Good job, I enjoyed the layout, the specs on components, and the very accurate description of the solitary drawback, and the immediate fix, using two cores, and 12 gauge wire. The "scope" shows the exact impact of fixing the core saturation issue. Quite a professional job, I have a 300 amp tig welder in my shop without running water, and found two water cooled motorcycle radiators, Honda, if I remember right, am running a "vibrator pump" circulating water when the welder is on, and it's worked a decade with no problems. I run ten or twenty percent radiator fluid, and have a glass "ball" quart canning jar, with a hole drilled in the bottom and near the top on the side for copper tube epoxied in, for a visual flow indicator and fluid quality view. I leave about half the jar air, for expansion, but haven't ever gotten the water more than warm. Thanks for a great video, good sound electronics, and sound engineering.
I doubt DIY coils are really worth it. Given that you need to probably buy excessive amount of 12AWG magnet wire as in whole spool, + the cores + the extra work, it's probably better to buy off the shelf inductors, for some people it might end up same as the parts cost, and you end up with superior inductors which will have lower losses. You will be spending 25-35 euro for the parts, meanwhile you can buy two high power inductors for around 15 each. Also if you end up buying different cores, you risk getting issues and having to buy different cores and wasting more time and wire.
I used to work for Vulcan Forge in San Jose we used to forge 2 1/2 inch wrenches for Stanley and Proto in closed die forgings they forged at temperatures 2,300° f , and the induction heaters we used to use were also tuned to the coil, by connections made on the capacitor Bank, and every coil had deionized water going through it, and the billets were fed through it also had two rails liquid-cooled rails going down through the center of the coil, they were all made a stainless steel tubing. The forge had coils that can handle anywhere from a half inch material all the way up to 3 in Plus
You must have triggered some Kens on another of your videos or else 79 people accidentally pressed the thumbs down button. Seriously, very nice board and very thoughtful design and follow-up to clean your sine. And I am grateful for the doubled toroid trick. When I lived in Houston there was a serious electronics surplus and salvage shop with buckets of fist sized toroids on down with maybe the largest being $10 to $15. I always swore to come back and raid their stock when I started prototyping induction furnaces but sadly I have moved too far away now and they don't do online sales. This was the type of place that used to have salvaged ships radars and teletype machines and copper vapor lasers and on and on. I could spend half a day drooling in the aisles.
And if you need anything just let me know I can just grab it for you when I go I only live out past Katy Mills so it's like a 45 min to 8 hours trip depending on how dumb i10 or West Park are being
around the 21 minute mark you state the internal resistance of the metal decreases with heat - it is actually increasing in resistance. This can be explained by faradays law of induction. because a constant Bflux is changing, a constant EMF is applied to the metal causing eddy currents. and P = V^2/R. which tells us as resistance increases, P decreases.
@@ichbineltyb3814 That's right. It's not the electrical resistance that's at issue here. He's heating a FERROUS metal. That means it's highly magnetic and the main heating effect is not from eddy currents but the continuous, rapid reversing of the magnetic field is 'jiggling' the magnetic domains of the metal, causing friction and hence heat. BUT as the metal heats up and passes the Curie point, the magnetic response suddenly drops and that strong heating effect ceases.
Thanks for the video. Nice work! Just a note on why the temperature of the iron stops climbing. Resistance actually increases with heat but that is not the reason. At these power levels and frequencies the heating depends mostly on the magnetic properties of the workpiece. That is why a non magnetic workpiece does not heat as well. The magnetic workpiece actually becomes non magnetic when it reaches the curie point or curie temperature and does not react with the coil as strongly. For steel this is almost 1400 deg. F. You can mess around with a propane torch, a nail, and a magnet for a demonstration. Nickel and its alloys can do this at lower temperatures. Some magnetic coins are fun to play with (Canadian one dollar loonie).
Can't believe he said resistance decreases with temperature (never heard of superconductors buddy ?). At melting temp of iron its resistance has increased by 100%.
Eddy current losses versus hysteresis losses. Hysteresis losses are typically the bulk of your heating effectiveness with these frequencies and these metals. For metals that don't benefit from hysteresis losses (aka "nonmagnetic"), you generally need higher switching frequencies as well. Take all of this with a grain of salt and confirm yourself, but these are my experiences working in a place that designed these.
Worked for Sundstrand Aerospace in packaging Wild frequency input from a generator mounted to a jet engine gearbox and rectifies it and converts it to 400Hz 3 phase. One in production is a 30KW unit. So I was responsible for coming up with cooling and packaging. One suggestion is to attach that copper tubing to the circuit board for the straight buses for the capacitor bank. Attaching the inductor and semiconductors to the back side with the tubing will make it easier to use the liquid to cool the circuit. Just a thought.
You haven't seen hot until you've seen a 400 kW power supply on a 5' dia. chiller-cooled coil, heating a solid graphite billet surrounded by a few hundred pounds of powdered graphite. It was white hot for several hours and took all next day to cool. We were making the first woven carbon-carbon composite rocket nozzles and nose cones at SAI (before it was SAIC) for the Air Farce and NASA. Our technique was used to make the Galileo Jupiter probe's heat shield.
I am wondering if the metal would get hotter if the coils were wound in a tighter circle. I believe the metal needs to get at least yellow hot for proper forging or perhaps other uses. I am thinking a nice project would be for you to make a second coil to swap out with this one for times when you want to heat up something smaller and make it hotter. Not criticizing what you did in anyway. You are a great teacher and demonstrator on here. love your channel.
I used to work at a forging company these induction heaters and it would just get to brilliant yellow you'd almost need sunglasses to look at it and we used to forge at 2,300°, if the Hammerman get it too hot when the Closed Dies hit the metal it would explode and shoot sparks everywhere just like a flint on a lighter
Brilliant. I will be trying to make 3 heaters with elongated pancake coils to achieve 9 kw heating on top and sides. Leaving the bottom open to get a workpiece in the contraption freely and prevent contamination of the coils by falling debris. Thanks again.
I was going to recommend just bending the whole work coil to match the trace shape and directly soldering components to it through the PCB, but your idea would be a lot easier...
With Rds on for those IRFP4668 mosfets being in the range of 0.008 to 0.010 ohms, I think you must have high switching losses contributing to that 67.3 degrees mosfet case temperature measured at 23:10 in the video. If it were me I'd experiment with lower values for R2 and R4. In fact, given the specs. on those mosfets I wonder if it is even necessary to use four of them for a 3 kw throughput? It seems that with proper gate drive and cooling, two should be able to safely handle it.
Very interesting project and you are obviously very skilled in electronics. I was drawn to your video by the possibility of using an induction heater for heating some smaller projects in my black smithing work. Firing up my gas forge to do small work is not very efficient. While very informative I want to mention that the steel was no where near a forging temperature. The steel needs to be between 1200- 1300 degrees centigrade to be effectively forged. That is an incandescing yellow heat when viewed in shade. I am confident that you, given your expertise would be able to design an induction circuit to meet the temperature criteria. Again a great video and information thank you for sharing it.
Problem with the circuit is probably the Mosfets IRFP4668. They have a high gate capacity and tend to swing at the gate at the smallest cicuit induction in the gate path. Thus they dont switch fast and exact enough and build up a lot of heat quickly. Did you measure the gate signal with an oscilloscope? Would be interesting to see. They have to advantage of high voltage switching at high amperage, but they are hard to control in this self oscillating circuit.
@@papvendel7490 If you bought cheap at ebay, they were probably fake Mosfets - they burn easily. Maybe there was a problem with the gate signal, a ringing, and not properly switching. You have to measure the gate signal.
The weak link with these circuits are the resonant capacitors. So many required to obtain the capacitive value and series current capability. Pity those old high power valve transmitter caps are not more common. Capacitors out of the high frequency TiG welders are made by Miller and can take a lot of current. What is really needed are water cooled capacitors. Must try making some.
If i understood the function of this device correctly, the resonance is used to create a high frequency AC to drive the work coil? One could use a microcontroller instead to run the semiconductors at the desired frequency like in an switchmode powersupply and get rid of the coils and capacitors alltogether right? Perhaps only one big cap to smoothen the draw on the supply.
Thank you, this is fantastic... I am assuming that it heats up to 600-700 deg celcius? If one was to make the bus bar, would you solder it to the traces or just have it attached at correct points?
I really love this video and want to try building this. I really want to build this in very small coil I want heat a very small pipe on my brass instrument can you advise how I can do this without overheating the pipe just keeping it warm ?
Great stuff... Any idea how much all that would cost approximately and it's it scalable I.E. 10KW, 20KW, 30KW, etc. How about a more in depth explanation of the circuit say breaking it down into sub circuits like how is the Sine wave generated. Is there a PDF to accompany the build if one should try building it for themselves.
AWESOME I.H. and P.S. !!!!!!!!!!!!!!!!!!! I was going to comment on the capacitor diagonal connection, but you mentioned it as I was watching further. One thing that I have found done somewhat inadvertently in helical work-coils is in how many turns actually produce flux interaction with a work piece. If you get the opportunity, could you take the coil and connect a thin wire across the terminal leads near the coil, and then dip that 'closed loop' into a soap-bubble bath, then pull it out and just count how many 'closed' circular surfaces appear through the coil's center...these are the ones that contribute to heating / flux-coupling. I have found that it can often be less than it would seem by counting 'turns' by sight. Fractional loops at the ends can be very misleading. THANKS MUCH... Please let me know if / when you do it. I have seen cases when the true number of 'useful / legit' turns has been as many as two less than some large I.H.'s makers claim, even though it may look so. --dALe
The 12 ga magnet wire I obtained was STIFF. I had to clamp my toroid stack in a soft jawed vice while winding it, and it still looked really sloppy. Schematix made it look so easy.... Oh well, hopefully it will still get the job done.
Are you worried at all about shorting the induction coil with your workpiece? I've notice some other builds where they use a fiberglass looming material to cover the coil windings.
A variety of coil sizes matched more closely to the size of the object being heated will greatly increase the temperature of the object Once worked for a company turning out induction heated rivets and such and our coils were not much more than .25" clearance or less around the part...also our coils had water circulating them for cooling
Johnny, if you are still there...? Could you please elaborate a bit more on what you mean by "coil sizes matched more closely to the size of the object" ? How much margin between the outer edge of an object (assuming it's closely centered in the coil) and the inner edge of the coil would you recommend? Thanks...
@@sempertard These devices operated at extremely high voltage and the coils were actually copper tubing, round or square, and shaped for the area of the product that needs hardening with water flowing through the tubes constantly. For instance, one item we did a lot of was a rivet slightly larger than a human thumb and the part would go from ice cold steel to bright red hot in a matter of seconds and then quickly removed and dropped into the quench tank edit: another critical component was the requirement to never ever let the part touch the coil and for that we had heat resistant cloth and a paper-like substance I would say maybe keep experimenting with coil sizes and if more or less turns in a coil makes a difference and if you want to have a smaller gap then make sure to have something non-conductive between the coil and the part being heated edit-edit: the gap shown at 21:40 is perfect and to make it even more perfect could be to make a dedicated crucible coil and turn the lower coils such that they maintain that same perfect gap all the way down, making your perfect crucible coil even more perfecter :-) Also if you can shed enough heat from the copper tube with water you might see higher temps on the crucible EDIT, EDIT, EDIT: just came back from your channel looking for a video about how the coil worked after hooking up to water and if you've melted anything in the crucible...so, did it work ??
Using coaxial cable braid is the best for reenforcing copper pcb tracks. Sweat it onto the tracks with a liberal amount of solder. Flexible and easy to work with.
hi, how about make it the siplest one? i mean not using the additional power supply, but using directly from the power outlet, and supposed to be about 310vdc, please advise me wich needs to be modified? thanks. cheers.
Just wondering if you had a target resonance for the output? We use our induction heaters for copper brazing, but I can't recall the exact kHz value that works best for non ferrous metals. Would be good to have a small mobile unit like this for the smaller connections of leads in the series and parallel circuits. Great build! 👍
For my application I was targeting what would be referred to as 'medium-frequency' the end result was around 39~40kHz. For ferrous metal, my understanding is mid~low frequency yields quicker heat time due to the 'skin effect' of higher frequencies
@@Schematix Does this include the graphite cruicible? I have not found any info on what frequency they heat best. Ive got a 200ml size and made a 135mm diameter coil for it. 11 turns, about 5 meters, I will need to shorten it after some testing. Thanks for the video.
great vid. how hot the water pump into the coil would get. Im looking to build this to heat up water that would be spray on to dry ice to create a low laid fog. Can you spread the turns of the coil to cover a larger area and get a wider hot spot. ?
I started my own induction heater project, so far you are way ahead of my progress but your project is looking exacly as I want my project to look, amazing, cant wait for the water cooling system, that is goint to be very interesting
A couple of questions. 1-Is there a frequency that is chosen to heat steel? 2-I want to build this heater to temper knife blades. How could I modify the coil? Because it has a dimension of 300 mm x 3 mm thick.
I am a paramedic and have very little knowledge about scratch building any electronics. But I must give credit when due, you are very neat and tidy when you build sir. I wonder if the engineers who built the Apollo rocket systems had to be just as creative, neat, and tidy?
Greetings, is it possible to use a MOSFET inverter welding machine with an output of 55 to 60 volts DC and a current of 100 amps to start a 3 kW induction furnace instead of a power source?
Ellerinize sağlık usta, mkp kondansatör yerine mkph kullanırsanız aynı görevi görür mü. Metal oksit direnç yerine seramik direnç olsa ne gibi etkenler oluşur.
if you could drive a transformer core at them frequencies couldnt you make the core from an old microwave transformer? or even use the ballast coil from a treadmill? if it has to be fereite (iron/ceramic) you could make one using. 1. flyback transformer core from old tvs (they usually are split). 2. tv horizontal deflection yoke cores they are usually split and can be hand wound. all fereite cores are made of iron and ceramic and are fragile and can break very easy. the iron makes the magnetics work and the ceramic gives the shape and maybe allows the cores to be much more effiecent operation.
Mr. Schematix , I watched your videos on induction heating, and decided to build your version of the 3000 watt induction heater. I ordered your circuit boards of course you get five circuit boards (no problem) then I ordered all the other parts. I followed your video to the best of my ability. WOW this thing works great ! Now to my problem, I got extra parts and extra circuit boards so I built another one ( now I have two). second one works just as good as first. WHAT IF I parallel the two circuit boards ? Hook up positive and negative inputs to same power supply and then hook up both outputs to ONE coil. Will I now have 6000 watts of induction heater or a bunch of sparks and smoke? I have two communication power supply in parallel with 220volt input so about 100amps available can this work or should I film it when I first hook it up?
Alternatively you can fill the tube with water and freeze it I found it this works better than using sand. Have made heat exchanger coils for condensers for large distillation purposes
So, on the subject of coils: let's assume we want to use it for forging knives. Usually this means we start off from material that's relatively flat, having a more or less rectangular cross-section. Would it be helpful to have the coils conform to this shape rather than having them be round? Second question: since it's not a good idea to touch the coils while in operation, and since electricity can travel from the coil to your body through the tongs when the work piece touches the coil, how would you to about protecting the user from accidental contact? Would pottery enamel hold up, if we paint the coil in this? Will it adhere to the copper in the first place? Will it impact performance? Are there better options?
Since you are using lead tin solder which is kinda regular solder. How about using a high quality solder that that has 6 percent silver. That would make the conductivity a lot better. What do you think fella ???
@@Schematix What else would you do to lower the electrical amperage of the unit Sir ??? Different or more capacitors, transistors. Heavier gauge wiring. WHAT Thanks
Another first class video. I will use this idea to make an instant water heater. Will pass a 3/4 inch galvanised steel pipe through the coil without touching the copper. Then push water through and will experiment with water flow . Please what is the frequency you are using. I thank you again for sharing. Firstclass project.
Since you used only one wire twelve gauge wrapping the inductor ring. Would using two wires make the efficiency go higher since resistance will be lower ???
Can you share any sources for learning about who these are designed and built? I would like to know how I can design and build my own for a specific size and power use-case.
hi; i have checked the cost of the pcb in JLC and they want close to $200 for 5 boards, I only need 1, max 2, do you have a reference number for your pcb , so I can get a more accurate quotation? of better still , do you sell the PCB your self? kind regards Mariano
I'm not a julous type but I'm jealous of your tools and knowledge and how did you know it was the coil making the wave wrong and not something else these induction heaters look cool what happens when you only pass water thought it does it heat the water?
Good job, I enjoyed the layout, the specs on components, and the very accurate description of the solitary drawback, and the immediate fix, using two cores, and 12 gauge wire. The "scope" shows the exact impact of fixing the core saturation issue. Quite a professional job, I have a 300 amp tig welder in my shop without running water, and found two water cooled motorcycle radiators, Honda, if I remember right, am running a "vibrator pump" circulating water when the welder is on, and it's worked a decade with no problems. I run ten or twenty percent radiator fluid, and have a glass "ball" quart canning jar, with a hole drilled in the bottom and near the top on the side for copper tube epoxied in, for a visual flow indicator and fluid quality view. I leave about half the jar air, for expansion, but haven't ever gotten the water more than warm. Thanks for a great video, good sound electronics, and sound engineering.
I doubt DIY coils are really worth it.
Given that you need to probably buy excessive amount of 12AWG magnet wire as in whole spool, + the cores + the extra work, it's probably better to buy off the shelf inductors, for some people it might end up same as the parts cost, and you end up with superior inductors which will have lower losses.
You will be spending 25-35 euro for the parts, meanwhile you can buy two high power inductors for around 15 each.
Also if you end up buying different cores, you risk getting issues and having to buy different cores and wasting more time and wire.
I used to work for Vulcan Forge in San Jose we used to forge 2 1/2 inch wrenches for Stanley and Proto in closed die forgings they forged at temperatures 2,300° f , and the induction heaters we used to use were also tuned to the coil, by connections made on the capacitor Bank, and every coil had deionized water going through it, and the billets were fed through it also had two rails liquid-cooled rails going down through the center of the coil, they were all made a stainless steel tubing. The forge had coils that can handle anywhere from a half inch material all the way up to 3 in Plus
What were the advantages of tuning it?
Did they tell you what happens if you don't tune it?
You must have triggered some Kens on another of your videos or else 79 people accidentally pressed the thumbs down button. Seriously, very nice board and very thoughtful design and follow-up to clean your sine. And I am grateful for the doubled toroid trick. When I lived in Houston there was a serious electronics surplus and salvage shop with buckets of fist sized toroids on down with maybe the largest being $10 to $15. I always swore to come back and raid their stock when I started prototyping induction furnaces but sadly I have moved too far away now and they don't do online sales. This was the type of place that used to have salvaged ships radars and teletype machines and copper vapor lasers and on and on. I could spend half a day drooling in the aisles.
I love EPO too moved to out of town but still get over their when I can
And if you need anything just let me know I can just grab it for you when I go I only live out past Katy Mills so it's like a 45 min to 8 hours trip depending on how dumb i10 or West Park are being
Great to hear you say 'Soldering' as opposed to 'Soddering' ! Cheers mate; keep up the great work...
Nothing wrong with regional dialects having different pronunciations.
Loved this and am going to do it. On a side note, loved the fly checking out your work. It always adds to the video to have an assistant
Awesome! Thank you!
funniest ad I've seen in a long while! You rock.
around the 21 minute mark you state the internal resistance of the metal decreases with heat - it is actually increasing in resistance.
This can be explained by faradays law of induction. because a constant Bflux is changing, a constant EMF is applied to the metal causing eddy currents. and P = V^2/R. which tells us as resistance increases, P decreases.
AFAIK it has to do with curie temperature
@@ichbineltyb3814 That's right. It's not the electrical resistance that's at issue here. He's heating a FERROUS metal. That means it's highly magnetic and the main heating effect is not from eddy currents but the continuous, rapid reversing of the magnetic field is 'jiggling' the magnetic domains of the metal, causing friction and hence heat. BUT as the metal heats up and passes the Curie point, the magnetic response suddenly drops and that strong heating effect ceases.
Correct i think he just got mixxed up
I'm sure it just a slip of the tongue.
Thanks for the video. Nice work! Just a note on why the temperature of the iron stops climbing. Resistance actually increases with heat but that is not the reason. At these power levels and frequencies the heating depends mostly on the magnetic properties of the workpiece. That is why a non magnetic workpiece does not heat as well. The magnetic workpiece actually becomes non magnetic when it reaches the curie point or curie temperature and does not react with the coil as strongly. For steel this is almost 1400 deg. F. You can mess around with a propane torch, a nail, and a magnet for a demonstration. Nickel and its alloys can do this at lower temperatures. Some magnetic coins are fun to play with (Canadian one dollar loonie).
Can't believe he said resistance decreases with temperature (never heard of superconductors buddy ?). At melting temp of iron its resistance has increased by 100%.
Eddy current losses versus hysteresis losses. Hysteresis losses are typically the bulk of your heating effectiveness with these frequencies and these metals. For metals that don't benefit from hysteresis losses (aka "nonmagnetic"), you generally need higher switching frequencies as well. Take all of this with a grain of salt and confirm yourself, but these are my experiences working in a place that designed these.
You do good work. People could learn a lot about doing things well regardless of the projects themselves. Thank you for the effort.
Much better with the music by not making it too loud. Great video by the way!
Given the equilibrium you mention at #21:05, how do induction furnaces melt iron? Building an induction furnace is what I'd like to do.
Worked for Sundstrand Aerospace in packaging Wild frequency input from a generator mounted to a jet engine gearbox and rectifies it and converts it to 400Hz 3 phase. One in production is a 30KW unit. So I was responsible for coming up with cooling and packaging. One suggestion is to attach that copper tubing to the circuit board for the straight buses for the capacitor bank. Attaching the inductor and semiconductors to the back side with the tubing will make it easier to use the liquid to cool the circuit. Just a thought.
for larger inductor rings check out ham radio supply sources, large rings are used with lower frequency "HF' antennas.
Finally an Induction heater build in a language that I can understand
You haven't seen hot until you've seen a 400 kW power supply on a 5' dia. chiller-cooled coil, heating a solid graphite billet surrounded by a few hundred pounds of powdered graphite. It was white hot for several hours and took all next day to cool. We were making the first woven carbon-carbon composite rocket nozzles and nose cones at SAI (before it was SAIC) for the Air Farce and NASA. Our technique was used to make the Galileo Jupiter probe's heat shield.
Actually, I've seen hot. In fact, I see hot every day. So have you, and everyone else you or I know. It hangs in the sky. 😉
This sounds awesome. Would love to know more about how this was done.
Please talk to TH-camr smarter every day.
I am wondering if the metal would get hotter if the coils were wound in a tighter circle. I believe the metal needs to get at least yellow hot for proper forging or perhaps other uses. I am thinking a nice project would be for you to make a second coil to swap out with this one for times when you want to heat up something smaller and make it hotter. Not criticizing what you did in anyway. You are a great teacher and demonstrator on here. love your channel.
He has already said for best performance to match coil with work piece. This coil was designed to match his crucible for melting metal.
@@mevk1 That crucible should be able to melt some serious aluminum.
I used to work at a forging company these induction heaters and it would just get to brilliant yellow you'd almost need sunglasses to look at it and we used to forge at 2,300°, if the Hammerman get it too hot when the Closed Dies hit the metal it would explode and shoot sparks everywhere just like a flint on a lighter
LOL - when you pulled out the 2.0 model I audibly cheered I was so happy to see that! This is great, thank you for this video.
Brilliant. I will be trying to make 3 heaters with elongated pancake coils to achieve 9 kw heating on top and sides. Leaving the bottom open to get a workpiece in the contraption freely and prevent contamination of the coils by falling debris. Thanks again.
Can you tell me how people melt metal using induction heating ??? Look forward to see more of your creation.
That board layout is absolutely phallic
if you use copper brake line to reinforce the traces. you could also use the reinforcemet for watercooling the PCB. possibly.
I was going to recommend just bending the whole work coil to match the trace shape and directly soldering components to it through the PCB, but your idea would be a lot easier...
With Rds on for those IRFP4668 mosfets being in the range of 0.008 to 0.010 ohms, I think you must have high switching losses contributing to that 67.3 degrees mosfet case temperature measured at 23:10 in the video. If it were me I'd experiment with lower values for R2 and R4. In fact, given the specs. on those mosfets I wonder if it is even necessary to use four of them for a 3 kw throughput? It seems that with proper gate drive and cooling, two should be able to safely handle it.
Very interesting project and you are obviously very skilled in electronics. I was drawn to your video by the possibility of using an induction heater for heating some smaller projects in my black smithing work. Firing up my gas forge to do small work is not very efficient. While very informative I want to mention that the steel was no where near a forging temperature. The steel needs to be between 1200- 1300 degrees centigrade to be effectively forged. That is an incandescing yellow heat when viewed in shade. I am confident that you, given your expertise would be able to design an induction circuit to meet the temperature criteria. Again a great video and information thank you for sharing it.
another tip - if you own one, pre-heat the pcb and copper wire with a heatgun which helps out when soldering with a undersized iron
Problem with the circuit is probably the Mosfets IRFP4668. They have a high gate capacity and tend to swing at the gate at the smallest cicuit induction in the gate path. Thus they dont switch fast and exact enough and build up a lot of heat quickly. Did you measure the gate signal with an oscilloscope? Would be interesting to see. They have to advantage of high voltage switching at high amperage, but they are hard to control in this self oscillating circuit.
@@papvendel7490 If you bought cheap at ebay, they were probably fake Mosfets - they burn easily. Maybe there was a problem with the gate signal, a ringing, and not properly switching. You have to measure the gate signal.
The weak link with these circuits are the resonant capacitors. So many required to obtain the capacitive value and series current capability. Pity those old high power valve transmitter caps are not more common. Capacitors out of the high frequency TiG welders are made by Miller and can take a lot of current. What is really needed are water cooled capacitors. Must try making some.
If i understood the function of this device correctly, the resonance is used to create a high frequency AC to drive the work coil? One could use a microcontroller instead to run the semiconductors at the desired frequency like in an switchmode powersupply and get rid of the coils and capacitors alltogether right? Perhaps only one big cap to smoothen the draw on the supply.
Thank you, this is fantastic... I am assuming that it heats up to 600-700 deg celcius?
If one was to make the bus bar, would you solder it to the traces or just have it attached at correct points?
I really love this video and want to try building this. I really want to build this in very small coil I want heat a very small pipe on my brass instrument can you advise how I can do this without overheating the pipe just keeping it warm ?
Great stuff... Any idea how much all that would cost approximately and it's it scalable I.E. 10KW, 20KW, 30KW, etc.
How about a more in depth explanation of the circuit say breaking it down into sub circuits like how is the Sine wave generated.
Is there a PDF to accompany the build if one should try building it for themselves.
AWESOME I.H. and P.S. !!!!!!!!!!!!!!!!!!!
I was going to comment on the capacitor diagonal connection, but you mentioned it as I was watching further.
One thing that I have found done somewhat inadvertently in helical work-coils is in how many turns actually produce flux interaction with a work piece.
If you get the opportunity, could you take the coil and connect a thin wire across the terminal leads near the coil, and then dip that 'closed loop' into a soap-bubble bath, then pull it out and just count how many 'closed' circular surfaces appear through the coil's center...these are the ones that contribute to heating / flux-coupling. I have found that it can often be less than it would seem by counting 'turns' by sight. Fractional loops at the ends can be very misleading.
THANKS MUCH...
Please let me know if / when you do it. I have seen cases when the true number of 'useful / legit' turns has been as many as two less than some large I.H.'s makers claim, even though it may look so.
--dALe
The 12 ga magnet wire I obtained was STIFF. I had to clamp my toroid stack in a soft jawed vice while winding it, and it still looked really sloppy. Schematix made it look so easy.... Oh well, hopefully it will still get the job done.
Are you worried at all about shorting the induction coil with your workpiece? I've notice some other builds where they use a fiberglass looming material to cover the coil windings.
A variety of coil sizes matched more closely to the size of the object being heated will greatly increase the temperature of the object
Once worked for a company turning out induction heated rivets and such and our coils were not much more than .25" clearance or less around the part...also our coils had water circulating them for cooling
Johnny, if you are still there...? Could you please elaborate a bit more on what you mean by "coil sizes matched more closely to the size of the object" ? How much margin between the outer edge of an object (assuming it's closely centered in the coil) and the inner edge of the coil would you recommend? Thanks...
@@sempertard
These devices operated at extremely high voltage and the coils were actually copper tubing, round or square, and shaped for the area of the product that needs hardening with water flowing through the tubes constantly. For instance, one item we did a lot of was a rivet slightly larger than a human thumb and the part would go from ice cold steel to bright red hot in a matter of seconds and then quickly removed and dropped into the quench tank
edit: another critical component was the requirement to never ever let the part touch the coil and for that we had heat resistant cloth and a paper-like substance
I would say maybe keep experimenting with coil sizes and if more or less turns in a coil makes a difference and if you want to have a smaller gap then make sure to have something non-conductive between the coil and the part being heated
edit-edit: the gap shown at 21:40 is perfect and to make it even more perfect could be to make a dedicated crucible coil and turn the lower coils such that they maintain that same perfect gap all the way down, making your perfect crucible coil even more perfecter :-)
Also if you can shed enough heat from the copper tube with water you might see higher temps on the crucible
EDIT, EDIT, EDIT: just came back from your channel looking for a video about how the coil worked after hooking up to water and if you've melted anything in the crucible...so, did it work ??
Great job.😃i too try to find ways to lower costs for various electronic parts. things get very expensive.
Can you do a smaller build of this for those of us who uses an induction heater in place of a butane torch for our vaporizers for weed?
Using coaxial cable braid is the best for reenforcing copper pcb tracks. Sweat it onto the tracks with a liberal amount of solder. Flexible and easy to work with.
good circuit I would like to know if this circuit could be used as a magnetic induction cooker or not?
hi, how about make it the siplest one? i mean not using the additional power supply, but using directly from the power outlet, and supposed to be about 310vdc, please advise me wich needs to be modified? thanks. cheers.
thank you for the video. Can you please answer: what does the frequency of the inductor depend on? how to increase it from 40-50khz to 90?
I'm afraid I know nothing about electrical things, but I sure would like to have something like that to harden items I machine. I'll be watching!
Ji
Is there anyway you can modify the board to give a center tapped output please?
Just wondering if you had a target resonance for the output? We use our induction heaters for copper brazing, but I can't recall the exact kHz value that works best for non ferrous metals. Would be good to have a small mobile unit like this for the smaller connections of leads in the series and parallel circuits. Great build! 👍
For my application I was targeting what would be referred to as 'medium-frequency' the end result was around 39~40kHz. For ferrous metal, my understanding is mid~low frequency yields quicker heat time due to the 'skin effect' of higher frequencies
@@Schematix Thanks! Yes I assumed you must of had a specific inductance level to feed the resonance tank based upon your toroid windings. Nice work.
@@Schematix Does this include the graphite cruicible? I have not found any info on what frequency they heat best. Ive got a 200ml size and made a 135mm diameter coil for it. 11 turns, about 5 meters, I will need to shorten it after some testing.
Thanks for the video.
Esde projeto pra usar em brasagem de tubos de cobre seria importante pois e portátil me favoreceria muito
great vid. how hot the water pump into the coil would get. Im looking to build this to heat up water that would be spray on to dry ice to create a low laid fog. Can you spread the turns of the coil to cover a larger area and get a wider hot spot. ?
I started my own induction heater project, so far you are way ahead of my progress but your project is looking exacly as I want my project to look, amazing, cant wait for the water cooling system, that is goint to be very interesting
You can do it!
I am Nasuh Jaber
What was the temperature it got up to when making the metal red? What is the highest temperature it can do?
I want to know if its possible to make a solar powered, to charge a battery to heat up the induction forge?
Where you add copper to tracks could the actual tracks be increased to say an inch wide. There seems to be plenty of board to use.
A couple of questions.
1-Is there a frequency that is chosen to heat steel?
2-I want to build this heater to temper knife blades. How could I modify the coil? Because it has a dimension of 300 mm x 3 mm thick.
I would like to know what is the frequency and the maximum magnetic field in the coil.
Thanks.
I am a paramedic and have very little knowledge about scratch building any electronics. But I must give credit when due, you are very neat and tidy when you build sir. I wonder if the engineers who built the Apollo rocket systems had to be just as creative, neat, and tidy?
What is the power efficiency of this heater ? Is it possible to use it to make induction cookers by flattening the coil?
Can you tell me what I need to modify to make the circuit 7kw?
Does it work for melting gold in this case as well?
Thanks for the free Circuit Schematic. 😊😊
Hello sir you did a great work.please can you buy welding machine schematics from 120amp to 200amps
So iron and steel can be heated with an induction heater. What other metal's can be excited ? Can sulfate forms of various metal be induced with heat?
Greetings, is it possible to use a MOSFET inverter welding machine with an output of 55 to 60 volts DC and a current of 100 amps to start a 3 kW induction furnace instead of a power source?
Does the cooling water going in/out of the coil have a voltage on it?
I’d imagine it would be live?
Hi sire,
Can you actually melt iron with that? to cast it?
what about designing soft start for that royer oscillator? that beast create massive inrush!
I like those clip-on TO-220 heat sinks.
Ellerinize sağlık usta, mkp kondansatör yerine mkph kullanırsanız aynı görevi görür mü. Metal oksit direnç yerine seramik direnç olsa ne gibi etkenler oluşur.
Very impressive. Thanks for posting.
I would really like to see a video of you using the crucible! What a fantastic idea!!!
if you could drive a transformer core at them frequencies couldnt you make the core from an old microwave transformer?
or even use the ballast coil from a treadmill?
if it has to be fereite (iron/ceramic) you could make one using.
1. flyback transformer core from old tvs (they usually are split).
2. tv horizontal deflection yoke cores they are usually split and can be hand wound.
all fereite cores are made of iron and ceramic and are fragile and can break very easy.
the iron makes the magnetics work and the ceramic gives the shape and maybe allows the cores to be much more effiecent operation.
I would like to purchase two of your three KW induction heater pcbs. Will you sell two of the boards. Thank you Bart
Omg 😲this is amazing! 👏 I wish I had the tools and money to do the projects you do.
Is the main copper pipe coil in a resonance tank circuit with the capacitor bank?
is there a maximum temp you could heat something too with this?
Mr. Schematix , I watched your videos on induction heating, and decided to build your version of the 3000 watt induction heater. I ordered your circuit boards of course you get five circuit boards (no problem) then I ordered all the other parts. I followed your video to the best of my ability. WOW this thing works great ! Now to my problem, I got extra parts and extra circuit boards so I built another one ( now I have two). second one works just as good as first. WHAT IF I parallel the two circuit boards ? Hook up positive and negative inputs to same power supply and then hook up both outputs to ONE coil. Will I now have 6000 watts of induction heater or a bunch of sparks and smoke? I have two communication power supply in parallel with 220volt input so about 100amps available can this work or should I film it when I first hook it up?
The MOSFETs signals need to be synchronous, then you may have a chance to scale it up. And please let us know in more detail what happens.
if you hold somthing with a metal bezel that heats up , it seems like nice heat controll on object
Alternatively you can fill the tube with water and freeze it I found it this works better than using sand. Have made heat exchanger coils for condensers for large distillation purposes
So, on the subject of coils: let's assume we want to use it for forging knives. Usually this means we start off from material that's relatively flat, having a more or less rectangular cross-section. Would it be helpful to have the coils conform to this shape rather than having them be round?
Second question: since it's not a good idea to touch the coils while in operation, and since electricity can travel from the coil to your body through the tongs when the work piece touches the coil, how would you to about protecting the user from accidental contact? Would pottery enamel hold up, if we paint the coil in this? Will it adhere to the copper in the first place? Will it impact performance? Are there better options?
How about building a 6 kW or 12 kW induction heater?
I would also like to know
you could also manufacture your own toroid rings capable of handling higher inductance loads
Since you are using lead tin solder which is kinda regular solder. How about using a high quality solder that that has 6 percent silver. That would make the conductivity a lot better. What do you think fella ???
Silver solder would be a better option than lead based solder for this application (assuming you can afford it ;)
@@Schematix What else would you do to lower the electrical amperage of the unit Sir ??? Different or more capacitors, transistors. Heavier gauge wiring. WHAT Thanks
Congratulations for the project. but by the calculations it was not more than 1500w where is the 3kw? would be putting the 65V?
I'm making one of these right now, having trouble trying to find instructions on making a suitable power supply.
I made a similar induction heater and if you have them, use copper nuts and bolts to cut down on resistance at the joints
Another first class video. I will use this idea to make an instant water heater. Will pass a 3/4 inch galvanised steel pipe through the coil without touching the copper. Then push water through and will experiment with water flow . Please what is the frequency you are using. I thank you again for sharing. Firstclass project.
Please also if you can tell us the copper coil inductance.
I would like to hire you for a project if you're interested.
I can do it, if u want
I am available, too. My specialization is low voltage high current applications, such as induction heaters and solar energy inverters.
Good evening, sir! Please tell me if it is possible to power your 3000W induction heater from a welding inverter? Thanks for the answer!
2.5mm is single strand solid here in the UK. I’ve made psu busbars from hammering small bore copper pipe flat.
multi stranded wire is more rf efficient ie less loss
Can the coil be of smaller diameter and have more turns?
Since you used only one wire twelve gauge wrapping the inductor ring. Would using two wires make the efficiency go higher since resistance will be lower ???
the resistance of 1.6m of 12AWG is only 5miliohm. So the losses are negligible and not worth worrying about
@@Schematix How efficient is the induction heater in percentage Sir ???
Can you share any sources for learning about who these are designed and built? I would like to know how I can design and build my own for a specific size and power use-case.
I need an MS billet heater. 2 meters long 200*200mm square. Would you please tell the configuration
I would like to have pcb and compnent, semi assembled or fully assembled.please provide information
@Mikron this video is perfect and you should aim to have a build just like this.
How is 600v capacitor rating translated into 60v dc? 0:40 ??
Excellent video rarely found on this subject
what solder tip type did you use there @20:05? I think i have the same handle but I only have solder tips for SMD work on that.
Have you succeeded in melting metals in the crucible yet? I'd like to melt and cast silver and gold meaning that 1100C is needed.
Schematix wi do r2 r3 r4 r1 are in the scheme 1k value and 150 ohm and in your video ar 47ohm and 470ohm thx for the answer
Where did you get the lug crimping tool?
About schematic - is it sure that C15 and C16 are 2,2 microfarad (uF) or 2,2 nanofarad (nF)
Great innovation, do you sell complete induction heaters?
Değerli usta PDF de göstermiş olduğunuz şemaya göre devre elemanları kart üzerine yerleştirsek devre çalışırmı? Cevap verirseniz sevinirim..
hi; i have checked the cost of the pcb in JLC and they want close to $200 for 5 boards, I only need 1, max 2, do you have a reference number for your pcb , so I can get a more accurate quotation? of better still , do you sell the PCB your self?
kind regards
Mariano
I'm not a julous type but I'm jealous of your tools and knowledge and how did you know it was the coil making the wave wrong and not something else these induction heaters look cool what happens when you only pass water thought it does it heat the water?
brother you are very good person