Sciencemadness Discussion Board

Basic Induction Heater Safety?

3DTOPO - 15-4-2016 at 21:51


I just received my 15KW induction furnace today! A long-time dream come true!

I see a lot of work coils covered with something, like seen here:

What material is covering the work coil?

Is that to insulate the bare metal to prevent shocks? What happens if one makes direct contact with a bare copper work coil when operating?

Can anyone recommend or point me to general safety precautions? Anything else I should know?


3DTOPO - 15-4-2016 at 23:06

Apparently it is high-temp paint to avoid sparks if the work piece touches the work coil. I still wonder how safe it is bare though (not that I plan on touching it - just wonder if I should insulate it for safety).

Fulmen - 16-4-2016 at 01:54

I doubt it will be harmful to touch, the coil operates on low voltage/high current.

Aurium - 16-4-2016 at 08:22

Most induction heaters I'v seen used a LC circuit to oscillate the high-current around the coil.
To to this the LC circuit must also slosh around high voltages (say up to 800V).
It's a sine wave between voltage and current in the coil.
So I say don't touch it just to be sure. :P

3DTOPO - 16-4-2016 at 15:53

Yeah, crazy because I have seen a bunch of people touching the coil (either with a hand or a bare metal work piece). They claim mine is low voltage for an induction heater (think its like 400v). The energy running through the coil is RF though, not alternating current right?

Here are the results from my first run. Melted some mild steel and drill bits in minutes from a cold start!

Twospoons - 17-4-2016 at 14:25

RF and AC are the same thing, just different frequency. I'd say don't touch - the work coil could easily be several hundred volts above ground potential, depending on the circuit topology.

aga - 17-4-2016 at 14:38

Quote: Originally posted by 3DTOPO  
What material is covering the work coil?

Can anyone recommend or point me to general safety precautions? Anything else I should know?

The coil insulation is probably some sort of polymer : basically a non-conducting paint to prevent the coils being accidentally shorted out by some metal they're supposed to be melting.

General precautions would be to remove all metal, such as rings, watch, piercings, belt buckle - anything metal that you may be wearing.

Never touch the coil as it might be extremely hot if the coolant pump failed.

These things melt metal, so best not to wear any metal on any fleshy parts you want to keep intact.


Accidentally shorting out the coil will break it.

The Powers involved absolutely require the coil to emit the RF energy very efficiently.

If you short out the coil, a Vast amount of RF energy goes straight back into the electronics and instantly detroys them.

We all know what happens once the magic electronic smoke escapes.

[Edited on 17-4-2016 by aga]

Sulaiman - 17-4-2016 at 21:40

Obvious but I'll mention it anyway,
my brother-in-law leant over a hotplate in a restauraunt and was severely hurt by his pacemaker being 'cooked' by the induction heater hob
he was rushed to hospital and had to have a new pacemaker fitted.

So put up a BIG warning sign because if a 2 kW hotplate is hazardous,
your induction heater is lethal for users of a pacemaker (or other implants)

Photonic - 9-6-2016 at 19:23

The coils operate at a considerably low voltage. I suppose it is theoretically possible that if some internals failed and it was not a transformer coupled design that there could be hazardous voltages present but that is unlikely as passive components especially of the ceramic capacitor or inductor type rarely fail it will most often be semiconductor devices.

The frequency of operation is in the ~Khz range for larger objects to heat and can get up to higher frequencies for powders/smaller objects and the coils can generally be changed depending on the piece to be heated.

Like others pointed out don't stick your hand in there with jewelry on, or conductive items. You can throw a piece of high temp sleeving over the coils if you're worried about shorting it. They are cooled by water so they don't overheat so the coils themselves should not be nearly as hot as the piece you are trying to heat. An induction heater like this works kind of like a transformer. When you put in an object it acts as a short circuit on a transformer essentially supplying large amounts of current to the object by electromagnetic induction and induce joule heating through the resistance of the material.

These things are lots of fun, and I've built a couple myself. If you do anything with it come back and post pictures!