Kaizer DRSSTC II

Introduction

I wanted to build a small DRSSTC in a few days without having prepared anything, most parts are reused or scrapped from things I have found and saved.

 

Safety

WARNING!: Working with electricity is dangerous, all information found on my site is for educational purpose and I accept no responsibility for others actions using the information found on this site.

Read this document about safety! http://www.pupman.com/safety.htm

 

Considerations

I was nervous that the metal enclosure for the driver was too close to the primary coil and would absorb some of the energy, first tests show no sign of heating of the metal.

I made the bridge section entirely on a normal one sided PCB and was not too sure if the traces were thick enough to withstand the high peak currents or keep a low inductance layout. It all seems to work without problems.

 

Specifications

  Revision 1 Revision 2
Bridge 2x G12N60C3D IGBTs in a half bridge configuration 2x IXGN60N60C2D1 IGBTs in a half bridge configuration
Bridge supply 0 – 160VAC through a variac, 6A rectifier bridge and 2x Aerovox 410uF 430V filtering capacitors in parallel.  0 – 210VAC
Primary coil Flat primary. Inner diameter 70 mm, Outer diameter 187,36 mm. 6 turns 1,78 mm copper wire (2,5 mm²), turn spacing 8 mm. Tapped at 4.8 turns.  
MMC 2 in series Cornell Dubilier (CDE) 942C20P15K-F capacitors for 0.075uF at 4000VDC rating.  
Secondary coil 50 mm diameter, 200 mm long, 1430 windings, 0,127 mm enamelled copper wire.  
Resonant frequency Around 327 kHz.  
Topload 40 x 215 mm aluminium tape on a Styrofoam toroid.  
Input power 250BPS, 250uS on-time, 68 primary cycles, 300A limiter: 120VAC in.  350BPS, 120uS on-time, 35 primary cycles, 280A limiter: 210 VAC in at 2A. 420 Watt.
Spark length Up to 240 mm long sparks.  Up to 370 mm long sparks.

 

Schematic

The driver is a variation of Steve Wards universal driver and beneath you can see the bridge schematics.

 

Construction

13th August 2011

Optimize driver PCB, design bridge PCB, toner transfer to PCB.

14th August 2011

Etch PCBs, assemble bridge PCB completely, half done with driver assembly. Heat sinks, electrolytic capacitors, voltage splitting capacitors and rectifier bridge are all salvaged components. Materials for building a enclosure and base is found. Lexan salvaged from LCD monitors is used for the base and some normal house wiring is used for the primary coil.

 

15th August 2011

Winding CTs for feedback and OCD, building enclosure and base, driver PCB assembled.

 

16th August 2011

Driver PCB fault finding and testing, enclosure and base building. I had forgot to add the trace that resets the OCD on the driver board after I moved it while optimizing the board layout.

 

17th August 2011

Complete construction and ran first test, no first light.

Some more detailed pictures of topload, secondary with terminations and primary coil.

Flat primary. Inner diameter 70 mm, Outer diameter 187,36 mm. 6 turns 1,78 mm copper wire (2,5 mm²), turn spacing 8 mm.

50 mm diameter, 200 mm long, 1430 windings, 0,127 mm enamelled copper wire.

40 x 215 mm aluminium tape on a Styrofoam toroid.

 

28th August 2011

First light, phasing of feedback transformer was wrong.

3rd September 2011

24 cm sparks, running 250uS, 68 primary cycles, 120VAC in, 268A primary current. 250BPS.

 

Here is a scope shot of the primary current waveform and a zoom of the same.

 

4th September 2011

I blew up both IGBT transistors running at the same settings as above on the 3rd September 2011, but at 160VAC input, nothing violent, just a flash and all was silent.

I will rebuild the bridge with IXYS IXGN60N60C2D1 IGBTs, which will hopefully make the bridge indestructible compared to the size of this Tesla coil.

11th September 2011

Rebuild the bridge and spent the day fault finding on the circuits as it did not work, turned out to be a 33V Zener diode on the bridge board that was short circuited.

 

16th September 2011

I recorded some data from different settings and came up with following before admitting that my heat sink is just too small. Further tuning is till needed, I hope it can do better and it seems to never go higher than 280A primary current.

I peak Voltage in, AC Current in, AC Burst length BPS Watt, AC Spark length, mm
280 210 0,5 120 200 105 274
280 210 0,75 120 300 157,5 290
280 210 2 120 350 420 354
280 210 4 120 500 840 370

200 BPS, 274 mm sparks.

 

350 BPS, 354 mm sparks.

 

500 BPS, 370 mm sparks.

 

Here is the current waveform which pretty much stayed the same doing these tests, also a better quality picture of the sparks.

 

Additional tuning gave me much better results in the form of almost the same spark output at lower on time, lower peak current and lower power in.

Here it is a screenshot of a spark going out to 337 mm running 70uS on-time, 260A peak current, 300 – 400 BPS at 260VAC at 0.5A.

 

Conclusion

Revision 1

It is no problem building a small DRSSTC in a few days with some previous knowledge and a off the shelf secondary coil.

In the future I will properly not make another Tesla coil with TO-247 IGBTs, I need some more overhead with the way I push my Tesla coils.

 

Demonstration

28th August 2011

First light

 

3rd September 2011

Came out a bit dark, but shows 24 cm sparks, running 250uS, 68 primary cycles, 120VAC in, 268A primary current. 250BPS.

 

16th September 2011

37 cm sparks, running 120uS, 35 primary cycles, 210VAC in, 280A primary current. 200 – 400 BPS.

 

16th September 2011

33,7 cm sparks, running 70uS, 260VAC in, 260A primary current. 300 – 400 BPS.

14th February 2012

Playing Doom 1 – Episode 1 soundtrack with my new midi modulator.

79 Responses to Kaizer DRSSTC II

  1. Pingback: Kaizer DRSSTC II – built, abused and broken | Kaizer Power Electronics

  2. Pingback: Kaizer DRSSTC II – upgraded and kicking! | Kaizer Power Electronics

  3. ben123324 says:

    hey, i want to build a similar coil using this driver, can you send me either schematics, eagle files, a board transparency, or all of the above? all i realy need is a black and white layout and a parts list, but i will take anything you can provide.
    thanks-
    ben

  4. Mads Barnkob says:

    Hey Ben,

    The driver is almost a copy of Steve Wards universal driver, you can find it on his website. The board layout is a constant improving work flow which currently have some hacks and bugs, so its not public.
    Stewe Ward got all you ask for online at his website, just google for it.

    Kind regards
    Mads

  5. Adam says:

    Nice work.

    Could you please explain your scope setup for the picture? Where you measuring? Differential and displaying a math trace.

  6. Mads Barnkob says:

    Hey Adam

    I am measuring primary current with a Pearson current monitor model 110. It is a 5000 A monitor giving a 0.1 V/A into 50 Ohm. My oscilloscope is adjusted so it shows 1V/A.

    Kind regards
    Mads

  7. Pingback: Kaizer DRSSTC II playing Doom 1 – Episode 1 | Kaizer Power Electronics

  8. 08Kutt says:

    mann, i have questions,
    which primary coil is the best for little DRSSTC’s? vertical, flat or conical? a feedback CT in secondary’s base is safe?
    thank youu!
    i have a small 35cm arcs drsstc but sometimes it go to fail :/

  9. Mads Barnkob says:

    Hey 08Kutt

    I would prefer the flat primary to get a greater distance between the topload and earth rail, you will likely get racing sparks from high coupling with a vertical primary and strikes from topload to the earth rail.

    I only use primary feedback as it provides feedback from the circuit that you control and you can run the inverter part without a secondary coil in, but use a dummy load of metal or water in a pan.

    Kind regards
    Mads

  10. Johan Garbøl says:

    GEEK!
    But very impressive tough…..

  11. 田中 says:

    Hello I’m Japanese.You can give me PCB Gate drive circuit,

  12. Mads Barnkob says:

    Hey 田中

    you can find all details and PCB layout here: http://stevehv.4hv.org/new_driver.html

    Kind regards
    Mads

  13. 田中 says:

    Thank you for reply.
    I will try with it.

  14. m griffin says:

    HI really nice set up,liking the sound on your new midi modulator,any chance you could forward me the schimatic,mine sound dire compared to yours!!
    thanks

    Markznsparkz

  15. Mads Barnkob says:

    Hey M Griffin

    I bought the midi controller from one of the guys on 4hv, I do not have the schematics or microcontroller code 🙂

    Kind regards
    Mads

  16. Dario says:

    Hi
    Can you please tell whitch type of ferrite core Can i use for feedback and ocd , is it need to be type 77 or Can i use cheap one from ebay?
    Thanks

  17. Mads Barnkob says:

    Hey Dario

    You can use type 77, just be sure to buy some with a permability over 4000. Avoid the cheap ones from ebay! I have also used N30 material with permability between 3900 to 6000. Just be sure to get some cores with a large enough cross section, then it should all work out great for you.

    Kind regards
    Mads

  18. Dario says:

    Thanks for repply.
    i am stil trying to get all components for building,so i was wondering i your opinion whitch IGBT would you pick for the setup of small DRSSTC ,secondary will be 90mm x 20-25 cm and powering from 240V , Bus capacitor 2200uf 450VDC i was thinking og IGBT brick IXGN60N60 but maybe it could go with smaller one?
    You preffer flat primary or?
    Thanks
    Dario

  19. Mads Barnkob says:

    Hey Dario

    Use the IXGN60N60 so that you have some head room, it is the most fun when it is not the electronics that is the limit to spark length, but the floor and ceiling 😉

    I prefer flat, not as tight coupling and it is further away from the topload, fewer strikes close to the primary, you could also avoid raising sparks with the lower coupling.

    Kind regards
    Mads

  20. Dario says:

    Hi Mads
    i found 500T600-3E2A ferrite that i used for old project i think they will be ok for GDT and feedback,ocd ..,only i am not surre is the center hole 25mm to big for cable 10-16 mm2 since is small DRSSTC otherwise please comment the core.
    Thanks
    Dario

  21. Mads Barnkob says:

    Hey Dario

    The cores seems to be rated for 5000u, which is sufficient.

    The center hole is not too big, it will be fine and you have some space for extra insulation.

    Kind regards
    Mads

  22. ILoveStorms says:

    Can i use those capacitors? 940C20P22KF
    Can i use those too? MKP1845422104 (With this second one i will be able to make a bigger – better MMC )
    Can i use this instead of the universal driver
    http://www.fineartradiography.com/hobbies/high%20voltage/dsdrsstcdiag.jpg
    With those IGBTs FGH60N60SMD (They are really cheap here)
    Would this core work for the GDT of this coil? EPCOS — B64290L674X830

  23. ILoveStorms says:

    941C20P68K-F

    This has very high peak currents! I bet those would work best
    Am i right?

  24. Mads Barnkob says:

    Hi ILoveStorms

    For a small DRSSTC like this you can use almost any polypropylene switching capacitor with dv/dt around 1000 and 250-500Apeak, or even less if you can accept some losses in the tank capacitor. The 940C/941C are virtually identical and the MKP is the worst of those three. Consider then 942C series as those capacitors are thoroughly tested in DRSSTCs.

    I advise you on using the universal driver to have over-current detection, without it you risk blowing up those IGBTs. They are only rated for 180Apulsed and will likely blow up if you push them beyond 300-400A.

    The Epcos ring core is fine.

    I suggest that you figure out your primary current that you want to run, look at other coils people have made and work out from those figures. The choose a IGBT that can actually run at those peak currents, use a driver with over-current detection to protect your IGBTs from failure. Use my MMC calculator to make a MMC with voltage, peak current and rms current ratings that can withstand your design.

    Kind regards
    Mads

  25. ILoveStorms says:

    Hey. Those igbts would work then! FGH75N60UF (I’ve read about them being pushed to 450A pulsed)
    And.. Do you have any eagle files for the UD? Also. Can you estimate a cost of the full UD?
    Can the entire thing ( Half bridge , Control circuit ) be fitted in a single board that won’t look ridiculous against the 4 inch wide , 4 inch long mini coil?

  26. Mads Barnkob says:

    Hey ILoveStorms

    I only have ExpressPCB board files for single sided board, not currently public. The parts for UD1.3 driver, without opto receiver is around 14 Euro, that price is when I bought parts for 20 drivers.

    I see no reason why you should not be able to get it all on a two 4×4″ board, have them on top of each other to save foot print, you just have to spend some nights routing till it fits.

    Kind regards
    Mads

  27. ILoveStorms says:

    One final question.
    It gets me wondering. How is the interrupter connected to the actual control circuit?
    On a side note. What do you think of the IGBT i linked to last post? It seemed to be enough
    On an unrelated side note. Happy christmas
    On a completely unrelated side note. 365 days ago. The world ended
    Happy holidays

  28. Mads Barnkob says:

    The interrupter output goes into a opto transmitter, through a optic fibre wire and into the opto receiver on the driver. This insures total isolation between the Tesla coil and the user holding the interrupter in the hand.

    If you have experience from others that have pushed those to around 500A, they should be fine, as you can see this little DRSSTC runs at about 300A.

    Merry Christmas 🙂

  29. ILoveStorms says:

    How can I do it with RCA cable?
    I am too poor for fibre optic cablez

  30. ILoveStorms says:

    The signal goes directly into pin 5 of the 74HC14 and the signal ground.. Into ground
    And isn’t the UD too complicated for for the tiny coil I am willing to make? Also I am thinking about using this Igbt http://docs-europe.electrocomponents.com/webdocs/0dd2/0900766b80dd2e65.pdf
    For it’s higher current capabilities.. It does not seem to have an internal diode thought

  31. Mads Barnkob says:

    Directly as with any other wire and use the screen as ground. Nothing special there.

  32. Mads Barnkob says:

    Correct, if you do not need the interrupter signal inverted, skip the first hex-inverter gate, it is only there because Ward used a opto receiver that inverted the signal.

    When you switch currents of these magnitudes, you want control in order to protect your components, if you go for a simpler circuit, you also loose control and accept the increased risk of blowing up your IGBTs.

    The SOT-227 IGBT die sizes are about the same as the TO-247 so they only have slightly better ratings and does not handle currents much over their Icm rating as the increased Icm rating is due to the larger heat sink foot print. Go for a maximum of 500Apeak with that IGBT.

    You can just add external ultra-fast diodes when there are no internal diodes.

    Kind regards
    Mads

  33. ILoveStorms says:

    I was thinking of using this. http://docs-europe.electrocomponents.com/webdocs/0fe4/0900766b80fe4838.pdf
    Along with two 1 UF 940C 2000V 700 amp peak caps. I am thinking about changing the coil’s dimensions. 4 inch wide. 7 inch long with 34 AWG . The only other pipes i have are 10 inch wide. Which is too big. Can’t current protection be in the form of a fuse? And is there no simpler circuit with OCP ( Over current protection )

  34. markznsparkz says:

    To ILoveStorms
    it might be werth you looking at the onetesla design there was someone on ebay selling the PCB for £20 i made one from this and they work very well with minimal effort in building ,mine can produce a good 2ft arc with steve wards interupter,but like it has been said a coil that is too short will just arc out to ground or worse to the primary blowing the power out,the main thing you need to know when tunning it is to make the primary lower in frequency than the secondery as the secondery frequency will drop as the arcs are formed the longer the arc the more the frequency drop.mine has about 15 to 20 % drop at full power,i blew a lot of igbts untill i worked this out.

    http://onetesla.com/

    here is a video of mine.

    http://www.youtube.com/watch?v=YKd7rl0bQps

    it gives basic dimetions under video

  35. Mads Barnkob says:

    So far you went from using a Icm 180A TO-247 IGBT to a half bridge module.

    Your idea of using only two capacitors is simply inadequate to such a bridge size.

    The secondary coil is in my opinion too short and you will regret trying to wind such a thin wire.

    There is no way you can use a fuse to catch a over-current 100A larger than 500A when the burst last for 200uS.

    If you want a simpler driver, make a hybrid between the simple dual driver antenna feedback driver and Wards UD1.3. But as I said earlier, it is a compromise between cost, complexity and willingness to risk blowing stuff up.

    I think you should replicate the dimensions of a existing DRSSTC and learn your way around it, you have many basic questions that show you do not fully understand the mysterious ways of amateur coiling, I am no expert, but I learned it slowly and by trying what others did first, just like you learn anything in school. There is no short cuts, there is no simple or cheap way to reliably make long sparks.

    If something is worth doing, it is worth doing right.

  36. ILoveStorms says:

    I usually point the break out point up.
    On the one tesla site. In the downloads section.. When i try to download the eagle files it gives me 404 Not Found.. And i think a strike rail would fix that problem :). By the way. Your coil looks amazing :D. A spun topload would make it look perfect.

    Mads
    Have a peek at this http://www.loneoceans.com/labs/drsstc1/
    It uses 36 AWG wire.
    I already have a hard time winding 34AWG wire.
    So i re-adjusted the secondary coil to my liking.
    Measured in inches

    Diameter : 4
    Length : 10
    Turns : 1587
    AWG : 34
    Toroid : 10 inch major diameter , 3 inch minor diameter

    Primary:
    Form diameter : 6
    Form height : 1.6
    Turns : 3.1
    AWG : 12 (Wikipedia says it has a rating of 5.3 KA for 32 MS)

    What JAVATC spat at me when i gave it the values
    http://i1331.photobucket.com/albums/w591/grim3322/output_zpsc6a4ee28.jpg
    The IGBTs will be the FGH75N60UF
    And two 1 UF 2KV caps in series
    Thank you
    Merry christmas!

  37. markznsparkz says:

    you can get the onetesla eagle files from here.
    http://isopack.blogspot.co.uk/2012/05/onetesla.html

    if you still have problems i can send you a copy on email.

    toploades are way out of my price range but i do agree it would look better and proberbly get a slightly longer arc.

    you don`t want to let the arc hit a strike rail or any earth if it can be helped ,strike rails are only there to stop the arc from hitting the primary but in hitting the rail or another earth i causes the current in the primary to go up and can blow the igbts this is why the more elaboate coils have current limiters that wind back the interupter input as soon as it detects a over rise in the current which is set by the user.

  38. ILoveStorms says:

    A quick search on google got me the schematics for 220V
    But. They seem to be shorted O.O http://i1331.photobucket.com/albums/w591/grim3322/Weirdboard_zpsbda40c0a.jpg
    As you can see the main power traces are shorted o.o.. Also the positive lead on the upper capacitor is left unconnected? Same for the negative lead of the bottom capacitor. And two diodes are left unconnected O.O…. And traces from the control circuits intersect with traces from the H-Bridge. The middle pin of the IGBT is left untouched. And what are those dots all around the bridge?

  39. markznsparkz says:

    this is only showing half the board the high voltage side all the control chips and drivers are to the left (not seen in picture)the dots is the copper track on the other side that carries the main power from the 1000uf caps to the igbts.the diodes are connected on the other side.look at the 220v schimatic on the onetesla site.

  40. markznsparkz says:

    here is the ebay seller that is selling the boards ready made even cheaper than when i had one.

    http://www.ebay.co.uk/itm/10-Musical-Tesla-Coil-Printed-Circuit-Board-/121240438778?pt=LH_DefaultDomain_3&hash=item1c3a7e47fa

  41. ILoveStorms says:

    I am talking about the board files not the schematics. And that picture was something i snipped off the real board files which i have. And is the one tesla board a double sided board? It does not seem to be so

  42. ILoveStorms says:

    Mark , I do not like buying pre-made boards

  43. markznsparkz says:

    yes the onetesla board is double sided

  44. ILoveStorms says:

    Oh.. I ‘ve never made double sided boards before.. Where are the eagle files for the other side?

  45. Mads Barnkob says:

    The OneTesla is such a simple schematic, you could have drawn your own single sided board by now in ExpressPCB, laser printed, toner transferred, etched and start soldering 🙂

  46. ILoveStorms says:

    Indeed mads 😀
    But what do you think of the dimensions I gave you above

  47. Mads Barnkob says:

    155 kHz is a good low resonant frequency, the IGBT module is properly over kill compared to the energy transfer possible to the secondary, but then again, you wont blow it up.

    Take a look at your coupling, it is much higher than suggested by JAVATC and for a DRSSTC you do not want a higher coupling than the suggested, the peak current is high enough for transferring the energy and with a too tight coupling you risk racing sparks or flash over. You could also consider making a pan cake coil instead of the helical, pan cake coils have lower coupling.

    I still think you should invest more money in your MMC, did you plot the numbers into my MMC calculator to see if you are within live driving conditions in regard to voltage rating, peak and rms current rating?

    I still think you should use UD1.3 with a proper primary current feedback and over current protection. The antenna feedback and no protection is asking for trouble 😉

    Kind regards
    Mads

  48. ILoveStorms says:

    I totally forgot the MMC calculator! (Stupid me)
    Throwing the MMC i was planning for at it gave me unsatisfying results. So i redesigned it! The new MMC will sport 4 of those http://www.farnell.com/datasheets/621879.pdf (2KV .68UF ones)
    2 in series and 2 in parallel
    (That is for 300 peak amps and 200 US and 200 BPS)
    The capacitor’s capability is 1026A
    The calculator says that the RMS currents will be 30A , The capacitor’s capability is 31.6 Amps
    Seems enough 🙂
    The FGH75N60UF are not modules. But they seem enough. (They are TO-247)

    A pancake primary.. I might consider it. But i though it was a very good idea to put a large tube (Maybe 4.5 or 5 inches)
    and then wind the primary on it.
    The one tesla schematic is not based on antenna feedback. It seems to have a current transformer
    My reply to no protection is using parts that are more than capable of doing the job. Remember. It is a small DRSSTC just for testing and gaining knowledge i lack
    Also i will go for the double sided PCB. As i want to know how to make those ( I will most probably need it when i try to make the UD)

    And..
    A very merry christmas to you!

  49. Mads Barnkob says:

    Looks good on the specifications so far, as the peak currents are still relatively small in a DRSSTC scale, it should do fine and the MMC only experience a little heating on long run times. Does it also withstand the voltage? We are already using their DC voltage rating as AC voltage rating, so do not have a MMC without voltage head margin.

    Have fun building your Tesla coil and I look forward to see it running 🙂

    Kind regards
    Mads

  50. ILoveStorms says:

    The coil will only get 220VAC in. That was about 300-310 VDC.. So it seems enough.
    Also i decided on this IGBT http://docs-europe.electrocomponents.com/webdocs/122f/0900766b8122f8a9.pdf
    It has a pulsed current greater than 300A. The difference in switching time is not huge , It uses newer technology AND I do not like pushing anything beyond it’s rating Also i have a Boomophobia (LOL)
    I will begin construction in january.
    Wish me luck!
    Merry christmas

  51. Mads Barnkob says:

    The voltage over the MMC have nothing to do with the input voltage, but the MMC impedance times the primary peak current. Look at the formulas beneath the MMC calculator and try to play around a little with the peak current in the calculator, remember to enter the correct specifications for the capacitor you are using.

  52. ILoveStorms says:

    I did. And i came up with something. Entering the specifications of my capacitors and coil. I found that the results would be much better if all the 4 capacitors would be in parallel
    That would reduce primary impedance and the peak currents for the capacitors would be ~2000 amps. And at 200 US On time and 200 BPS. It would take 63 amps of RMS currents. RMS currents are about 50 if the peak currents are 500 AMPs ( My tiny coil will probably never get close to that)
    4 capacitors in parallel then.

    Also i though of an idea for a toroid :o. Its similar to Eric goodchild’s largest DRSSTC. Basically i have a ton of 3mm thick zinc coated aluminum wire. Now imagine 4 wood circles each with a diameter of 3.25 inches. Each two will be epoxied to two ends of a wooden stick. So now we have two wooden stick each with a wooden circle on each side. Now we epoxy the sticks together taking care that all the circles are vertical. And then i would drill holes 3mm wide all 360 degrees (Taking care they are atleast 1mm apart. ) And then i would insert the wire Into the holes of all the circles which would form a kind of spiral / winding. The distance of 1mm between wires would make that toroid have a good capacitance. And a wire can be soldered ( From the inside) to connect the beginning and the ending of the coil to cancel the inductance.
    What do you think? In my imagination the toroid looks amazing 😀

  53. Mads Barnkob says:

    The idea of making a toroid topload from wire is far from new, chicken fence was used by some of the old pioneers when making large toroids.

    Try simulating in JAVATC a toroid the size you want to make the toroid and then try with maybe 7 or 9 rings around the outer 180 degrees of the circle. You will see that the capacitance is almost identical, you do not need to have the wires so close and all 360 degrees around, the inside can be omitted.

    The holes you wanted to drill in the circles, make them slits instead where you can insert the wire from the outside and not pull it through, if you have to pull it through 4×15 holes it will look horrible and take forever to do 🙂

    Kind regards
    Mads

  54. ILoveStorms says:

    The rings must be connected though otherwise they will just arc to each other.. Also the wire.. Is just a wire. Not a tube like they used in that monster DRSSTC. And only 7 rings of the 3mm
    wire would look really empty with a topload that is supposed to be 3 inches high. I eventually though of the idea of the slits though. And pulling the wire through the hole also did not seem like a really good idea 😛

    Also i lack an Oscilloscope so calculations are really my only real way to figure frequencies etc. 🙁

  55. Mads Barnkob says:

    Of course they will have to be connected. What I am saying is that there is no reason, besides purely cosmetic, to add enough rings for it look like a complete toroid as the capacitance of a smooth toroid and one made out of 7 rings is almost identical.

    As long as you put in good, verified numbers in JAVATC, the results you get there are very close to reality.

    On a note of pulling wire through holes, that is how I made the Kaizer DRSSTC 1, pulling 8 rings of a helical coil of 10 mm copper tubing through 4 holders. That was a pain, took a lot of oil, hitting, hours and twisting to get it in position, I will never repeat that or advise anyone on trying that. Waste of time.

    Kind regards
    Mads

  56. ILoveStorms says:

    Exactly. I want the coil to look good.. Cosmetics 🙂
    Pulling wire through holes.. Oil and hitting? Thank you for your advice.. 🙂
    Thank you mads 🙂

  57. Arvin says:

    hi i’m arvin please help me how to calculating c3 10uf 400v and why you use it tanks
    Merry christmas

  58. Mads Barnkob says:

    Hello Arvin

    C3 is a snubber capacitor to protect the IGBT switches. If you want to calculate its value, search on the internet for IGBT snubber design. As a general rule you can also just use somewhere between 1 to 10 uF, voltage rating higher than your supply voltage to the bridge. The capacitor have to be a snubber capacitor or other pulse rated metallized film capacitors.

    Kind regards
    Mads

  59. Arvin says:

    Hello Mads Tanks for helping me.and can i use TVS 1.5KE440CA for IXGK60N60CD1 or 1.5KE350CA for IRFP460&IRFPS37N50A

  60. Mads Barnkob says:

    Hey Arvin

    Choose the TVS so that enough in series protects the switch from voltage spikes of a higher voltage than their rating. F.ex. use two 440 volt TVS for protecting a 600 volt IGBT.

    Kind regards
    Mads

  61. Arvin says:

    Hi Mads

    Two 440V TVS in series, wouldn’t kill spikes the IGBT(600V) before it clamp by the TVS (880V) ?

  62. Mads Barnkob says:

    Hey Arvin

    The TVS, together with the snubber capacitor C3, forms a protective network for the IGBTs. Short spikes does not have the energy to destroy the IGBT so hard clamping is not needed before it is getting real serious. C3 will also take care of some of the spikes.

    Kind regards
    Mads

  63. Arvin says:

    Thanks for helping

  64. Dario says:

    Hi Mads
    i hope you can help me again.After a while i decided te test my UD 1.3 driver like you did, i used signal generator to test OCD and it is working but one thing is not going i can’t get interrupter led flashing. Interrupter i used is one from oneTesla midi/fixed and hfbr1412. the diode in hfbr1412 is on but you can barely see it and when i connect fiber to it on other end of fiber i cant see nothing so i used my phone camera and there is some light but i am not shure if it is enough.On the hfbr2412 output there is nothing.
    thanks
    Dario

  65. Mads Barnkob says:

    Hello Dario.

    Steve used a opto receiver that inverted the signal. So be sure that you are sending the same kind of signal as you expect to receive at the driver. Maybe the battery for the interrupter is too low?
    Kind regards
    Mads

  66. Dario says:

    Is it possible that problem is that Ward use OPF2412T OR HFBR2412T and i have HFBR2412TZ??
    Thanks

  67. Mads Barnkob says:

    Hey Dario

    The three receivers your listed are the exact same circuit, if you look at the datasheet, the Z indicates that the part is RoHS compliant, so nothing to do with operation.

    Remember that the interrupter sends a, perhaps, 120Hz signal at 200uS, this is a very short pulse and will look very faint when you look at the fiber cable, so it sounds like it is fine.
    The problem must be at your receiver.
    I removed that interrupter LED from the UD1.3, it gave me some problems, maybe you are having the same problems?

    Kind regards
    Mads

  68. Dario says:

    Hi Mads
    since i must wait for parts to repair fiber optic i dicided to go on with my 60n60 halfbridge.
    90% is done (gdt,tvs,screw terminals…) i made pcb in eagle similar to easternvoltage one.
    I noticed that you and others are using this two capacitors (voltage devider) for bridge.
    Why is this sistem better than connecting it direct no negativ rail without 2 cap.??
    Do you suggest i do the same or should i go direct to negative.??
    I wont be using doubler since i have main 220ac.

    Thanks
    Dario

  69. Mads Barnkob says:

    Hey Dario

    When switching a inductive load with a half bridge, there will be some heavy back emf from the load. The capacitors help filter these low order harmonics out from interfering the DC bus voltage, the voltage could have sudden transients that in worst case would destroy the switching devices.
    The supply voltage is however half of the input voltage, which is why you often see better performance when using full bridges that switch the full voltage.
    You can try to tie the load directly to the negative rail and do all you can to protect the transistors from transients.

    I look forward to hear about your progress and experiences.

    Kind regards
    Mads

  70. Dario says:

    Thanks for explanation
    but then is very important that this two cap’s are not only mpk they must also be same quality as mmc because of peak current??
    The qualitty of them can also improve the output of Coil?
    In your project you use 1uf MPK but i also saw people use the well known CornelDoubillier 0.15uf/0.33uf 2000VDC,the same like MMC.
    Dario

  71. Mads Barnkob says:

    Hey Dario

    The voltage divider capacitors only sees the current being drawn from the DC supply, not the peak currents that float in the primary circuit between primary coil and tank capacitor. So you can use either one.

    As long as you use polypropylene capacitors with a low ESR it would properly be that best bet, a high dv/dt rating will also indicate that they can deliver energy fast.

    Kind regards
    Mads

  72. Ray says:

    Hi Mads,

    I’m wondering how you determine the phase of the current transformers and how you change the phase. Do you just reverse the leads from the current transformers ?

  73. Mads Barnkob says:

    Hey Ray

    You just have to try it one way or the other. You can either turn the transformer 180 degrees or reverse the leads going to the driver board.

    Kind regards
    Mads

  74. Ray says:

    Hi Mads,

    Thanks for the quick reply. Does the phase of the OCD current transformer matter ? Or can it be used both ways and only the phase of the feedback transformer matters.

    Thanks,
    Ray

  75. Mads Barnkob says:

    Hello Ray

    As the input from the OCD CT is rectified to a DC positive level voltage, it does not matter what phasing it has.

    The OCD circuit will only disable from the next cycle and not the current one triggering the OCD, so even if it is phase shifted it will still be tripped for the next cycle.

    Kind regards
    Mads

  76. paul says:

    Hey Mads,
    How many winings has your primiary Feedback and the OCD?

  77. Mads Barnkob says:

    Hey Paul

    I use cascaded current transformers for both feedback and OCD, they are both the same, it consists of two cores with 33 windings on each and one winding going through the second to get a ratio of 33:33:1.

    It is the same as a 1:1089 ratio current transformer, just so much easier to wind by hand.

    Kind regards
    Mads

  78. Diego Garcia Contreras says:

    hi
    I am making your model Tesla coil, but I have several factors which give me a spark of about 2-3 cm away; I’d like to orientaras in siguuientes questions:
     
    the secondary coil is of 26 gauge copper wire: .4mm in diameter, which is coiled to a PVC tube 4 inches and height of the tube is 1.10 meters, so that 1750 turns have.

    in the primary coil is not that caliber copper put, also the number of turns I have to do for this; distania between each of the laps.

    handling a voltage of 110 volts, that factor I think is important but I’m not so confident to increase to 220 by So please help.

    that often I can and I have to make it work?

    to make the small winding (the terminal named A -A, -B B, C -C, and -D D terminal is directed to the primary coil) so do 15 laps, this is correct or advice me das?

     that way I can increase the beam pulling the coil?

  79. Pingback: MIDI modulator for DRSSTCs | Kaizer Power Electronics

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