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Author Topic: Tesla primary coil rectification  (Read 12626 times)

Jeg

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Tesla primary coil rectification
« on: November 21, 2013, 11:45:43 AM »
Hi to all :)

After the spark gap in a tesla coil arrangement, i take some bursts at the BPS frequency. Those bursts consists of the oscillation frequency between discharge cap and primary coil which is around 300KHz. In a try to "play" with this signal, i am thinking of rectifying it. The voltage is around 4KV but current is unknown.

My question refers to which kind of diodes may i use so to rectify it without problems. I look for something cheap and capable of handling all these peak currents.

Tnks
Jeg

gyulasun

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Re: Tesla primary coil rectification
« Reply #1 on: November 21, 2013, 02:33:29 PM »
Hi to all :)

After the spark gap in a tesla coil arrangement, i take some bursts at the BPS frequency. Those bursts consists of the oscillation frequency between discharge cap and primary coil which is around 300KHz. In a try to "play" with this signal, i am thinking of rectifying it. The voltage is around 4KV but current is unknown.

My question refers to which kind of diodes may i use so to rectify it without problems. I look for something cheap and capable of handling all these peak currents.

Tnks
Jeg

Hi Jeg,

You should know the possible peak or normal currents levels involved (considering worst case) and choose diodes accordingly. Price strongly depends on HV reverse breakdown and forward current spec, together with fast speed, see this for instance:
http://www.ebay.com/itm/2CLG-10KV-1A-High-Voltage-Diode-HV-Rectifier-Tesla-Ham-/271096259991 

Some more choices for 10kV diodes (unfortunately up to max 1 A current): http://www.ebay.com/bhp/10kv-diode 

Of course you can search for 5 or 6 kV diodes too.

Jeg

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Re: Tesla primary coil rectification
« Reply #2 on: November 21, 2013, 02:56:50 PM »
Hey Gyula :)
I am looking for high current ones and i'll fix the desired voltage by making strings. I just don;t know if frequencies around 300-500KHz need special diodes. Will silicon ones make a decent rectification without speed problems? Or i have to look for germanium or others special types!

gyulasun

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Re: Tesla primary coil rectification
« Reply #3 on: November 21, 2013, 04:24:44 PM »
...
 I just don;t know if frequencies around 300-500KHz need special diodes. Will silicon ones make a decent rectification without speed problems?

Yes, look for fast and / or super fast diodes, these have less than 80-100 nanosecond reverse recovery time so would not heat just due to the higher frequency involved like an 1N4007 50-60 Hz type. here are some:
http://www.ebay.com/itm/RHRG75120-High-Current-High-Voltage-Fast-Soft-Recovery-Diode-75A-1200V-Qty-2-/171177259669?pt=LH_DefaultDomain_0&hash=item27daf5b295

http://www.ebay.com/itm/RHRG30120-Ultra-Fast-Soft-Recovery-Power-Rectifier-1200V-30A-65ns-Qty-2-/181262817795?pt=LH_DefaultDomain_0&hash=item2a341b1a03

TinselKoala

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Re: Tesla primary coil rectification
« Reply #4 on: November 21, 2013, 09:45:25 PM »
Sounds like a good way to let the magic smoke out of some expensive diodes!

Why in the world would you want to kill that nice 300kHz tank oscillation by rectifying it? The place to rectify a primary Tesla coil circuit is _before_ the sparkgap and tank circuit. Once you have a nice ringing in the tank, you will be wasting half the energy with a half-wave (single) rectifier, and you will kill the oscillation completely with a fullwave bridge.

I'm not saying you shouldn't try it (if you can afford the diode stack you will need to withstand your primary voltage peaks) but I am curious as to the motivation and the expected result.

the_big_m_in_ok

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Re: Tesla primary coil rectification
« Reply #5 on: November 22, 2013, 01:53:42 AM »
Hi to all :)

After the spark gap in a tesla coil arrangement, i take some bursts at the BPS frequency. Those bursts consists of the oscillation frequency between discharge cap and primary coil which is around 300KHz. In a try to "play" with this signal, i am thinking of rectifying it. The voltage is around 4KV but current is unknown.

My question refers to which kind of diodes may i use so to rectify it without problems. I look for something cheap and capable of handling all these peak currents.

Tnks

Jeg
       Time's short on this computer.   But, my question is...
Do you have a schematic of your own, or else, an Internet schematic of this circuit you can upload?
Otherwise, a couple of strings of diodes in opposite directions to a smoothing capacitor in parallel and then to a battery bank is the way I would go about it.

--Lee

d3x0r

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Re: Tesla primary coil rectification
« Reply #6 on: November 22, 2013, 03:32:43 AM »
I saw two ways to capture that recently... getting the full potential without extremely complex diodes. ( they recommend silicon tubing around said diodes filled with oil)


Add another spark gap from the end of the high voltage to a cap.  This will take off the very top of the voltage, and allow the resonance to rebuild in the circuit.


http://www.youtube.com/watch?v=px14OF1D3EA


The other way, which does't get as much is an avermenko plug , or even a single diode to another coil using that coil as a pickup; the diode isolates it from the coil a bit ..


http://www.youtube.com/watch?v=Jwk_2Zp_P4Q
http://www.youtube.com/watch?v=JWD0Wy_UOEA




the_big_m_in_ok

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Re: Tesla primary coil rectification
« Reply #7 on: November 23, 2013, 04:39:53 AM »
I saw two ways to capture that recently... getting the full potential without extremely complex diodes. ( they recommend silicon tubing around said diodes filled with oil)


Add another spark gap from the end of the high voltage to a cap.  This will take off the very top of the voltage, and allow the resonance to rebuild in the circuit.


http://www.youtube.com/watch?v=px14OF1D3EA


The other way, which does't get as much is an avermenko plug , or even a single diode to another coil using that coil as a pickup; the diode isolates it from the coil a bit ..


http://www.youtube.com/watch?v=Jwk_2Zp_P4Q
http://www.youtube.com/watch?v=JWD0Wy_UOEA
       @d3x0r
Your response got me thinking:   There was a patent application I finally saw reference to on GOOGLE  IMAGES...
 
This is a dresription of the source of my info:
      A Practical Guide to Free-Energy Devices,   Chapt. 11
(scroll down the page until you get to the reference to...
       Paulo and Alexandra Correa and their Patent Application,   2006/0,082,334
 
(It does show a double set ofreversed polarity diodes attached to, and leaving, a Tesla coil torus.    The output can be capacitor-filtered and tied to a bank of batteries, of course.)
 
Note:
This computer is borrowed and the software is very 'third-party-originated' to where the Internet function is barely useful.   It is free for me to use as long as my butt and thighs can stand sitting here in this chair, so I guess I shouldn't complain too much, I suppose.
       I can only give you the description above to go by and you can GOOGLize it if you like.
 
Good thinking, though, d3x0r.   This might be something to think about later when I have more time.
 
--Lee

Jeg

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Re: Tesla primary coil rectification
« Reply #8 on: November 24, 2013, 01:19:23 PM »
Thanks for the answers guys :)

I didn;t have the time to watch the videos but i'll do it tonight and i'll come back on this.

My main purpose is to rectify the main signal-oscillation of lets say about 400KHz, so to be able to extract the BPS frequency and use it for power supply. I am thinking to handle this the same way as a simple AM receiver.


Selekolela

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Re: Tesla primary coil rectification
« Reply #9 on: November 25, 2013, 02:07:01 PM »
I am not going to comment on the topic per say but I would just like to get this out there as I have had some real success with this setup looks like the two coils on the top are somehow being influenced by the dialectric field of the topload on the first secondary.
This setup really increases the magnification and makes the hair stand up on anyone in the vicinity.
Hope this helps someone out there.

Jeg

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Re: Tesla primary coil rectification
« Reply #10 on: November 27, 2013, 01:24:46 PM »
@ d3x0r
Interesting videos, i just don't see how to use it in my project. The idea is to rectify the carrier around 300KHz, and then to use the bps frequency as power supply to charge a new capacitor, or just to watch with a dc voltmeter any changes according to the circuit modifications.

@ Selecolela

Nice idea. 3 secondaries, one in the other. The voltage multiplication should be very high! By the way whats your primary's inductance and resistance?  (Just to compare it with mine which is 127μΗ)

I found this diode and i already ordered some pieces. I will use 10 diodes in series for doing the job. Total cost 44 Euros. Any other and cheaper idea?

Well, i intend to connect my house's ground rail to the negative leg of the discharge cap. Is it ok?
The equipment is a MOT which outputs 2200V AC, a full wave rectifier, a smoothing capacitor, a charging coil and finally the discharge cap. I think that i already tested in the past and something didn't go well but i am not sure and i would like to test it again.

Tnks
Jeg