Author Topic: Help for people buying the "12-48 Volt 1800/2500 Watt ZVS induction Heater"  (Read 17577 times)

Offline badpeter

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Alrighty... while the next video is being cut I'll share these, hopefully new insights.

I received my new 2 kg crucible. I chaged the coil to a 5 turn coil. This time, I WEIGHTED the crucible before use so I can see how much graphite is lost. And, it seems, a lot! After an hour runtime a 234 g crucible lost 25 grams of graphite. And I can confirm with absolute certainty that power draw depends on amount of graphite - it was at a healthy 1083 W with newly inserted crucible, and by the end was about 970 w as graphite was lost. I will not be surprized if for my next melt I will start with those 970w. The amount of material in the crucible seems to have insignificant (although measurable) effect on power draw.
So this creates a practical problem. I do not want to pay 15-20$ for a new crucible every ten melts. Also, even bigger problem is that with a tiny crucible it is very inconvenient to remelt things you have casted - you d have to laboriously cut it up in small pieces.
A truly useful crucible should be at least the size of cookie tray ingots, and good for many melts.

So, my next R and D will be devoted to being able to manufacture crucibles with clay/plaster/sand/whatever mixed with graphite. There got to be a recipe somewhere. Or switch to steel container, but I have no idea where to get something with thick walls.
Another idea is two concentric pieces of pipe acting as a heat jacket. Loose graphite can be put between the cylinders and replenished as it burns out - to keep power output consistenly high.
But at that point, I might as well design a regular electric kiln that will not have those ridiculous problems with small impractical crucibles, constant power draw issues due to burning graphite and all other sorts of maintenance that come with the iduction setup.

Anyhoo, the new vid is coming!

Offline petespaco

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badpeter:
  I just watched your earlier dagger casting video again.
If I hadn't said it earlier, I really appreciate your willingness to share.
From it I can understand your concern about being able to use your induction heater for melting that much material. 
If you have no particular attachment to "art" of induction heating, then going with an electric kiln, as you suggest in your recent post,  sounds like an appropriate solution.

However----  (isn't there always a "however"?):
I noticed that quite a bit of heat was coming out through the insulation in that video.  Whereas, the hard ceramic insulating cups that I am using NEVER show ANY signs of glowing at all on the outside.  I wonder if conditions would change significantly if you were to obtain such a crucible of the size you want.

Also--- about the depletion of the graphite:  the carbon can't really oxidize if there's no oxygen, right?   I 'm sure we have all read about commercial melters using inert gases, but that would be hard to do for us, I think.
But, what if we used a tight fitting cover?  The existing oxygen would be used up pretty quickly and then oxidation would be minimized.  We would only open the crucible to add material.   I have seen crucibles that have such a cover.
  For my own system, I will make some covers.  A guy gave me a 2" X 4" X 24"bar of graphite several years ago, so I have plenty of material  to experiment with.

For one source of graphite, the farm machinery companies around here used to sell quart size containers of powdered graphite for lubricating corn planters.  It wasn't too expensive.  Might be one approach to your inner and outer steel shell idea.  Just pour in more graphite powder as (and if) it still depletes.

Offline Bert911

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Hi,

Do you think, there is an principal limitation to the ZVS Royer circuit, like efficency or maximum Power output, compared to more complex used circuits?
Except for the savety and that it's difficult to adjust your output power.

I mean with cooled mosfets in parallel you can achieve really high currents and there are some pretty nice ones out there, which can handle 600V with fast switching like the ixth62n65x2.

Furthere more I tested the 2000W 45A 20-70V induction Heater with the LCD panel.
It uses 4 (2 parallel) IRFP260 so you really shouldn't go over 70V, tried it and got an big arc. The Heatsink was glued on and removing it would proabely also destroyed them. Now im trying the ixth62n65x2.
After trimming the Shunt with tinn the current reading was within 5% acuracy beofre it showed an 3 times lower value. It has also an poti for limiting the current below 45A, if the treshhold is reached it switches off, so it's more a protection for the power supply.
It normaly tests the ouput and the Mofets before switching on, that's a nice feature.
Unfortunaly the unit doesn't show the frequency.
I could achieve a Power consumption of 3000W. If you want, you can make a Solderbridge over one of the two Shunt to bypass/reduce the current limitation. You maybe want some watercooler for the Mosfets the, to keep the original Mosfets and therefore the Resistance down.
I worked with frequencies from 40 kHz up to 200 kHz. Not sure how well the gate signals were or if theres a way to reduced the switchable Frequency. That was a task for the future.
I already orderd a new one and the new fancy Mosfets so hopefully I can compare them.

Another tipp, the used copper pipe shouldn't be to thick. If it's to thick you maybe reduce the resistive losses, but with the thicker tube you can't achieve strong magnetic field due to the larger volume of the coil.
I'm going to use 6mm with 4.1mm inner diameter. The next lower pipe commonly aviable would be 5mm with 4.1mm that's much less area. Bigger pipes aren't not woth the extra used space in my opinion. Most cheap 15kW heaters also uses 6mm pipe.

With kind regards Robert

Offline T3sl4co1l

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Do you think, there is an principal limitation to the ZVS Royer circuit, like efficency or maximum Power output, compared to more complex used circuits?
Except for the savety and that it's difficult to adjust your output power.

And stability, because it's just a dumb oscillator and doesn't always start up at all, or at the intended frequency (more a problem for high frequency oscillators).

So yes, that's all.  Like how a car is an engine on wheels, with steering.  It's not like you need a throttle, or brakes, or a windshield. ;)

So, that's why we design more complicated circuits.  They're not very complicated really.  Tesla coil drivers have been made worse than what's needed for this.  (My typical controller circuit is implemented in about 200 components, maybe not something you really want to build a kit of, but not at all impossible.)

Tim

Offline petespaco

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T3s---:
I don't have any recent experience with "the more complicated circuits", but, regarding the "ZVS Royer circuit", please tell me more about:
Quote
---doesn't always start up at all, or at the intended frequency (more a problem for high frequency oscillators).

I ask because I don't think I have had either of these problems.


Offline hightemp1

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 ::)
Alrighty... while the next video is being cut I'll share these, hopefully new insights.

I received my new 2 kg crucible. I chaged the coil to a 5 turn coil. This time, I WEIGHTED the crucible before use so I can see how much graphite is lost. And, it seems, a lot! After an hour runtime a 234 g crucible lost 25 grams of graphite. And I can confirm with absolute certainty that power draw depends on amount of graphite - it was at a healthy 1083 W with newly inserted crucible, and by the end was about 970 w as graphite was lost. I will not be surprized if for my next melt I will start with those 970w. The amount of material in the crucible seems to have insignificant (although measurable) effect on power draw.
So this creates a practical problem. I do not want to pay 15-20$ for a new crucible every ten melts. Also, even bigger problem is that with a tiny crucible it is very inconvenient to remelt things you have casted - you d have to laboriously cut it up in small pieces.
A truly useful crucible should be at least the size of cookie tray ingots, and good for many melts.

So, my next R and D will be devoted to being able to manufacture crucibles with clay/plaster/sand/whatever mixed with graphite. There got to be a recipe somewhere. Or switch to steel container, but I have no idea where to get something with thick walls.
Another idea is two concentric pieces of pipe acting as a heat jacket. Loose graphite can be put between the cylinders and replenished as it burns out - to keep power output consistenly high.
But at that point, I might as well design a regular electric kiln that will not have those ridiculous problems with small impractical crucibles, constant power draw issues due to burning graphite and all other sorts of maintenance that come with the iduction setup.

Anyhoo, the new vid is coming!


Bads, come on -- cut that sucker - how did everything turn out !!!

On the narrow crucible problem.  Agree, cutting up castings, etc. to fit these narrow crucibles is a pain.  Suggestions include making and pouring your own alloys into self-made pre-heated ingot molds that are long & narrow.  Also, I have seen wide-body graphite crucibles, but I think stirring increases with width so a less conductive alloy may be advised?  I cut up pieces using a band-saw, or saws-all.

Making own crucibles and eliminating oxygen are both good ideas but may be difficult.  Clay bonded crucibles may not get the heat we want?  Possibly ramming  graphite within a concentric 1 piece u-shaped steal tube, then sealing top with high temp ceramic that hopefully seals off oxygen?  With copper alloys, you then have to apply some sort of hot face lining to the inner metal to prevent metal contamination - similar lining would be necessary for an all stainless steal crucible?  Obstacles include longevity of lining, metal, and O2 elimination, plus cost competition with graphite.

Dross/slag further limits crucible life so using alloys that don't require as much additives may extend crucible lives.

  Losing 10% or more each melt means that after 6 melts crucible is reduced by half and since the crucible is what is heating/melting our metal, you are correct this is a big problem. Assuming $21/crucible & 7 melts/ crucible life -that is $3 crucible cost per melt - approximations only - not good ?  Three dollar crucible cost would be approx 10x the energy cost (assuming 1000 watt for 1 hour ?).  I see that the alternative furnaces that use electric resistant elements may also be using 100% graphite so crucible life may not be much longer?  However, by nature I would think that clay-type crucible would be usable with resistance furnaces so crucible life may be 2-3 Xs longer  - but maybe heat time/Watts consumed go up ??  Fatter graphite, like 10mm thick or more would be nice but where to source economically?  Lastly, with the power limitations we have on our ZVS units, we are pushing the limits on max. quantity of metal that can be realistically melted.  Personally, I hope to be able to melt 1 to 3 pounds of copper alloys into useful castings weighing two ounces to two pounds.  That is more than 10 times what an acetylene torch can melt, and quieter/cleaner than a propane setup.  Alternative as we both know is resistance melting.  I did not think of or compare the two methods beforehand so hopefully induction will work out.

As you can see,  I mostly only have more questions to your questions.    :-\ 
To some extent, we are pioneers here, discovering, solving, understanding problems as we go.  Many here at not at all interested in the melting side of things and only want to create large sparks.  ::)
« Last Edit: June 10, 2019, 02:27:29 PM by hightemp1 »

Offline petespaco

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This isn't really a "reply" to previous posts, but just a tiny bit of additional information  about the molten copper----

I just uploaded this youtube video about the looks of the surface of the molten copper:
/>
It's not my best work, but just another step toward better photography.
I also measure the temperature of the molten copper a couple of times.
I'm in the process of making several improvements that I hope will benefit those of you who haven't yet actually peered into a ZVS induction heater's graphite crucible with molten copper in it.

Offline hightemp1

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Do you think, there is an principal limitation to the ZVS Royer circuit, like efficency or maximum Power output, compared to more complex used circuits?
Except for the savety and that it's difficult to adjust your output power.

And stability, because it's just a dumb oscillator and doesn't always start up at all, or at the intended frequency (more a problem for high frequency oscillators).

So yes, that's all.  Like how a car is an engine on wheels, with steering.  It's not like you need a throttle, or brakes, or a windshield. ;)

So, that's why we design more complicated circuits.  They're not very complicated really.  Tesla coil drivers have been made worse than what's needed for this.  (My typical controller circuit is implemented in about 200 components, maybe not something you really want to build a kit of, but not at all impossible.)

Tim

Just curious Tim, for you, how hard would it be to mod this board so amps could be approximately maintained throughout melting process? 

In Peter's bigger melting videos amps start out at about 38 and finish somewhere around 25.  That is a 33% loss or about 600 watts of power. ???
« Last Edit: June 10, 2019, 02:23:17 PM by hightemp1 »

Offline T3sl4co1l

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T3s---:
I don't have any recent experience with "the more complicated circuits", but, regarding the "ZVS Royer circuit", please tell me more about:
Quote
---doesn't always start up at all, or at the intended frequency (more a problem for high frequency oscillators).

I ask because I don't think I have had either of these problems.

Startup is an issue at very low Q factors.  Transistor gain is quite high so it's not usually an issue at common Q factors.

You might just see it with copper coils tightly fitted around steel pipe, or with lossy coils (say a stainless pipe coil used for process heating).

Frequency is a problem for this circuit for example,



which runs around 500kHz, but can lock into other modes in the 400-650kHz range depending on what load you have attached.  The problem is if there is extra capacitance at the load, in addition to what's on the oscillator board itself.  The connecting wires between oscillator and load form another resonant circuit, and the frequency response becomes much more complicated.  In this case, the transformer is a step-up and its secondary has a resonance near this frequency, even if I didn't put explicit capacitors on it.

As I said, you're less likely to have problems with this, at low frequencies where the capacitors are more likely to act together.

Tim

Offline hightemp1

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This isn't really a "reply" to previous posts, but just a tiny bit of additional information  about the molten copper----

It's not my best work, but just another step toward better photography.
I also measure the temperature of the molten copper a couple of times.

Peter, what interested me the most in your last video me is after the melt & pour when the emptied crucible was reinserted inside coil, the amps shot way back up to 38.  This tells me that maybe very little graphite was lost in the approx 15 minute melt.  More curiously, is that the reduced amps from melt start to melt pour (38a to 25a, or 33%) simply seems to have more to do with the metal going from solid to liquid state - maybe how this self-oscillation circuit mysteriously works - can someone please explain to me why amps crash so much from cold metal to melted metal, or am I just missing something obvious again?? 

Oddly, on Bad's last reported melt the amps only went down approx 10% in an hour.  Not sure if amps would have recovered if he had reinserted the empty crucible into coil after melt.  So Bad's 1800w board appears to behave differently than Peters's 2500W board, but there is also different starting power input levels (1kw vs. 1.8kw), and different run times (15 min vs. 60 min) so comparison is fuzzier. However, possibly a huge difference in individual board behavior. Bad's smaller amp loss may be due more to crucible burning and Peter's larger amp loss may be due to board design, self-oscillation??

Also, the blue gas burning was clearly evident towards end of the video so I am thinking crucible burning is accelerated as crucible temp increases.  Blue flame may have just been some crude on copper too.

update: Lastly, the pryometer went up to about 2015f and then you said that it stopped climbing rapidly.  I suppose it could have gotten to 2200 but just would have taken progressively longer?
« Last Edit: June 10, 2019, 09:15:55 PM by hightemp1 »

Offline T3sl4co1l

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When the load resistance is low (e.g. cold copper), it tends to reflect rather than absorb magnetic field; this reduces power consumption compared to a better matched load.

Whether current draw increases or decreases with heel size and temperature, depends on which side of best match you're running at.  Which in this case I think depends on the crucible thickness, and porosity (overall conductivity), as far as how much magnetic field it absorbs before reaching the copper within.

Tim

Offline hightemp1

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When the load resistance is low (e.g. cold copper), it tends to reflect rather than absorb magnetic field; this reduces power consumption compared to a better matched load.

Whether current draw increases or decreases with heel size and temperature, depends on which side of best match you're running at.  Which in this case I think depends on the crucible thickness, and porosity (overall conductivity), as far as how much magnetic field it absorbs before reaching the copper within.

Tim

Cool, so if I got it right - the higher the metal temp the higher the metal resistance, then the higher the resistance the lower the power output of unit.  Thought there might be a relationship.  This could be my downfall since I would like to melt higher resistance alloys like silicon bronze that have very high resistances = not enough heat to melt.  Unfortunately, most of the good copper casting alloys have very high resistances.  Also, bad for me is the less resistance the greater the stirring.  The intricacies of induction melting are challenging.  Will try to squeeze all the power I can out of a 2500w unit but it may prove to be under powered for my size melts.  Please correct me if my resistance/zvs power relationship is wrong - thank you!
« Last Edit: June 10, 2019, 11:02:15 PM by hightemp1 »

Offline petespaco

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There is very little increase in current, if ANY as the copper heats up (but before it melts).  The decrease in current that I report occurs at exactly the moment when the copper melts.  That has been my direct observation EVERY time I have melted copper.  And, the deeper the pool of molten copper, the more the current decreases.
  I don't see the "cold copper" phenomenon mentioned recently.
Also, since the addition of solid copper to the crucible does not seem to increase the current, I don't think the copper itself is participating to any significant extent in speeding up the melt.    It's radiation, convection and conduction that is transferring the heat from the glowing crucible walls, to the copper, in my opinion.
  ---So I will go "out on a limb" and say that I don't think the copper alloys that you want to use will present any worse of a melting problem than does the copper that I am using. 

Now for my hypothesis as to why the current drops just when the copper melts:  I think the molten copper actually "shorts out" the graphite as the copper makes intimate contact with the whole wall of the crucible.   

Lastly, for today, about stirring:
As you know, I am trying to be able to show exactly what is going on in the bottom of the crucible.
  I almost got to performing  my improved camera color-shift filtering test today, but--
A friend and I had a chance to inspect a pig iron smelter from the 1880's and we did do it.
Well worth the 20 mile trip.

  I hope we will all see that there isn't much "violence" going on in the crucible, after all.
I did get some graphite covers and additional insulations pieces cut and did a dry run to test for a 2 camera shoot, though.

Offline hightemp1

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  ---So I will go "out on a limb" and say that I don't think the copper alloys that you want to use will present any worse of a melting problem than does the copper that I am using. 

Now for my hypothesis as to why the current drops just when the copper melts:  I think the molten copper actually "shorts out" the graphite as the copper makes intimate contact with the whole wall of the crucible.   

Lastly, for today, about stirring:

Absolutely, videos clearly show amps dropping once molten metal bath starts and peek when the pot is full (38a to 24amps, I think) - somehow the molten metal bath inhibits power getting to the graphite.  Now we kinda know why amps crash so much, but unless we can rig up some kind of controller circuit to force more power to crucible I guess just knowing exact cause doesn't do much good anywho.  Tim, stated that they are not really complex for him.  Adding two hundred components is way beyond my pay grade.  But possibly something less complex, that just gives a little more power would be sweet??

According to my SI calculations copper, silver, gold (the super-conductive elements) all have very high stirring indexes.  This has been confirmed by one of the retailers of these units, for what that is worth.

I would have liked to have seen the old-time pig iron smelt - make America great again! :(

update: Just got my crucible, like yours.  A little dissappointed how thin the graphite is (11mm top rim, and a little over 6mm body).  Also was hoping the graphite would sit flush with the ceramic shell, but instead graphite is 2mm higher so minimizing O2 to outer graphite would be more difficult.
Also, received the 1.5kg the other day.  No shell and the body is 8mm thick.  Thought about coating it with that high temp spray kit, but that stuff is so expensive and I've heard that because graphite is so slippery that it may not hold for very long.

« Last Edit: June 11, 2019, 09:09:53 PM by hightemp1 »

Offline petespaco

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Sorta OT, but---
Quote
I would have like to have seen the old-time pig iron smelt - make America great again! :(

This smelter hasn't actually been in operation since about the year 1900.  We just checked it out for historical curiosity sake.
See:
https://www.youtube.com/edit?o=U&video_id=0zTf4WdYXc0

If you want to see us MAKE "Wrought Iron" from iron ore, go here:
https://www.youtube.com/edit?o=U&video_id=493AsqZ4P54


Offline hightemp1

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Sorta OT, but---
Quote
I would have like to have seen the old-time pig iron smelt - make America great again! :(

This smelter hasn't actually been in operation since about the year 1900.  We just checked it out for historical curiosity sake.
See:
https://www.youtube.com/edit?o=U&video_id=0zTf4WdYXc0

If you want to see us MAKE "Wrought Iron" from iron ore, go here:
https://www.youtube.com/edit?o=U&video_id=493AsqZ4P54

links did not work, for me?  Any ideas for a "simple" -more power" controller board add-on for these heaters?

Offline petespaco

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Quote
links did not work, for me?  Any ideas for a "simple" -more power" controller board add-on for these heaters?

Hmmm--- I just tried both links and they did work for me.  Just a simple "click" on each one and there I was.

I don't have any idea for a "more power" controller board to add on.  However, maybe you want to bit the bullet and buy the $1000 unit that is 7 KW.
https://www.ebay.com/i/221663967797?chn=ps
(This is just one of the many sellers)
  That ought to do it.  You will, however, need a TIG  water cooler for it and they run at least $400 more.

I still feel that it's a "heat in vs heat out" equation.  You only get 3412 btu's of heat for each 1 KW of electricity.  So, if you are losing more than you are putting in, the temperature quits rising, right?   There is still the opportunity for any or all of us to conserve more heat.

Offline badpeter

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Alright people, here it is...
Thank you for the valuable suggestions - I did not think of oxygen issue at all. I wonder how less the deterioration will be if I add either a ceramic shield or somehow make the whole thing happen in CO2 atmosphere (yes, for my kind of "lab" that be a bit of an overkill!)
I will probably entertain the idea of getting a drilled out STEEL crucible somewhere. Will need to be very creative with that. (Curie point a possible issue?).
Will do maybe one more melt/vid with graphite crucible, not to get too repetitive.
Anyways, the current vid is self-explanatory. lots of commentary and measurements given.
If I cleared PLA, it would have worked wonderfully.
Wonder if i should melt the sphinx (since its not great) or leave it as souvenier and recast my dagger with new material (i found a small source of copper recently!)


Offline hightemp1

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Alright people, here it is...
Thank you for the valuable suggestions - I did not think of oxygen issue at all. I wonder how less the deterioration will be if I add either a ceramic shield or somehow make the whole thing happen in CO2 atmosphere (yes, for my kind of "lab" that be a bit of an overkill!)
I will probably entertain the idea of getting a drilled out STEEL crucible somewhere. Will need to be very creative with that. (Curie point a possible issue?).
Will do maybe one more melt/vid with graphite crucible, not to get too repetitive.
Anyways, the current vid is self-explanatory. lots of commentary and measurements given.
If I cleared PLA, it would have worked wonderfully.
Wonder if i should melt the sphinx (since its not great) or leave it as souvenier and recast my dagger with new material (i found a small source of copper recently!)

/>

You know what they say Bads, third time is a charm - I vote for the dagger :)  Just remember, they are never perfect and will almost always need finishing of some sort.  If you like polished look a skilled finisher can do miracles but does take time and experience.  Personally I prefer the as cast look with minimum finishing, but you really need clean castings, good mold design, etc. for best results. 
Don't know anything about PLA but maybe it is similar to wax and needs a 1200f burnout cycle? 
Steel crucible may work, considering you'd like a 1-5 percent iron in your dagger; though, I really have no clue how much iron would be absorbed, and if too much is absorbed it may freeze.  Also, could get contamination of other elements depending on composition of steel?  I would think it would be physically safe, but Peter would know much better than me how strong various steel crucibles may be at 2200-2300 degrees and maybe recommend some type of steel. 
I really don't know how to tackle the burning crucible issue.  I previously mentioned some ideas but they are experimental only.  Go to go for now - thanks much for posting!

Update: Just thought of one potential problem with molding the dagger -- maybe the large thickness transition  between the handle and the blade.  I don't know the best way to design it.  Possibly, have the handle act as sprue, probably have more of a taper transition between the handle and the blade, and/or place a core in the handle so overall thickness will be more uniform?  This will of course be just one the many possible molding, casting, finishing, etc. problems you many encounter.
« Last Edit: June 12, 2019, 02:08:38 PM by hightemp1 »

Offline Bert911

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Just a quick response from my side.

The higher the resistance of the material, the better it is for heating it. Steel for example, it starts with 60% power than rises to 100% due to increasing electrical resistance and goes down to let's say 40%. These are just estimations, based on my analogue 80a current meter.

So getting up with the temperature is for non magnetic materials in theory better. That would at least explain the overall low power consumption for these relatively high voltage.

For a steel crucible, I can say the following. The normal steel will get destroyed from the air/oxygen and the aluminium, starting at 700°C/1292°F. For example a 2mm thick steel crucible will be destroyed after around 10h to 20h completely unusable at 900°C. Steel with 25% Cr, 20% Ni will withstand the oxygen in this temperature but will still be "eaten" by the aluminium. There are some coatings which slow the process like "3M Bornitride Suspension WP"

http://technical-ceramics.3mdeutschland.de/en/products/3m-release-agents-and-lubricants.html#c880

Cost in Germany around 40€ for 1 litre.
They also have other coatings. But they only slow down the process. They are likely to crack and there is the crap happening again....

For controlling the real power of a ZVS Circuit, you can basically only lower the input voltage, for all the other stuff you have to change components on the board.

Best regards Robert

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Today at 04:03:42 AM
post Re: Next Gen DRSSTC
[Dual Resonant Solid State Tesla coils]
acobaugh
Today at 01:40:51 AM
post Re: Problems with my first DRSSTC
[Dual Resonant Solid State Tesla coils]
bozidar
October 22, 2019, 07:44:55 PM
post Re: making a useable induction forge.
[Transformer (iron core)]
rustedone
October 22, 2019, 05:56:52 PM
post Re: Van de Graaf is leaking charge
[Static electricity]
nik282000
October 22, 2019, 04:56:19 PM
post Re: Beetle in a Geißler tube
[Science, research and news in other fields than electronics]
shrad
October 22, 2019, 02:51:27 PM
post Re: Phoenix's Large DRSSTC II
[Dual Resonant Solid State Tesla coils]
Phoenix
October 22, 2019, 12:38:33 PM
post Re: Phoenix's Large DRSSTC II
[Dual Resonant Solid State Tesla coils]
shrad
October 22, 2019, 12:26:39 PM
post Re: Phoenix's Large DRSSTC II
[Dual Resonant Solid State Tesla coils]
Phoenix
October 22, 2019, 11:38:31 AM
post Re: Phoenix's Large DRSSTC II
[Dual Resonant Solid State Tesla coils]
shrad
October 22, 2019, 09:48:57 AM
post Re: Next Gen DRSSTC
[Dual Resonant Solid State Tesla coils]
Hydron
October 22, 2019, 08:51:33 AM
post Re: making a useable induction forge.
[Transformer (iron core)]
rustedone
October 22, 2019, 08:38:14 AM
post Re: QCW Capacitor Torture Testing
[Dual Resonant Solid State Tesla coils]
Weston
October 22, 2019, 07:32:56 AM
post Re: Next Gen DRSSTC
[Dual Resonant Solid State Tesla coils]
acobaugh
October 22, 2019, 06:05:00 AM
post Re: making a useable induction forge.
[Transformer (iron core)]
Weston
October 22, 2019, 03:27:46 AM
post Re: Phoenix's Large DRSSTC II
[Dual Resonant Solid State Tesla coils]
Phoenix
October 22, 2019, 12:13:05 AM
post Re: making a useable induction forge.
[Transformer (iron core)]
rustedone
October 21, 2019, 10:00:06 PM
post Re: making a useable induction forge.
[Transformer (iron core)]
rustedone
October 21, 2019, 09:56:51 PM
post Re: making a useable induction forge.
[Transformer (iron core)]
Weston
October 21, 2019, 09:45:49 PM
post Re: Phoenix's Large DRSSTC II
[Dual Resonant Solid State Tesla coils]
shrad
October 21, 2019, 09:03:49 PM
post Re: making a useable induction forge.
[Transformer (iron core)]
rustedone
October 21, 2019, 08:28:07 AM
post Re: 50KVA generator on a 4 cylinder Dorman diesel engine
[Electronic circuits]
johnf
October 21, 2019, 07:50:47 AM
post Re: Phoenix's Large DRSSTC II
[Dual Resonant Solid State Tesla coils]
Phoenix
October 21, 2019, 07:07:43 AM
post Re: Help for people buying the "12-48 Volt 1800/2500 Watt ZVS induction Heater"
[Electronic circuits]
petespaco
October 21, 2019, 01:24:00 AM
post Re: 50KVA generator on a 4 cylinder Dorman diesel engine
[Electronic circuits]
DICKEYBIRD
October 20, 2019, 10:39:59 PM
post Re: Help for people buying the "12-48 Volt 1800/2500 Watt ZVS induction Heater"
[Electronic circuits]
DICKEYBIRD
October 20, 2019, 10:34:22 PM
post Re: QCW Capacitor Torture Testing
[Dual Resonant Solid State Tesla coils]
Hydron
October 20, 2019, 12:27:54 PM
post Re: QCW Capacitor Torture Testing
[Dual Resonant Solid State Tesla coils]
klugesmith
October 19, 2019, 10:15:56 PM
post More things wanting homes
[Sell / Buy / Trade]
klugesmith
October 19, 2019, 09:56:15 PM
post How to get rid of stuff?
[Sell / Buy / Trade]
klugesmith
October 19, 2019, 09:43:02 PM
post Re: making a useable induction forge.
[Transformer (iron core)]
rustedone
October 18, 2019, 05:35:02 PM
post Re: making a useable induction forge.
[Transformer (iron core)]
T3sl4co1l
October 18, 2019, 04:29:03 PM
post Re: making a useable induction forge.
[Transformer (iron core)]
rustedone
October 18, 2019, 02:09:23 PM
post Re: making a useable induction forge.
[Transformer (iron core)]
rustedone
October 18, 2019, 09:00:52 AM
post Re: making a useable induction forge.
[Transformer (iron core)]
T3sl4co1l
October 18, 2019, 08:05:06 AM
post Re: Problems with my first DRSSTC
[Dual Resonant Solid State Tesla coils]
davekni
October 18, 2019, 06:30:06 AM
post Re: so far video
[Spark gap Tesla coils]
thedoc298
October 18, 2019, 04:42:52 AM
post QCW Capacitor Torture Testing
[Dual Resonant Solid State Tesla coils]
Weston
October 18, 2019, 02:41:44 AM
post Re: Problems with my first DRSSTC
[Dual Resonant Solid State Tesla coils]
bozidar
October 17, 2019, 05:53:09 PM
post Re: making a useable induction forge.
[Transformer (iron core)]
rustedone
October 17, 2019, 05:09:29 PM
post Re: making a useable induction forge.
[Transformer (iron core)]
rustedone
October 17, 2019, 04:04:53 PM
post Re: making a useable induction forge.
[Transformer (iron core)]
T3sl4co1l
October 17, 2019, 11:30:19 AM
post Re: making a useable induction forge.
[Transformer (iron core)]
rustedone
October 17, 2019, 10:59:31 AM
post Re: making a useable induction forge.
[Transformer (iron core)]
Bert911
October 17, 2019, 10:02:12 AM
post Re: making a useable induction forge.
[Transformer (iron core)]
rustedone
October 17, 2019, 08:19:19 AM
post Re: making a useable induction forge.
[Transformer (iron core)]
Bert911
October 17, 2019, 07:57:58 AM
post Re: making a useable induction forge.
[Transformer (iron core)]
T3sl4co1l
October 17, 2019, 06:19:14 AM

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