Recent Posts

Pages: [1] 2 3 ... 10
1
Solid state Tesla coils / Re: SSTC Not Working Correctly
« Last post by Laci on October 19, 2017, 10:41:14 PM »
This evening I ordered 4xIGZ100N65H5XKSA1 IGBT,calculated the maximum switching time which is around 800kHz so the switching should not be problem.Also bought some 74HC109N's to maybe upgrade to DRSSTC,if it will work as SSTC ;D
I will look for the type of varnish you said,and hopefully I can make the job.
2
Solid state Tesla coils / Re: SSTC Not Working Correctly
« Last post by Mads Barnkob on October 19, 2017, 08:31:02 PM »
Try to look for a clear non-coloured polyurethane varnish, I have used some that was meant for boats or floors, just be sure it does not contain oil, some for boats does that and it has problems hardening up completely when there is nothing to absorb the oil (it properly would if it was used on wood). You should be able to find polyurethane varnish in all home improvement stores and paint stores.

I would like to use epoxy, but that is hard to come by in Denmark.
3
Solid state Tesla coils / Re: SSTC Not Working Correctly
« Last post by Laci on October 19, 2017, 07:48:03 PM »
I made a driver,with PLL halfbridge(irfz44),running everything on 12V,so I can tune the frequency and measure it.At a range of 150-160kHz,a fluorescent lamp is lighted up at almost  max. brightness,current drawn is at around 0.1-0.2A at 5+ primary turns and under that the current increases rapidly and does not increases the output power.I did not expected anyting better than this,because the setup was just made in order to check the secondary's resonant frequency.
The feedback for the PLL is also working,it adjusts frequencies as even high as 180kHz down to the resonant frequency (150-160kHz).

The previous slayer exciter test loaded the 55v PSU to 50V,so that was not the problem.Even if I shorted the collector to the + rail,no current was flowing,so I think that the 47k base resistor was too big.In this case without a signal from the base of the coil,the transistor never turns on,and with less turns,the induced current into the secondary coil is not big enough,to trigger the transistor I THINK... :o

My new question is how and what kind of varnish can I use to insulate the secondary coil?I visited some nearly electronics and hardware  stores and nowhere could I find varnish for magnet wire.I have nitro based laquer,but I do not know if I can use it for this or not.Actually I want to protect the coil,and prevent the pretty lose windings from overlapping,not to prevent it from too high voltage. :D
4
Smart phones / Re: Sony Xperia ZX Premium (960FPS / 720p / 5 seconds)
« Last post by Mads Barnkob on October 19, 2017, 07:37:49 PM »
I gave up completely on trying to capture a capacitor discharge into a copper wire, since the intense light of the explosion completely blinds the camera as it has no time to adjust ISO and shutter speed in time, so what you get is a lot of frames that are completely white, useless :(

It is only a toy for recording different every day happenings and enjoy the little things in slow motion, as the next two videos show. Jumping kids in slow motion is however also a good way to spend time with them :)

/>
5
Solid state Tesla coils / Re: SSTC Not Working Correctly
« Last post by Mads Barnkob on October 19, 2017, 09:22:56 AM »
Laci: Could you also measure your power supply voltage for these experiments, because I think that you are loading that down so much that its voltage drops a lot and that is why you have no output.

Lets look at some parameters on the different IGBTs

IGBTVce____Vce(sat)125CmaxIcm____Gate charge___Combined switching time___Switchng losses
HGTG30N60A4600 V2 V240 A300 nC225 ns1 mJ
IRGP50B60PD1600 V3.6 V150 A250 nC180 ns1.25 mJ
IGW60N60H3600 V2.2 V180 A375 nC350 ns3.5 mJ
IGZ100N65H5XKSA1650 V1.9 V400 A210 nC480 ns2 mJ

Vce(sat) is the voltage drop across the IGBT and the conduction losses are equal to Ohms law, so if this is 2 V and you have 100 A, 200 Watt losses, there is ofcause some derating in the link below that can be done due to short on-times. The lower Vce(sat), the better.

Icm is a good measure on hard you can push the coil, how much current you can conduct in the primary circuit.

Gate charge is a figure for the energy needed to turn the IGBT on, but also the same amount that has to be drained when turning it off, the large number, the better driver is needed.

Combined switching time is how fast you can switch the current on and off, the lower number, the high frequency is possible, for more details see here: http://kaizerpowerelectronics.dk/tesla-coils/drsstc-design-guide/igbts/

Switching losses is also very important, here you have to calculate how much power you have to dissipate from the IGBT to the cooling system (heat sink, water cooling, etc) in order to keep the die temperature rise within a acceptable limit, again see the above link for details.

IGZ100N65H5XKSA1 does indeed look very good, so does the others, but not IRGP50B60PD1, it has a too high Vce(sat). They will all be able to switch up to 300-1000 kHz(Fmax1), the limit you have to find is the power dissipation(Fmax2) to keep temperature rise within your design goal.
6
Solid state Tesla coils / Re: SSTC Not Working Correctly
« Last post by Laci on October 18, 2017, 09:26:42 PM »
I'm also planning to buy some IGBT's.
I've seen which ones are good for tesla coils so I have a collection to choose:
HGTG30N60A4
IRGP50B60PD1
IGW60N60H3
and IGZ100N65H5XKSA1 which have very promising properties of 650V,100A,500W+,but I don't know its switching speed.

Which IGBT would be the best at >150kHz frequency in full bridge  configuration?
7
Solid state Tesla coils / Re: SSTC Not Working Correctly
« Last post by Laci on October 18, 2017, 08:14:54 PM »
So I made some measurements.The resonant frequency is 140kHz i think,but i'm not sure,because every frequency was measured with multimeter.The power supply is around 55 volts,large smoothing capacitor.
•Without topload:3 turns primary,current is 1A,and it outputs around 0.5cm arcs and they are pretty weak,can't pull a constant arc.With more primary turns,current drops,but the arcs gets more powerful,around 2cm.
•With topload <5 turns does not give any output,and by increasing the primary turns the current is dropping,arcs are increasing-the same thing as without topload,but the arcs are not as big as without topload,seems like it needs more primary turns with topload to work better.
The frequencies are pretty high(around 400kHz) in both cases,measured with multimeter so i think it's not accurate or it's not measuring what it should.

Also,the height of the coil is 50cm,a bit taller then I described,because I wound it until I ran out of magnet wire.
8
Solid state Tesla coils / Re: SSTC Not Working Correctly
« Last post by Mads Barnkob on October 18, 2017, 08:00:24 PM »
Mads: Secondary Q depends mostly on arc loading, so it is probably much lower than that calculated from wire gauge and skin effects.

I don't quite understand your remark on loading down the slayer exciter. I'm not familiar with that circuit. How do you load it down aside from blowing up the transistor or overloading the power source?

Yes I was using unloaded figures here

From what I understand, the slayer exciter circuit is quite simple and not a big power pusher, that from its feedback oscillating nature has a narrow performance and can not keep up with feeding a larger capacitance, but I could be wrong :)

I recall back when I build SSTCs that larger toploads always meant trouble, but it could be as you describe that the higher primary currents was the real culprit causing flashovers as I caught on video at 3:37:

9
Solid state Tesla coils / Re: SSTC Not Working Correctly
« Last post by Uspring on October 18, 2017, 10:46:42 AM »
Laci: You're right about the tuning not being dependent on the primary turns. I'd expect a larger primary current with with less primary turns, which might increase power throughput. The important term here is amp turns, which probably increases with less turns.
Adding a top load decreases secondary resonance frequency, which will also increase primary current, since primary impedance becomes lower with a lower running frequency.

The feedback will not always have the coil run at exactly the secondary resonance frequency. The condition for a working feedback is a 0 degree phase shift all over the feedback loop. I don't know, what your circuit looks like, but imagine, that the switching transistor is driven by an antenna. Then remove the antenna and replace it with a signal generator at exactly the same frequency, that the coil is running when using an antenna. The coil will behave as before and the antenna (now unconnected) will deliver the same frequency and phase as the signal generator. That shows, that the whole system phase shift between driver input and antenna output is 0 degrees.

The 0 degree condition is likely near the secondary resonance frequency, since the "whole system phase" varies strongly with frequency near resonance and the chance is high, that there is a frequency, that matches the 0 degree condition. That frequency might not be the best one for maximum power transfer between primary and secondary.

It's difficult to explain your observations without knowing the specs of your coil, e.g. feedback circuitry, inductances, capacitances coupling and such. You might try running a simulation.

Mads: Secondary Q depends mostly on arc loading, so it is probably much lower than that calculated from wire gauge and skin effects.

I don't quite understand your remark on loading down the slayer exciter. I'm not familiar with that circuit. How do you load it down aside from blowing up the transistor or overloading the power source?
10
Solid state Tesla coils / Re: SSTC Not Working Correctly
« Last post by Mads Barnkob on October 18, 2017, 10:07:11 AM »
Uspring: So I was wrong about saying high impedance would be better, as that is quite opposite of a larger gauge secondary wire which would give a higher Q, also be able to carry more current etc.

I think my SSTC2 is around Q~140 and that is much higher than a conservative estimate of k=0.2, so that 140 > 50. That could also blow the MOSFETs when pushing out almost 500mm sparks :)

I only had a old analog oscilloscope back then, so that would be a good experiment for the future, so get it back out and hook it up to DSO, CT and Diff. probe.

Laci: A topload will represent a much bigger load to the energy source on the primary circuit, I think you are simply loading down the slayer exciter. So when you add more primary turns with the topload on, it is not as high currents flowing and it has a chance to actually deliver power to the secondary circuit.

Can you measure what resonant frequency it was running at, in the different setups?
Pages: [1] 2 3 ... 10

* Recent Topics and Posts

post Re: SSTC Not Working Correctly
[Solid state Tesla coils]
Laci
October 19, 2017, 10:41:14 PM
post Re: SSTC Not Working Correctly
[Solid state Tesla coils]
Mads Barnkob
October 19, 2017, 08:31:02 PM
post Re: SSTC Not Working Correctly
[Solid state Tesla coils]
Laci
October 19, 2017, 07:48:03 PM
post Re: Sony Xperia ZX Premium (960FPS / 720p / 5 seconds)
[Smart phones]
Mads Barnkob
October 19, 2017, 07:37:49 PM
post Re: SSTC Not Working Correctly
[Solid state Tesla coils]
Mads Barnkob
October 19, 2017, 09:22:56 AM
post Re: SSTC Not Working Correctly
[Solid state Tesla coils]
Laci
October 18, 2017, 09:26:42 PM
post Re: SSTC Not Working Correctly
[Solid state Tesla coils]
Laci
October 18, 2017, 08:14:54 PM
post Re: SSTC Not Working Correctly
[Solid state Tesla coils]
Mads Barnkob
October 18, 2017, 08:00:24 PM
post Re: SSTC Not Working Correctly
[Solid state Tesla coils]
Uspring
October 18, 2017, 10:46:42 AM
post Re: SSTC Not Working Correctly
[Solid state Tesla coils]
Mads Barnkob
October 18, 2017, 10:07:11 AM
post Re: SSTC Not Working Correctly
[Solid state Tesla coils]
Laci
October 16, 2017, 09:34:16 PM
post Re: SSTC Not Working Correctly
[Solid state Tesla coils]
Uspring
October 16, 2017, 01:28:56 PM
post Re: Counter Poise Grounding for Tesla Coils
[Dual Resonant Solid State Tesla coils]
Mads Barnkob
October 16, 2017, 09:32:08 AM
post Re: SSTC Not Working Correctly
[Solid state Tesla coils]
Mads Barnkob
October 14, 2017, 07:32:17 AM
post Re: SSTC Not Working Correctly
[Solid state Tesla coils]
Laci
October 13, 2017, 04:46:25 PM
post Re: My 160 (?)mm sstc
[Solid state Tesla coils]
oneKone
October 12, 2017, 04:01:42 PM
post Re: SSTC Not Working Correctly
[Solid state Tesla coils]
Uspring
October 12, 2017, 12:26:00 PM
post Re: Counter Poise Grounding for Tesla Coils
[Dual Resonant Solid State Tesla coils]
UweD
October 12, 2017, 12:16:06 PM
post Re: My 160 (?)mm sstc
[Solid state Tesla coils]
Hydron
October 12, 2017, 10:00:33 AM
post Re: Webinar(Oct 24, 2017 15:00CEST): Laminated busbars – how to optimize your design
[Beginners]
T3sl4co1l
October 11, 2017, 10:39:05 PM
post Re: Webinar(Oct 24, 2017 15:00CEST): Laminated busbars – how to optimize your design
[Beginners]
Hydron
October 11, 2017, 11:26:43 AM
post Re: SSTC Not Working Correctly
[Solid state Tesla coils]
Mads Barnkob
October 11, 2017, 10:03:36 AM
post Re: SSTC Not Working Correctly
[Solid state Tesla coils]
Laci
October 10, 2017, 09:37:50 PM
post Re: Webinar(Oct 24, 2017 15:00CEST): Laminated busbars – how to optimize your design
[Beginners]
Mads Barnkob
October 10, 2017, 12:42:05 PM
post Re: Webinar(Oct 24, 2017 15:00CEST): Laminated busbars – how to optimize your design
[Beginners]
Hydron
October 10, 2017, 10:45:45 AM
post Re: Smartphone scientific oriented games: list your best!
[General chatting]
Mads Barnkob
October 09, 2017, 09:40:02 AM
post Re: Counter Poise Grounding for Tesla Coils
[Dual Resonant Solid State Tesla coils]
Mads Barnkob
October 09, 2017, 09:08:36 AM
post Re: AliExpress/ Chinese drsstc drivers
[Dual Resonant Solid State Tesla coils]
Mads Barnkob
October 09, 2017, 09:07:22 AM
post Re: AliExpress/ Chinese drsstc drivers
[Dual Resonant Solid State Tesla coils]
CCX191
October 08, 2017, 06:45:56 AM
post Re: Smartphone scientific oriented games: list your best!
[General chatting]
futurist
October 07, 2017, 01:15:32 PM
post Re: AliExpress/ Chinese drsstc drivers
[Dual Resonant Solid State Tesla coils]
futurist
October 07, 2017, 01:08:48 PM
post AliExpress/ Chinese drsstc drivers
[Dual Resonant Solid State Tesla coils]
oneKone
October 07, 2017, 02:10:18 AM
post Smartphone scientific oriented games: list your best!
[General chatting]
Mads Barnkob
October 06, 2017, 02:59:00 PM
post Re: My 160 (?)mm sstc
[Solid state Tesla coils]
Mads Barnkob
October 06, 2017, 02:49:17 PM
post Re: My 160 (?)mm sstc
[Solid state Tesla coils]
oneKone
October 06, 2017, 01:32:41 PM
post Re: My 160 (?)mm sstc
[Solid state Tesla coils]
Mads Barnkob
October 06, 2017, 08:57:35 AM
post Re: subcooledheatpump YouTube channel
[General chatting]
Mads Barnkob
October 06, 2017, 08:26:14 AM
post Re: Kaizer Power Electronics, website, youtube
[Hobby sites]
Mads Barnkob
October 06, 2017, 08:21:53 AM
post Re: Attempting the Kaizer sstc II
[Solid state Tesla coils]
oneKone
October 06, 2017, 01:54:02 AM
post Re: My 160 (?)mm sstc
[Solid state Tesla coils]
oneKone
October 06, 2017, 01:45:34 AM
post subcooledheatpump YouTube channel
[General chatting]
oneKone
October 05, 2017, 02:15:30 PM
post Re: Kaizer Power Electronics, website, youtube
[Hobby sites]
oneKone
October 05, 2017, 02:11:46 PM
post Webinar(Oct 24, 2017 15:00CEST): Laminated busbars – how to optimize your design
[Beginners]
Mads Barnkob
October 05, 2017, 10:49:22 AM
post Re: My 160 (?)mm sstc
[Solid state Tesla coils]
Mads Barnkob
October 04, 2017, 08:44:41 AM
post Re: My 160 (?)mm sstc
[Solid state Tesla coils]
oneKone
October 04, 2017, 08:03:10 AM
post Re: My 160 (?)mm sstc
[Solid state Tesla coils]
Mads Barnkob
October 03, 2017, 11:15:20 AM
post Re: My 160 (?)mm sstc
[Solid state Tesla coils]
oneKone
October 03, 2017, 12:58:10 AM
post Re: Very high voltage, series connected, electrolytic capacitor bank
[Capacitor banks]
Mads Barnkob
October 01, 2017, 06:21:52 PM
post Re: My 160 (?)mm sstc
[Solid state Tesla coils]
oneKone
October 01, 2017, 05:40:49 AM
post Re: SSTC Not Working Correctly
[Solid state Tesla coils]
Laci
September 30, 2017, 02:02:42 PM