Fun With an Induction Cooktop? 147
fishfrys writes "Besides generating heat quickly and efficiently in ferromagnetic pans, what sorts of fun things can you do with an induction cooktop? This seems like a pretty serious piece of electromagnetic equipment — boiling water can't be the only thing it's good for. I went to YouTube, expecting to find all sorts of crazy videos of unsafe induction cooktop shenanigans, but found only cooking. What sort of exciting, if not stupid, physics experiments can be performed with one? Hard drive scrubber? DIY Tesla coil? There's got to be something."
Re:Lightbulb (Score:2, Informative)
It's a nerd site. We like to investigate, determine, build and generally fiddle.
The real question is "Why is a boring muggle like you even doing here?"
Producing high voltages isn't going to work. (Score:4, Informative)
Induction cooktops operate at a frequency of a few tens of kilohertz. Using it to excite a Tesla coil probably can't be made to work, at least, not with a reasonable number of turns on your secondary coil. The coil under the surface of the cooktop has a large number of turns.
(To step up voltage, you want a few turns on the primary, and many times as many turns on the secondary.)
Re:Lightbulb (Score:5, Informative)
Can we just go ahead and get a "-1, Goatse" mod option?
Re:Lightbulb (Score:3, Informative)
WARNING DO NOT CLICK GOATSE
Re:make aluminum foil burn (Score:5, Informative)
For much the same reason - 'magnetic stainless' is typically said to be OK for induction cooking, and 'non-magnetic' not.
This is due to the 'skin depth' (look at wikipedia) being thinner in magnetic materials.
This means that in both steel and iron pans, which are magnetic, in addition to the high resistance of the pan material, the electricity doesn't go very deeply, so it's only passing through a thin skin of the pan.
However - with very thin containers, non-magnetic stainless works just fine.
I regularly heat up a large (non-magnetic) stainless washing up bowl that's maybe 0.5mm thick on my induction cooker.
Any thicker and it doesn't work.
My favourite utensil to use with it is actually a cheap 0.8mm or so thick steel wok.
Heats up in seconds, and once seasoned, is quite non-stick.
My second favourite is a large steel plate 6mm thick, again seasoned.
Mine goes up to 11 ... (Score:4, Informative)
My stove has levels that go up to 11. It's from Functionica. Whenever I get a visit from someone from the US, who has seen Spinal Tap, I show it to them and they laugh their asses off.
Re:Lightbulb (Score:4, Informative)
Can we just go ahead and get a "-1, Goatse" mod option?
Perhaps we could get /. to display the dereferenced URL instead of bit.ly, etc. -- hardly rocket science (don't click on any of these, obviously...):
/dev/null http://bit.ly/d9LffL [bit.ly] 2>&1 | grep -o 'http[^ ]*'
user@host:~$ wget -O
http://bit.ly/d9LffL [bit.ly]
http://goatse.fr/ [goatse.fr]
http://goatse.fr/ [goatse.fr]
Re:water balloon (Score:5, Informative)
Not really.
There is no 'safety mechanism' as such that stops it heating hands.
The coil can safely be energised with no load.
It won't get too hot, or anything, and it won't noticably heat your hand, or a duck, or anything non-metallic.
(well, it would heat graphite blocks and such, but that's cheating).
The reason for the device not turning on with no load is to prevent it heating up forks and other metallic implements that have been placed on the surface.
www.st.com/stonline/books/pdf/docs/12443.pdf
Re:Producing high voltages isn't going to work. (Score:3, Informative)
A Tesla coil works by a very high primary pulse of current and then it ringing in a LC tank at the same frequency the resonant secondary is. Most inductive cooktops have no tuning to match the resonant frequency of the secondary. Most Tesla coils work on higher resonant frequency than the cooktops due to the nature of the secondary.
One is a non resonant shorted turn and low impedance. The other is high Q and resonant over a very narrow frequency range. Outside of resonance, it is high impedance.
Re:make aluminum foil burn (Score:3, Informative)
user-side answer (w/ Greasemonkey) (Score:4, Informative)
http://userscripts.org/scripts/show/40582 [userscripts.org]
Here's a user-side answer in the form of a Greasemonkey script... /. could thereotically implement a bit of JS like that server-side (this works with a bunch of URL shorteners)
Fun with induction heaters (Score:1, Informative)
If you want to play around with induction heating but don't want to risk an expensive cooktop, there is a slick little open source heater here http://www.neon-john.com/Induction/Roy/Roy.htm. About the same power as a residential cooktop but without all those pesky protections and a lot cheaper to build. A company called http://www.fluxeon.com has kits and stuff for this project.