amp.turns for a given flux density.
Use as short an airgap as possible.

Above this flux density iron/steel saturates so is no help - air core required.

'square' wire or foil will give more amps/square-meter in the coil
giving more Tesla/amp.

I^2.R losses / heat will be the limitation for an air core magnet
so
1)
The optimum power supply is Vdc = Idc x Rcoil
2)
Short ON times with longer cooling-down OFF times will give highest flux density
so do you need a continuous magnetic field?

McFluffin

Sun May 14 2006, 12:23PM

Registered Member #119 Joined: Fri Feb 10 2006, 06:26AM
Location: USA
Posts: 114

I think most of these are pulsed power magnets, but I have a book called "The Internation Symposium of Magnet Technology." An older book(1965), but its on building high power magnets for particle accelerators. Maybe I could post the table of contents and, if a specific paper interested you, I could scan it and send you a PDF.

OScoder

Sun May 14 2006, 04:05PM

Registered Member #304 Joined: Sat Mar 11 2006, 02:19PM
Location:
Posts: 5

one possible problem I saw:
Where are you going to get the power from?

Sulaiman

Sun May 14 2006, 06:53PM

Registered Member #162 Joined: Mon Feb 13 2006, 10:25AM
Location: United Kingdom
Posts: 3140

Using dc
the stored magnetic energy will be massive,
so expect a humungous 'flyback' spike on switch-off
and use a suitable 'freewheel' diode to 'catch' the kickback.

P.S. 220 Vac full-wave rectified gives about 300 Vdc
300 V @ 10 Adc would require the same weight of wire as 3V @ 1 kAdc
for the same magnetic flux and volume
but needs 10x less cross-sectional area wire,
easier to find and wind,
And easier design of power supply
and easier to find 10 A diode than 1 kA diode.

Hazmatt_(The Underdog)

Tue May 16 2006, 02:01AM

Registered Member #135 Joined: Sat Feb 11 2006, 12:06AM
Location: Anywhere is fine
Posts: 1735

look at this badboy

Super cool!

Probably an EMP test fixture, what else could it be anyways.

Now all you need are many large cap banks and switchgear, say 100 banks, each pulsed into that fixture and you got it!

heheheh.

1 2 next

Moderator(s): Chris Russell, Noelle, Alex, Tesladownunder, Dave Marshall, Dave Billington, Bjørn, Steve Conner, Wolfram, Kizmo, Mads Barnkob