Induction heating

[williamhad]

how are you powering this....ive tried a car battery charger and it shorts out

[kynaniska83]

@williamhad

Im using a old laboratory power source (0-65V, 0-15A) in this clip. Maybe your impedance is too low for battery charger. Also you will need to filter (compensate) input voltage. IH is pretty hard load for PS.

Im using rectified mains in my latest heaters (approx 330 V DC) but I recommend you to use lower voltage due to electric shock risk (and much more advanced design).

[kynaniska83]

@williamhad

Do you use series resonant or parallel resonant circuit? If you arent precise in resonant freq (and in phase) with parallel circuit, your impedance is something like 0 Ohm and PS shorts... Lab PS is required for tuning the phase (and pulse width) before pushing more power to heater.

[yamum0433]

imma chargin mah lazer

[Dekoomer]

Geez when i 1st open the vid my mouth dropped it look like the freaking thing was gonna fire a laser! but no.. it was just heating an object

[kynaniska83]

@Dekoomer

That kind of stuff is under r&d. ;)

Ill let you know later...

[kuposrock]

i was waiting for it to fire a laser

[naxps]

Those would be the coolest car headlights in the world.

[wolvespage]

lol, agreed

[0273482300]

induction heating ?

how does that work?

[XmegaPresident]

LOW MENTALITY!!!!!

STUPID!!!!!

DUMBASS!!!!

Please pick one that best defines you "ellliotmotoX"

[uskmunder]

could i create a 1000hz sine wave, record it to my psp then get a low impendance car amplifier of the 1000 watt or more range then get a special coil like yours and be able to work?

[lazzer408]

No it wont.

[TehMG]

You need way more than that. I believe most induction heaters function at several hundred kHz.

Most are done with a MOSFET/IGBT switching circuit and an LCLR tank circuit or other variations. The whole becomes resonant at a frequency usually a few hundred kHz.

[TechnologyGod]

Tried it ended up burning up the transisters, only mine was going to be a tesla coil with almost no load on it. I only got 8000 volts out of it at less than 100 mA. Might have made a great HVPS for a klystron.

[kynaniska83]

@TechnologyGod

PLL is the answer for it. Fixed freq is too hazardous for transistors. It does work in this special application (with good oscillator circuit), but i recommend to use phase-locked setup for parallel-resonant circuit (i would use it also with serial-resonant in tesla coil).

BTW, my latest heater gives out several kilowatts and no problems with transistors has occured. After finishing interlock- & power adjustment circuitry, ill prolly share pcb:s and schematics.

[TheOnedeadguy]

@uskmunder That won't work plain and simple.

[kynaniska83]

This oven can reach 2150C and keeps its temperature very stable (I tested it 9 days in 1850C). It is now used in metal (like chromium and titanium) vaporizing in ion source at accelerator lab of University of Jyväskylä. Iv now produced both of those heavy ion beams with that oven.

Now im going to do one bad ass heater with H-bridge circuit... Ill let you know if it works. :D

[zimribbit]

Hi I am EV owner - really struggle in winter time. Heat = Lots of amps and reduced range.

Would this work off 12-48V and would it use alot of amps/power? Could I use it to keep me warm?

[kynaniska83]

Prolly it is much easier to use direct heating with interior heater... :)

[marcheseDS]

Use a personal heater under your coat. Heating only your body and not the car (air, structure etc...) it will drain a lot less energy from the batteries. To use only if you drive all alone of coarse...

[trailkeeper]

Do they make fused-quartz that way?

[dragonridley]

What were you heating?

[kynaniska83]

(empty) molybdenum crusible. Oven is nowadays used for metal evaporation/sublimation in ECR ion source for heavy ion beams. I have made for example titanium and chromium beams with it.

[BenHutchinson1]

Isn't this also how a sulfur lamp works? Sulfur vapor is heated inductively by a high frequency magnetic field?

[dudebot09]

yes, and no. im pretty sure sulfur lamps use microwaves (1gh-10ghz). from my knowledge, induction heaters usually run between 1kz and 300khz. it is close to the same concept, just completely different

[BenHutchinson1]

I know that a microwave oven works at 2.4ghz. And I know that if you put a metal in the microwave oven it is dangerous (presumably because it gets VERY hot) although I haven't tried it myself, so I'm not totally sure why. But if it is because the metal gets hot, then that is proof that induction heating CAN be done at microwave frequencies.

And just as a quick question, where is the frequency boundary between "radio waves" and "microwaves"? I've heard 300Mhz, 1ghz, and 2.4ghz. But which is tru?

[RyuDarragh]

Officially it's 300MHz. That's 1 meter wavelength and covers UHF to Millimeter wavelengths (like 1 THz). Beyond the THz range, it's Infrared. Oh, and the danger with a microwave oven and metal is that the metal acts as an antenna and causes electrical discharge, too, which adds to the high heat danger :P

[marcheseDS]

Usually around 1GHz but is a conventional matter; 300MHz is still in the TV broadcasting band if I remember well.

[frizspin175]

how do you make an induction heater?

[RyuDarragh]

You need an oscillator and an amplifier, like the kind used for home audio but at higher frequencies, with the power output you want to use and capable of feeding a *very* low impedance load. The oscillator feeds the power amplifier (sine waves work best), the amplified sine wave induces an oscillating magnetic field in the coil and *that* induces large currents in the conductive object to be heated. The resistance of the metallic object to electrical currents heats it up.

[kynaniska83]

A bit like that. Besides that kind of amps doesnt have good enough efficiency. That "amplifier" in IH is a bit like D-class amp, but works between high impedance and low impedance state, so it acts as a switch. In ZVS IH there is parallel resonant circuit. Other side is in DC voltage and other is pulled into ground through the switch. Frequency is bit over resonant freq of resonant circuit and pulse width is 10-25%.

Pretty simple idea, but requires lots of engineering for reliable operating.

[RyuDarragh]

True enough, Class D is more efficient, but I still form a sine wave at the coils resonant under load frequency (I like my neighbors and I have a 4KW Class D amp that can drive 0.5 Ohm loads at up to 40KHz.. still loads of smokeage potential so I let folks who actually *need* to do IH play with it :P).

[nighawaaaxx]

what does induction mean? i thought it meant like intake?

[m4d3ng]

Typically means to induce a rapidly changing magnetic field into an object causing it to heat up.

[weetsie]

SHOOP DA WHOOP

[kynaniska83]

360 -> 1850C

C-type thermocouple