DIY induction heater

Thread Starter

Quentief

Joined Feb 13, 2020
3
Hi everyone,

I post this thread because I would like to make a little induction heater. I recovered an old pc power supply, I disassembled it and I would like like to reuse some of its component to build an induction heater.

I have already begun tp make some researches on the induction furnace working principle but I have some difficult to understand how a Royer oscillator is working and how its frequency is defined. Also, I would like to know if a such circuit can be powered directly on the 230 volt rectified.

Actually, my idea was to make an high frequency 230 volts signal and then reduce its voltage and increase its amperage through a step down transformer, before to power the working coil. 20200211_232834.jpg20200211_234039.jpg

According to the power supply data plate, the components can deal with the 230 volt and use 8 amps (so r.m.s. amperage 5.7 A). So in theory I suppose I could use them to build a 920W induction heater. What do you think about ?
 

oz93666

Joined Sep 7, 2010
736
I don't know much about this ...only that for the step down you cannot use a transformer with laminations (used for 50Hz) ... the eddy current loss would be too high , must have ferrite core.
 

dendad

Joined Feb 20, 2016
3,316
Those power supply capacitors are dead.
And I think you will need to use an isolation transformer if you are after help here as direct rectified mains projects are forbidden as they are really dangerous, especially for novices electronics folk.

We like to encourage people to be safe, and live long and prosper ;)
 

Alec_t

Joined Sep 17, 2013
10,902
Also, I would like to know if a such circuit can be powered directly on the 230 volt rectified.
Not unless you are trying for a Darwin Award.
The fan and the heatsink of that power supply might be worth rescuing for your project, but I wouldn't risk much else.
There are several online threads about Royer-based induction heaters. Be aware that most DIY constructions seem to cause a lot of problems.
 

Janis59

Joined Aug 21, 2017
1,057
RE: ""idea was to make an high frequency 230 volts signal and then reduce its voltage and increase its amperage through a step down transformer, before to power the working coil""

Noone is doing like that
1) electrocuting safety
2) for so microscopic power like 1 kW the Royer circuit works so well, that any other solutions have simply no place.
 

Thread Starter

Quentief

Joined Feb 13, 2020
3
Okay calm down everyone, this was just a question I just want to understand, I do not need any threat upon my life or Darwin Awards references :)

Furthermore, I am not an electronics beginner, I have already made some projects which were designed to use the 230 volts.

Concerning the project, if you are all saying that use the main voltage would be too dangerous, let's find another solution. Maybe I can use a step down transformer to have 24 volts to power the device. However, can I ask you how does a Royer oscillator work and how can I design it's components ?
 

Dodgydave

Joined Jun 22, 2012
8,807
Okay calm down everyone, this was just a question I just want to understand, I do not need any threat upon my life or Darwin Awards references :)

Furthermore, I am not an electronics beginner, I have already made some projects which were designed to use the 230 volts.

Concerning the project, if you are all saying that use the main voltage would be too dangerous, let's find another solution. Maybe I can use a step down transformer to have 24 volts to power the device. However, can I ask you how does a Royer oscillator work and how can I design it's components ?
Have a look here for Induction heating circuits...

http://danyk.cz/index_en.html
 

shortbus

Joined Sep 30, 2009
7,446
If you look at all of the threads here and on other electronics forums asking about this, and see the problems people have, and weigh them with the fact that you can get one that will work right out of the box so cheaply from Ebay, it's going to be up to you which way you go. I bought the one that was suggested in this link, https://www.spaco.org/Blacksmithing/ZVSInductionHeater/1000WattZVSInductionHeaterNotes.htm I can give you a link to Ebay if you want.

The guy in that link has bought and destroyed many of the ones sold on Ebay and other places, spent a lot of time and money to find out what works and which one to buy and how to make it work. I looked at doing this to make a "bolt buster" and following his guidelines I now have one. Like much of what is on the net today most of it is BS, but after spending much time and reading about these ZVS circuits he seems to be the guru of these, not just trying to sell you something or promoting his brand, but doing the hard work and spending the time and money to get to a working induction heater.
 

Thread Starter

Quentief

Joined Feb 13, 2020
3
Like I said, I only want to understand, to experiment. I would like to make a very little induction heater from scrap to experiment the phenomenon and the circuit working. I am not expecting to melt a lot of metal, this is just for the fun :)



And next, to go further, I think I will probably buy a induction heater, when I will able to understand how that works. Shortbus, if you have a link to buy affordable induction heater, I am more than interested :)



Thanks for the link Dodgydave, I have already read this article. The two first induction furnace versions have their work coil directly connected to the 230 volts, but the third version seems to have a transformer between the oscillator and the work coil. I am not able to read the Czech but I suppose it should be a step down transformer.



However I am not sure, is it a Royer oscillator? Apparently, a circuit called IR2153 is used to drive four IGBT transistors. That does not match with Royer oscillators I saw.
 

shortbus

Joined Sep 30, 2009
7,446
Shortbus, if you have a link to buy affordable induction heater, I am more than interested
Here you go - https://www.ebay.com/itm/1000W-ZVS-Low-Voltage-Induction-Heating-Board-Module-Flyback-Driver-Heater-DIY/221930754804?ssPageName=STRK:MEBIDX:IT&_trksid=p2057872.m2749.l2649 That ZVS also comes with a coil made from copper tube that has a fiberglass sleeve over it to keep the coil from shorting out. If you heat things for melting or forging you need to run water through the coil to keep it cool. The board is a two sided heavy copper board, most of the other ones sold on Ebay or elsewhere are light weight copper.

Just don't try, like many who look for answers, to use any of them with a switching power supply. No matter how many amps a SMPS claims it has it won't work as good as a linear power supply. I bought a Hammond 182S transformer for my build and a rectifier module from Antek all on Ebay. If I hadn't found a good deal on the 182S that was too cheap to pass up, I would have bought my transformer from Antek also. Antek products are good and well made.
 

Janis59

Joined Aug 21, 2017
1,057
Answer is yes, 12 Volts are the most widespread for garage systems intended to use the car accumulator to descrew some rusted-in screws, and high-frequency transformers (smps) are used to professional 20-40 kW devices. First 99,9999% are Royer self-oscillating systems, whilst second are always bridges with PLL system to adapt the tank (and as well the load too) thermal deviations. For classical Royer those under 1 kW devices is different only with better stability of biasing as the classical Royer may burn if not start to oscillate. This effect is widely described ar Google. Circuits are plethora, just hit the enter button.
Examples
http://kaizerpowerelectronics.dk/general-electronics/royer-induction-heater/
https://markobakula.wordpress.com/power-electronics/500w-royer-induction-heater/
https://yandex.ru/turbo?text=https://usamodelkina.ru/14682-prostoj-no-moschnyj-indukcionnyj-nagrevatel.html
 
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