Show Posts

This section allows you to view all posts made by this member. Note that you can only see posts made in areas you currently have access to.


Messages - Bert911

Pages: [1]
1
So many posts  :D

What applications for this induction heater do you have in mind?
Can you tell us the frequency of operation and inductance of that pancake work coil?

For now, I'm using an induction heater for my diploma thesis, later I want to use it for metal working, losing screws, heat treating and cleaning. Heat works like a charm for removing grease or paint, no chemicals needed.
This coil runs at 86 kHz with 0,86 µH of inductance.
From my tests for pancake coils I noticed a drastic increase of loss in the inner winding the smaller the inner diameter gets.
I wouldn't recommend smaller than 25mm, better higher.

I've recently found some good references on painting a ceramic coating on (by yourself) to
standard graphite crucibles though; that should help a lot to avoid oxidation. Heating for
a full hour might require a different coil setup, loading method, etc.

I used some coating for stainless steel containers to protect it from the aluminium:
3M Boron Nitride Suspension WP

http://technical-ceramics.3mdeutschland.de/fileadmin/content/download/produktinformation-EN/PI_boron_nitride_suspension_wp_e.pdf

The coating works great but is very sensitive to mechanical scratches, but there it's undamaged it's doing a great job of protecting the steel.
At the damaged area, the 12 mm thick steel was eaten away during 4 hours!

I have looked at the schematic, since Rehmann has it protected I assume it is quite good.
Would you mind showing us yours, ie with parts?
You use a separate power supply of 18V (always on) instead of the R1,ZD1/C1 net? And
100VDC feed of course?
I guess the schematic lends itself to an LTSpice simulation or two...
I have a bunch of 48V server supplies, some NOS (2000W) and some legendary ESP120 (used)
that I was thinking of series connection two for 100VDC (well 102,8 V nominally...) . I
was just wondering how to protect them, I assume distance (ie cables, inductive decoupling
by series inductances, over voltage protection (fast) )

LTSpice isn't that good at simulating IGBTs, I couldn't get it to work and I don't think the simulations are representative anyway, since ringing and non linear inductances may occur.

The boom of this circuit is attached and can be loaded directly into Digikey. I used the MUR1560 diode in the circuit, which is totally over dimensioned, but the size of it bothered me the most.
I would recommend the MUR460 in the circuit and two MUR1560 at the input terminals.
I can't give any recommendations for the inductors since I don't know the value and the one's from Digikey aren't really suitable.

I have some normal reset able house fuses in parallel for some simple current protection, but if they switch, there could be a huge voltage spike, which should be covered with the MUR1560 Diode at the input.
I used a 12V power supply for the fan and the cheapest dc-dc converter from ebay to generate 20V, which is then reduced to 18V, not that necessary, but won't hurt anyway.

https://www.ebay.de/itm/3x-XL6009-DC-DC-Boost-Modul-Step-Up-LM2577-Schaltregler-Konverter-Arduino/252796314014?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649

The fan and the control voltage is always on, it is safer to apply the control voltage before the main voltage for a safe oscillation.
I like to slowly increase the supply voltage to see how the current rises.
I also use a power relay to switch the transformers on and off but I have done this just up to 30A to reduce the inrush currents.
You could simply switch the supplies on and off.

Next week I can make some close-ups from the circuit.
Since the circuit components aren-t that expensive I will build a new version with 4 IGBT'S (two in parallel) with some better hose management.

2
Hi everyone,

Last week I finished my own ZSV heater circuit.
After some many cooling problems and my first self made water coolers it worked great.
The circuit from Jörg Rehrmann works fantastic with no issues.
The capacitor from Eectech has 4.0µF 400Vrsm 700Arms and don't get that warm.
For cooling I have two of the Chinese water pumps in parallel, of course watercooled (they get really hot after some time) with a 30 litre canister.
With pancake coils the circulated water is around 30 °C warmer than the supply water.
With my nice case I can touch most of the heater without shocking my self.
I confirmed 5kW at 50A and 100V at the input. The water cooled IGBT are getting up to 80°C at 50 A, that's OK, not great but solid.
I plan to make some more professional water coolers and upgrade the pumps, the cooler the system runs, the more efficient it gets.

For me the 650V IGBT are more than enough and it was the right decision to not use the not so suitable 1200V IGBT.
The stainless steel is glowing at 1150 °C and was melting from behind.  :o

3
Hi to everyone,
My intension to use the original 2000W ZVS circuit with other Mosfets/IGBTs wasn't a success.
Furthermore, due to the non optimized control for the IGBT the new ones died again after around 30s of solid working with no obvious reason, no ringing at the gate or so. The build in fail-safe, which should open the relay in case of an over current, didn't work and the relay welded itself to a permanent on position.

After that I salvaged the few remaining parts.
I'm now going to use the circuit from Jörg Rehrmann.
I will have LESS fail-safe options, but these can handle the current and voltages regardless of the case.
It's basically just a mains fuse at the DC side, which won't like the DC, but it's cheap and will do the business and a large primary contactor, which is manually controlled. So I can decide, when it's too much current.
With my analogue ammeter I can assume the used power.

http://www.joretronik.de/Oszillatoren/Oszillatoren.html
Last one on the site. I'll keep the 18V control-voltage always on and switch the primary voltage, so the IGBT's won't come in strange half open states.
According to the designer, this circuit should always oscillate.

The Chinese board always switched off randomly even at 75% Voltage/current, that was a pain, it randomly said over current/voltage/temp....

So my inertia question:
Is the circuit capable for higher power level --> I wouldn't recommend it for more than 1,5kW.

4
Good thing that my multimeter can handle these frequencies, after making a new coil it's always interesting how the inductance is.

As I said earlier I had some ringing Problem with the IXTH62N65, because of there really slow body diode (typ. at 25°C 445ns).
As a comparison, the IRFP260N (typ. at 25°C 268ns) there's also some ringing but it's not consistent and gets better with heavy load.
I also tested some FGH80N60 (typ. at 25°C 61ns).

The FGH80N60 worked just fine but they got really hot.
So I ordered some IKW50N65 (typ. at 25°C 52ns) which should be fast and cool enough. I'm not sure how the relative slow turn off delay time will matter, but I'll see.

The next step for 200V input voltage would be some good capacitors, but there are the next problems.
With these high frequencies and "high" voltages of the standard 2000W heater model, the capacitors are already at there current rating with only 50V input.
So that's not a long term solution. Other similar capacitor like the used MKPH-R or Dawncap aren't that suitable. If the overall capacitance is too low the frequency rises, which is a bad thing for the slower IGBT. If the capacitance per capacitor is too high, the currents are way above the ratings.
So more small capacitors would be the way to go, but these won't fit more than four on the original board.
I could make a new board/circuit, but the start/stop routine works really good and I want to keep it (no need for turning off the big PSU...).

With 4 capacitors which cost 15 to 25 € I can also go with some seriously big stuff like this:
http://www.eectech.store/cs-30122-solid-state-high-frequency-film-capacitor-12uf-500vac-p0319.html
Which can handle the voltage, current and frequency. It's even smaller than 4 big film caps. With some cutting at the PCB it will fit nicely.

However, my previously statement with the 6mm copper pipe isn't true in that case and a10mm pipe is probably more suitable.
Since I have two units, I put 4 originals caps on the IRFP260N unit with 6mm; 1/4" connectors and the second one with the new cap, IKW50N65 and 10mm; 3/8" connectors.

That should power things up. The oscillating current should increase with the higher capacitance which lead to a smaller working coil, which should be better for screws and non crucible stuff, which I use it for.

There's also a mains powered updated version of this circuit:
http://www.joretronik.de/Oszillatoren/Oszillatoren.html
This can't hang up at start up and can't fail like the royer.
Since my PSU is limited somewhere to 4kw-6kw I don't see a need to go higher up in voltages/complexity right now.
I'm not that firm with high energy stuff at that high frequency. For a proper circuit you would need a start/stop routine, over current protection, a relay and so on.
I try to get this thing working, build a housing and that's it, since i have seen many "super big" induction heater projects which never finished...

5
I finished the circuit for the unit.

Thank you for posting that!  I think that explains the 6 small transistors I was seeing in the ebay pictures.  I tried to ask about it in this thread:

https://highvoltageforum.net/index.php?topic=167.0

So the 12v for the gate drive comes from a separate DC-DC board?

Also, what is the big capacitor that is not part of the tank?  Is this C8 in your diagram?

Finally, are there no bypass capacitors on the supply to Q3 and Q4?  If not, I would be curious to see what this point looks like on a scope.


Hi there,

The first transistor switches the supply voltage for the gate drivers on/off, the second one switches the relay and the other 4 are the gate drivers.

There's an additional 12V power supply for the microcontroller, fan, pump and the gate circuit.

The capacitor C8 reduces the current/voltage spikes during the mosfet switching, reduces the impact of wiring inductances from the power supply and smooths the measured voltage for the microcontroller.

The transistors have no additional parts, there is no gate resistor, unfortunately.

I tested my new arrived "IXFX100N65X2-ND" mosfets and they didn't really work. During the ordering I didn't notice the slower body diode.
The heater didn't turn on at voltages over 40V or with a load and stalled at 20A current using. So I hooked up my Tektronix 2225 with my "very fine" 100:1 Chinese probes and measured the gate signal with the analogue differential add function. With no loads it was a near perfect square wave, not like the simulated one, but with increasing current the ringing was really visible.
Like 20V peak-peak at 20A. Could be a bad measurement setup, the Chinese probes or most probably the slow diodes.

Similar to this, just worse:
https://highvoltageforum.net/index.php?topic=648.msg4550;topicseen#new

As supposed here, it gets worse with the rising current.
https://www.mikrocontroller.net/topic/207864#2057621

Also the Voltage in the oscillator tank dropped at 20A to 60% from the unloaded one.

So I'm waiting for the real 260n mosfets, measure them with the scope and maybe buy some other mosfets with higher voltage ratings.
Something like these:
https://www.digikey.de/product-detail/de/rohm-semiconductor/SCT3030ALGC11/SCT3030ALGC11-ND/6204894

But I want to check the circuit with the original mosfets first, maybe they are also ringing, but with them it doesn't matter as much.

Greetings

6
Hello everyone,

I got around to test the new arrived heating unit. It came with a different coil (4 instead of 6 windings).  I have to correct my thought about the current limiting potentiometer. It's a bit strange, you can limit the current and you can trim the shunt resistor.Therefore, a real current meter is a have to. Maybe it's some sort of current limiting in the first 50% and shunt tuning with max current at the last 50% or something.

Here are the results from some testing:
Coil with 6 windings, 50 mm high, 45mm inner diameter
with no workpiece:
In 24,4V 45W; Out 74V peak on the caps
In 38V 90W; Out 112V peak on the caps
In 50V 185W; Out 152V peak on the caps
In 60V 250W; Out 188V peak on the caps
The voltage over the caps are pretty much spot on the PI times input voltage. Due to the higher oscillating current, the power loss increases also.

Heating up a workpiece:
Steel bolt 22mm diameter and 60 mm high
In 52V, used power 1600W at beginning, 2100W peak and 700W at around 900°C.

I maybe solder a copper pipe direct at the capacitor connection to cool them with the water too. A cooled heat sink for the mosfets would be great to, since the get a little bit warm at high currents.

The used resistor is a 5.1 Ohm, so I updated the schematics, the simulation is much more stable now.

7
Thanks for clearing that up and thanks for the link.  Now I understand that there's a lot more going on than I thought.
That's quite a package!
When I multiply 65V X 45A, I get 2925 watts.  I wonder why they only rated it as a 2000 watt unit.

Robert, 2.2kw was stable?  maybe making this a superior design & deal?  Input, 120 or 240, make any difference on output?  2 to 2.5kw area makes a 20 amp circuit on 120 volt doable.

Update:  Per Product Description - (Short Circuit/Overload: Input current is greater than 40A, voltage greater than 55V, enter protection).   If so designed, then should not go over 2.2kW, I presume.


The heater goes in protection mode, if the voltage is below 20V, greater than 70V, current greater than 48A or the heat sink temperature over 65°C.
Even fast peaks are detected and trigger the protection.

The mains voltage doesn't matter at all, the input voltage of the unit is relevant. Btw my supply uses 3x380V.

Note that the idle loses increases with a higher input voltage, but also the heating capacity of the coil, it also increases the oscillating current through the coil. So the capacitors need to handle these extra current.
These caps are rated for 50A effective current, this is already reached at 54V input voltage and the standard coil.

ICap, peak=2*Pi*f*UCap,peak
UCap, peak≈Pi*Uinput             // measured Peak Voltages from multimeter could be off by 50% due to high frequency
ICap, effektive≈ICap, peak/1.414

This oscillation current through the caps shouldn't depend on the load.
With 3kw input wattage there could easily be a loss of 500W or more.

Pworkpiece=Pinput-Pcoil+cap-Pmosfet-Premaining circuit
Pworkpiece≈Pinput-Pidle-Pmosfet

The mosfet losses can be assumed to be relatively small, probably under 100W with that heat sink. These depend on the Input current/voltage and switching frequency.

The 48A is already a seriously big current that's why I bought some new mosfet with a higher voltage rating. A heating power of effective 2kw at the workpiece is most likely enough for most applications, but you can't always reach this with the standard configuration for specific shapes like bolt heads.

8
The µC stands for microcontroller.
I didn't bother to track the all the way back to it.
Of course this isn't the whole schematic since there is also an lcd display.

https://www.banggood.com/2000W-ZVS-Induction-Heating-Module-Board-Flyback-Driver-Heater-Good-Heat-Dissipation-With-Coil-Pump-Power-Adapter-Kit-p-1464491.html?cur_warehouse=CN

5V worth arguing? Rule of thumb is 4 times.

9
I updated the schematic a bit (removed the 1k resistor after the relay) and there are two versions now.
One with the real component names and one for ltspice simulation with other components.

If the relay is open, the voltage over c3 and c4 goes up to 22V, after that the unit can activate the mosfets and recognize a voltage drop.
If the mosfets are shortened or the transistors are damaged the voltage won't rise/fall.

Since the 200V are the minimum rating, it should be OK to 70V.


Changelog:
-added diode name/diode model to the simulation
-added correct transistor model to the simulation

10
I finished the circuit for the unit.

Printing on the Board:

2000W Rated Power
input voltage DC24V- DC70V
maximum input current <48A
ZVS2000S High frequency induction heating
8300515

As far as I can tell, the controller checks for a mosfet fault before switching the relay on.
Voltage, current a temperature are always checked.
You can add an extra external switch for short heating applications.
There's a potentiometer to limit the max current.

The controller does NOT know if the circuit is oscillating or not, but you can check your setup with a low current setting. In case something went wrong, the unit should open the relay faster, that's handy before start working with different coils/voltages or after a repair for obvious reasons.

If the coil inductance is way too high/low, it can detect a mosfet fault.
The components with an "X" are unknown.

Due to the applied voltage of 100V, the mosfets, transistors, optocoupler and the resistor "R15" blew up. This resistor is crucial for the proper working. I have to wait for the new one board to get the value to repair it properly.
If I had removed the heat sink, the mosfets were most likely also got damaged and since there was no information available.
I wanted to know, how high I can get with the input voltage.

The measured current from the unit was way too high, I shortened the shunt and adjusted the value with some extra tin.
With that method you can also increase the maximum power output relative simple.

The optocoupler for the fan/pumpe is always on.

11
One approach could be a cheap steel pipe, weld a cover on the end and maybe use some of this coating.
The material costs are so small, if you have the welding stuff.

Keep in mind that using normal tools on really high quality stainless can ruin them.

I tested different pipe diameters and most of them easily reached the 2 kW power limit of my heater. The heater has a current and voltage sensor, so I can't go that high above the rating.
I can trick the unit by changing the components, but it's also nice to have a real power display without adding 50% or so on top.
I have a beefy 5kw adjustable unregulated power supply for 0-200V that comes handy, so it was no problem to get the highest possible power output with different shapes.

For example, I start with 30V with 1.5 kW then it rises up to the 2 kW and then it reaches curie temperature it goes down to 800W, and I turn the Voltage up to 60V and have my 2kw again.

These exact numbers depend on many things like the material, the coil, the geometry of the workpiece. Just some figures out of my mind, to get the point.
At the end of next week I can do some more tests.

If you use steel, you should really look the temperatures of the mosfets. I was able to get 50 A even at 30 V with good fitting steel tubes.

I think my coil has an inner diameter of 40 mm/ 1 5/8" something like that and 6 turns, runs with 157 kHz and uses an overall capacitance of 0,86 µF, which are rated for 100 A.

Robert

12
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

13
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

Pages: [1]

* Recent Topics and Posts

post Re: The new toy
[Laboratories ]
DashApple
Today at 08:17:36 PM
post Re: CM300 coil build questions
[Dual Resonant Solid State Tesla coils]
Mads Barnkob
Today at 08:06:32 PM
post Re: CM300 coil build questions
[Dual Resonant Solid State Tesla coils]
acobaugh
Today at 05:43:13 PM
post Re: Help choosing a Hantek USB oscilloscope
[Computers, Microcontrollers, Programmable Logic, Interfaces and Displays]
Twospoons
Today at 01:32:30 PM
post Re: Adventures in induction heating
[Electronic circuits]
Coyote
Today at 10:56:19 AM
post Re: Help choosing a Hantek USB oscilloscope
[Computers, Microcontrollers, Programmable Logic, Interfaces and Displays]
kamelryttarn
Today at 10:02:28 AM
post Re: CM300 coil build questions
[Dual Resonant Solid State Tesla coils]
davekni
Today at 07:05:19 AM
post Re: Help choosing a Hantek USB oscilloscope
[Computers, Microcontrollers, Programmable Logic, Interfaces and Displays]
Hydron
September 19, 2019, 11:16:21 PM
post Re: The new toy
[Laboratories ]
AlexanderHun
September 19, 2019, 09:49:30 PM
post Re: CM300 coil build questions
[Dual Resonant Solid State Tesla coils]
Mads Barnkob
September 19, 2019, 09:49:15 PM
post Re: The new toy
[Laboratories ]
Mads Barnkob
September 19, 2019, 09:13:29 PM
post Re: Help choosing a Hantek USB oscilloscope
[Computers, Microcontrollers, Programmable Logic, Interfaces and Displays]
Mads Barnkob
September 19, 2019, 09:08:20 PM
post Re: CM300 coil build questions
[Dual Resonant Solid State Tesla coils]
acobaugh
September 19, 2019, 07:16:20 PM
post Help choosing a Hantek USB oscilloscope
[Computers, Microcontrollers, Programmable Logic, Interfaces and Displays]
kamelryttarn
September 19, 2019, 04:19:58 PM
post The new toy
[Laboratories ]
AlexanderHun
September 19, 2019, 09:01:46 AM
post Re: CM300 coil build questions
[Dual Resonant Solid State Tesla coils]
acobaugh
September 18, 2019, 07:27:46 PM
post Re: CM300 coil build questions
[Dual Resonant Solid State Tesla coils]
acobaugh
September 18, 2019, 06:56:20 PM
post Re: CM300 coil build questions
[Dual Resonant Solid State Tesla coils]
acobaugh
September 18, 2019, 05:08:06 PM
post Re: CM300 coil build questions
[Dual Resonant Solid State Tesla coils]
Mads Barnkob
September 18, 2019, 01:35:58 PM
post Re: CM300 coil build questions
[Dual Resonant Solid State Tesla coils]
acobaugh
September 18, 2019, 05:54:23 AM
post Re: Blast from the past!
[Computers, Microcontrollers, Programmable Logic, Interfaces and Displays]
klugesmith
September 18, 2019, 05:05:55 AM
post Re: UD2.7 Gate Signals
[Dual Resonant Solid State Tesla coils]
coilinator
September 17, 2019, 08:24:59 PM
post Re: Blast from the past!
[Computers, Microcontrollers, Programmable Logic, Interfaces and Displays]
MRMILSTAR
September 17, 2019, 08:19:45 PM
post Re: Blast from the past!
[Computers, Microcontrollers, Programmable Logic, Interfaces and Displays]
Mads Barnkob
September 17, 2019, 06:53:52 PM
post Blast from the past!
[Computers, Microcontrollers, Programmable Logic, Interfaces and Displays]
MRMILSTAR
September 17, 2019, 05:52:00 PM
post Re: CM300 coil build questions
[Dual Resonant Solid State Tesla coils]
acobaugh
September 17, 2019, 05:00:47 PM
post Re: Welcome new members, come say hello and tell a little about yourself :)
[General chatting]
davekni
September 17, 2019, 06:48:38 AM
post Re: My second DRSSTC
[Dual Resonant Solid State Tesla coils]
erdal
September 16, 2019, 11:07:27 PM
post Re: 750W solar offgrid 24V/150Ah battery setup with Victron charger
[Electronic circuits]
johnf
September 16, 2019, 09:48:37 PM
post Re: adventures in homemade flyback bobbins.
[Transformer (ferrite core)]
AlexanderHun
September 16, 2019, 10:42:44 AM
post Re: Offgrid 48V solar to 24V battery setup
[Electronic circuits]
Mads Barnkob
September 16, 2019, 09:40:27 AM
post Re: My second DRSSTC
[Dual Resonant Solid State Tesla coils]
Mads Barnkob
September 16, 2019, 09:28:43 AM
post Re: Large Ferrite Core with IGBT-Brick Driver
[Transformer (ferrite core)]
Mads Barnkob
September 16, 2019, 09:24:17 AM
post Re: Help for people buying the "12-48 Volt 1800/2500 Watt ZVS induction Heater"
[Electronic circuits]
T3sl4co1l
September 16, 2019, 06:59:12 AM
post Re: Help for people buying the "12-48 Volt 1800/2500 Watt ZVS induction Heater"
[Electronic circuits]
davekni
September 16, 2019, 04:18:26 AM
post Re: My second DRSSTC
[Dual Resonant Solid State Tesla coils]
davekni
September 16, 2019, 02:49:28 AM
post Re: Large Ferrite Core with IGBT-Brick Driver
[Transformer (ferrite core)]
davekni
September 16, 2019, 02:43:18 AM
post Re: Homemade HV transformer
[Transformer (ferrite core)]
davekni
September 16, 2019, 02:36:17 AM
post Re: adventures in homemade flyback bobbins.
[Transformer (ferrite core)]
davekni
September 16, 2019, 02:26:40 AM
post Re: Help for people buying the "12-48 Volt 1800/2500 Watt ZVS induction Heater"
[Electronic circuits]
petespaco
September 16, 2019, 01:50:19 AM
post Re: UD2.7 Gate Signals
[Dual Resonant Solid State Tesla coils]
coilinator
September 15, 2019, 08:22:47 PM
post Re: My second DRSSTC
[Dual Resonant Solid State Tesla coils]
erdal
September 15, 2019, 02:09:17 PM
post Re: Homemade HV transformer
[Transformer (ferrite core)]
AlexanderHun
September 15, 2019, 10:39:29 AM
post Re: Homemade HV transformer
[Transformer (ferrite core)]
ElectroXa
September 14, 2019, 07:01:28 PM
post Re: adventures in homemade flyback bobbins.
[Transformer (ferrite core)]
AlexanderHun
September 14, 2019, 06:59:13 PM
post Re: Homemade HV transformer
[Transformer (ferrite core)]
AlexanderHun
September 14, 2019, 06:43:15 PM
post Re: Homemade HV transformer
[Transformer (ferrite core)]
ritaismyconscience
September 14, 2019, 06:35:32 PM
post Homemade HV transformer
[Transformer (ferrite core)]
AlexanderHun
September 14, 2019, 05:05:00 PM
post Re: UD2.7 Gate Signals
[Dual Resonant Solid State Tesla coils]
profdc9
September 14, 2019, 04:50:10 PM
post Re: UD2.7 Gate Signals
[Dual Resonant Solid State Tesla coils]
coilinator
September 14, 2019, 08:42:55 AM