Inductor heater resistance?

Hi,

I have an induction water heater.
Recently I checked its resistance using a multimeter.
But surprisingly I found it as zero.

I wonder why its not getting short circuited...


any idea?

Induction Cooktops | Home Appliances/Industrial Systems | TOSHIBA Semiconductor Company

---------- Post added at 14:22 ---------- Previous post was at 14:20 ----------

As by the name inductor heater, inductors have far lesser resistance than resistor. Inductor is more to the reactance

Induction heater usually do have a very low resistance (not zero). The AC current in a inductor is limited by "reactance" not resistance. An inductor is basically just a big coil of wire. Reactance is a property of inductors in an AC circuit which has a similar EFFECT to resistance (but is definatly NOT the same thing!)

Try googling "inductors" or "reactance" or "back EMF" or reading a Alectrical Apprentice text book. The later will explain the whole theory and you only need a bit of high school math (algebra and triganometry).

If you simply connect a big inductor and switch it on, it will initially behave like ther is a dead short - you get a HUGE "in rush" current for a fraction of a second. Induction circuits like heaters, induction stove tops, large electric motors etc usually have special control gear that limits this inrush or special circuit protection that can handle it.

If you put DC through an inductor and then switch it off, you get a BIG voltage with the reverse polarity. This is how the coil in your car ignition system produces nice big sparks at your spark plugs.

Induction is measured in "Henry's" (I'm not joking!). You need specalised equipment to measure it - a standard multimeter won't do the trick. You can calculate the reactance of the circuit from this and that will tell you what current to expect.

Playing with big inductors and AC mains voltages is REALLY not a good idea without AT LEAST some basic knowledge. Please, please go and do some research before you hurt yourself!