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 - dexter

Pages: [1] 2
1
1. A DRSSTC driver always works at the resonance of the primary LC. The intrerupter doesn't change it.
A problem with the onetesla driver is the lack of overcurrent protection. They get around it by having the coil tuned and by controlling the on time with their intrerupter.
If you use their driver for other coils you risk exceeding the current capabilities of the IGBT's and blow them off.
2. Yes you need to adjust the number of primary turns for a different secondary coil. JAVATC is a great tool but tuning still has to be done manually. Given the lack of overcurrent protection of the onetesla driver you risk blowing the IGBT's when tuning the coil.
3. The bottom of the secondary coil must be connected to earth. For small coils the earth pin of the outlet can be used but for bigger and powerful coils a separate earth ground must be used. Or a sheet of metal could be used but it has to be some distance away from the primary coil and i think it should be at least connected to mains earth.  As for the driver it should be shielded (placed inside a metal box) and connected to mains earth.
4. 5. The polarity of primary coil and feedback transformer have to be in phase. If your coil doesn't starts flip the feedback transformer or the primary coil polarity

2
Capacitor banks / Re: Bought huge capacitors
« on: June 16, 2019, 08:25:16 PM »
in a 2015 post from 4hv by Kizmo about triggered spark gaps he says it works at any capacitor voltage even as low as 20V
https://4hv.org/e107_plugins/forum/forum_viewtopic.php?p=1&id=171055#post-171722

also saw some russians playing with a homemade taser on the mains wiring of their house which had the same effect as a triggered spark gap

3
I've seen a paper about calculating the self capacitance of a solenoid and in one of the methods they used the self resonance frequency, measured inductance and the length of wire to calculate the self capacitance.
but in their calculation they used l=λ/2 (l= length of wire)

i'm confused... which formula λ/2 or λ/4 describe the self resonance of a solenoid?

4
Its a nice idea, but 50 Hz is not giving the right sound is it? Since its not going positive and negative, but just on/off, maybe 100 Hz is a better emulation of full wave rectified, non-smoothed mains sound.

i used 100Hz because 50 didn't sound right

5
Capacitive and inductive reactances depends on capacitance/inductance and frequency.
Xc=-1/(2pi X f X C)
Xl=2pi X f X L

"Resonance occurs when capacitive and inductive reactances are equal to each other."
that means: Xl=Xc
rearrange the terms and you get: Frez = 1/(2pi X sqrt(L X C))

So whenever you change the capacitance or the inductance the frequency at which Xc and Xl becomes equal (also known as resonant frequency) also changes.

Mads-
   I studied resonant circuits back in the early 1950's.  I vaguely remember that there is some negative "cost" to having L and C too far away from eachother, but I don't know why.
the energy stored in inductor and capacitor is:
Wc=0.5 x C x V^2
Wl=0.5 x L x I^2
At resonance Wc=Wl
For an inductance heater you need high current in the work coil. To achieve this a small inductance coil is used but
 a large capacitor with a high voltage rating is required. So the "negative cost" translate to a monetary cost :)

6
I too didn't understood exactly how UD2.9 works so i made it on a bread board (just the 74HC74 74HC08 74HC14 chips and the passives) feed it signals for FB OCD Interrupter and it works as advertised.
J16 open - works like UD2.7
J16 closed - no output for the duration of the OCD


yellow trace - intrerupter
green trace - output of one of the 74HC08 gates before the UCC

How the driver generate the dead time?
It doesn't. The signal that goes to the GDT comes from the Q and Q- of the comparator which are 50% duty cycle signals and no disproportionate delays seem to be added on the UCC and on the power stage

7
Dual Resonant Solid State Tesla coils / Re: My first DRSSTC on bricks
« on: April 30, 2019, 12:32:24 AM »
What about the number of series and parallel capacitors?The datasheet doesn't mention the current rating,but in theory the more capacitors in parallel,the less the ESR is or in these applications it makes not much sense?For example at 110kHz,800A which one should I choose, 0.2uF 6kV(more in parallel) or 0.15 8kV(more in series)? (in theory more in parallel)

You can calculate Ipk=C*dV/dT

If 6kV is enough for your coil i'd go for 0.2uF (more capacitance and more caps in parallel)

8
Beginners / Re: SSTC wıth a balast
« on: April 27, 2019, 09:09:31 PM »
connecting the primary coil the other way around even if both coils are turned in the same direction is still the first thing to try on a secondary feedback based SSTC when you get no sparks

9
Beginners / Re: SSTC wıth a balast
« on: April 27, 2019, 08:56:36 PM »
But there are no sparks forming on the tesla coil. What could the problem be?

try connecting the primary coil the other way around

10
Spark gap Tesla coils / Re: Question about secondary
« on: April 18, 2019, 09:20:15 PM »
on all my SSTC's i used carbohydrate foam (also known as wood) for the end caps and never had an issue

11
Use a monostable with the time constant a bit higher than the length of the noise or a low pass RC between 2 Schmitt trigger gates with the time constant a bit higher than the length of the noise

12
This thread motivated me to finally make a HV transformer.
The core is the largest TV flyback core i had.
The coil form is made from 2mm thick acrylic glued on a 18mm PVC pipe.
Wound about 2000 turns of 0.25mm wire on six 2.5mm slots by 9.5mm thick and 16 turns primary with multiple taps.
Vacuumed it under oil for a few hours using 2 fridge motors.
Connected it to a full bridge of skm200gb123d bricks running at 30kHz and 130V



/>Here is running interrupted to give it mains humm

13
Solid state Tesla coils / Re: GDT Experiments
« on: March 28, 2019, 12:37:42 AM »

I am using UCC37322 instead of TC4420, so that might be the reason.
I also wondered what causes the dead time ( well to be honest I would not know what does it even if there was a dedicated component )
What controls the dead time was going to be my next question.


UCC37322 is faster than TC4420...
Given that you got the same deadtime in both cases at different frequencies i'd say the propagation delay from an extra schmitt inverter on one of the UCC's is what produces the deadtime.
What is the part number of U6 (from schematic) that you are using?

14
Solid state Tesla coils / Re: GDT Experiments
« on: March 27, 2019, 10:52:46 PM »
That waveform confused me a bit until I realized that there is "deadtime" in the signal. Only recently I watched a video on YouTube on that topic - quite glad I recognized it in the waveform.  ;D

You have about 1.8us of deadtime in both shoots and i can't figure it out how...
The Half Bridge SSTC schematic doesn't have any built in deadtime and the TC4420 have delay times less than 100ns and matched Rise and Fall times of 25ns or are you using different IC's?

15
Dual Resonant Solid State Tesla coils / Re: UD 2.7C Build
« on: March 03, 2019, 09:33:29 PM »
So I must connect a couple of GDT’s to it then ?

the UCC32xxx in a UD2.7 drives some mosfets so i don't see a problem with powering it up without a GDT connected

16
Dual Resonant Solid State Tesla coils / Re: UD 2.7C Build
« on: February 27, 2019, 06:23:40 PM »
here's a home made version of UD2.x
doesn't look that great but it does the job and it was a fun learning experience

17
How much Amps can you push with the new  SKM200GB123 bridge?

18
@Dexter,
Seems like GDT is working fine, waveform on Fet gates is correct, so I think i got the GDT right this time.

The waveform on Fet's gates will be correct regardless if the phasing is not
Depending on how you connected the primary and secondary sides of the GDT (especially when the leads ate twisted) and the way you connected primary coil to the bridge you can end up in a situation where the signal picked up by the antenna is in anti-phase with what you have on primary coil.
When this happen you get just a small glow at the breakout point. This is easily countered by reversing the connections A and B

19

What would be next step before I connect it to my Variac ?


in nearly all my antenna feedback SSTC's i had to reverse the polarity of the primary side of the GDT so that the primary coil is in phase with the secondary coil
If the phasing is wrong the output of the coil will be very small to the point i had to draw an arc in order to see it but as soon i fixed the phasing i got few cm streamers even with around 30V on the bridge.

20
Dual Resonant Solid State Tesla coils / Re: (DR)SSTC II
« on: December 26, 2018, 01:54:10 AM »
Can I measure the primary current with my oscilloscope on the OCD CTs?Will the probe put unwanted noise into the driver?

better wind another CT for measurements (can have different specs) this way you know there won't be any external noise

my coil didn't matched javaTC specs so i had to tune it through trial and error...

Pages: [1] 2

* Recent Topics and Posts

post Re: Next Gen DRSSTC
[Dual Resonant Solid State Tesla coils]
Mads Barnkob
Today at 02:51:26 PM
post Re: What is the true in tuning guide?
[Dual Resonant Solid State Tesla coils]
Mads Barnkob
Today at 02:48:02 PM
post Re: A problem solved with hand tools
[General chatting]
Mads Barnkob
Today at 01:48:08 PM
post Re: Kaizer half bridge driver
[Dual Resonant Solid State Tesla coils]
Mads Barnkob
Today at 01:45:00 PM
post Re: A problem solved with hand tools
[General chatting]
Hydron
Today at 11:21:29 AM
post What is the true in tuning guide?
[Dual Resonant Solid State Tesla coils]
VNTC
Today at 10:01:21 AM
post A problem solved with hand tools
[General chatting]
klugesmith
Today at 07:52:41 AM
post Re: Welcome new members, come say hello and tell a little about yourself :)
[General chatting]
klugesmith
Today at 07:33:30 AM
post Re: tesla coil varnish is dumb
[Solid state Tesla coils]
Hydron
July 14, 2019, 10:49:03 PM
post Re: tesla coil varnish is dumb
[Solid state Tesla coils]
T3sl4co1l
July 14, 2019, 09:59:40 PM
post Re: tesla coil varnish is dumb
[Solid state Tesla coils]
Mads Barnkob
July 14, 2019, 08:20:52 PM
post Re: Next Gen DRSSTC
[Dual Resonant Solid State Tesla coils]
Netzpfuscher
July 14, 2019, 06:06:30 PM
post tesla coil varnish is dumb
[Solid state Tesla coils]
Fumeaux
July 14, 2019, 05:29:10 PM
post Led Closeups with Mobile phone and lens .
[Smart phones]
DashApple
July 14, 2019, 03:00:09 PM
post Re: Drsstc 3
[Dual Resonant Solid State Tesla coils]
Mads Barnkob
July 14, 2019, 02:06:26 PM
post Re: DRSSTC in brust mode
[Dual Resonant Solid State Tesla coils]
Mads Barnkob
July 14, 2019, 02:04:22 PM
post Re: Twin System Build
[Dual Resonant Solid State Tesla coils]
oneKone
July 14, 2019, 01:27:18 AM
post Re: DRSSTC in brust mode
[Dual Resonant Solid State Tesla coils]
johnf
July 14, 2019, 01:22:15 AM
post Re: Drsstc 3
[Dual Resonant Solid State Tesla coils]
oneKone
July 13, 2019, 03:48:54 PM
post DRSSTC in brust mode
[Dual Resonant Solid State Tesla coils]
SAMGO
July 13, 2019, 04:17:55 AM
post Re: Kaizer half bridge driver
[Dual Resonant Solid State Tesla coils]
donnersm
July 12, 2019, 08:54:54 PM
post Re: Kaizer half bridge driver
[Dual Resonant Solid State Tesla coils]
profdc9
July 12, 2019, 07:16:40 PM
post Re: Kaizer half bridge driver
[Dual Resonant Solid State Tesla coils]
profdc9
July 12, 2019, 06:33:00 PM
post Smooth corona or heavy spark, RF wave radiation frequency of Tesla coil drops ve
[Dual Resonant Solid State Tesla coils]
VNTC
July 12, 2019, 11:09:28 AM
post Re: Drsstc 3
[Dual Resonant Solid State Tesla coils]
Mads Barnkob
July 12, 2019, 09:56:38 AM
post Re: Drsstc 3
[Dual Resonant Solid State Tesla coils]
oneKone
July 12, 2019, 01:23:58 AM
post Re: Completed my pulsed power generator
[Capacitor banks]
MRMILSTAR
July 11, 2019, 05:48:27 PM
post Re: Completed my pulsed power generator
[Capacitor banks]
Mads Barnkob
July 11, 2019, 02:58:13 PM
post Re: Kaizer half bridge driver
[Dual Resonant Solid State Tesla coils]
Mads Barnkob
July 11, 2019, 02:45:24 PM
post Kaizer half bridge driver
[Dual Resonant Solid State Tesla coils]
donnersm
July 11, 2019, 06:59:01 AM
post Completed my pulsed power generator
[Capacitor banks]
MRMILSTAR
July 11, 2019, 05:43:31 AM
post Re: Twin System Build
[Dual Resonant Solid State Tesla coils]
fnordest
July 11, 2019, 01:05:42 AM
post Re: "LightningStorm" VTTC project
[Vacuum tube Tesla coils]
Avenger
July 09, 2019, 07:31:37 PM
post Re: Siemens Polyphos 30 xray machine
[X-ray]
oneKone
July 09, 2019, 04:48:29 PM
post Re: Siemens Polyphos 30 xray machine
[X-ray]
Mads Barnkob
July 09, 2019, 03:53:37 PM
post Re: Help for people buying the "12-48 Volt 1800/2500 Watt ZVS induction Heater"
[Electronic circuits]
Bert911
July 09, 2019, 08:45:17 AM
post DRSSTC schematic for simulating (primary feedback self-oscillating)
[Dual Resonant Solid State Tesla coils]
VNTC
July 09, 2019, 06:10:12 AM
post Re: Help for people buying the "12-48 Volt 1800/2500 Watt ZVS induction Heater"
[Electronic circuits]
petespaco
July 08, 2019, 09:13:42 PM
post Re: Driving the LED lights with the streamers
[Dual Resonant Solid State Tesla coils]
johnf
July 08, 2019, 09:02:20 PM
post Re: Drsstc 3
[Dual Resonant Solid State Tesla coils]
oneKone
July 08, 2019, 03:57:17 PM
post Re: Driving the LED lights with the streamers
[Dual Resonant Solid State Tesla coils]
Fumeaux
July 08, 2019, 12:05:54 PM
post Driving the LED lights with the streamers
[Dual Resonant Solid State Tesla coils]
donnersm
July 08, 2019, 11:04:00 AM
post Re: Aliexpress cheap CM300-24H
[Dual Resonant Solid State Tesla coils]
SAMGO
July 08, 2019, 10:43:33 AM
post Re: Hydron's 160mm DRSSTC and topload current measurements
[Dual Resonant Solid State Tesla coils]
Uspring
July 08, 2019, 09:59:49 AM
post Re: Aliexpress cheap CM300-24H
[Dual Resonant Solid State Tesla coils]
oneKone
July 08, 2019, 08:04:44 AM
post Re: Help for people buying the "12-48 Volt 1800/2500 Watt ZVS induction Heater"
[Electronic circuits]
Mads Barnkob
July 07, 2019, 08:19:33 PM
post Re: Twin System Build
[Dual Resonant Solid State Tesla coils]
Mads Barnkob
July 07, 2019, 08:03:59 PM
post Re: Help for people buying the "12-48 Volt 1800/2500 Watt ZVS induction Heater"
[Electronic circuits]
petespaco
July 07, 2019, 05:28:04 PM
post Re: Help for people buying the "12-48 Volt 1800/2500 Watt ZVS induction Heater"
[Electronic circuits]
petespaco
July 07, 2019, 05:24:20 AM
post Re: Induction Heater schematic modification
[Electronic circuits]
johnf
July 07, 2019, 04:53:29 AM