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teravolt

Fri Mar 30 2007, 04:52AM

Registered Member #195 Joined: Fri Feb 17 2006, 08:27PM
Location: Berkeley, ca.
Posts: 1111

I am designing a fiber optic drive DRSSTC from scratch and I have enterd the stage for the primary construction. When I am ready what is the recomendation for tuning poles? I have the book "Building the modern day tesla coil" and Eastern Voltage Research said that in small ciols the primary is tuned low and does not go into larger coils. How do you guys deal with notching and large coils. If you need details of my DRSSTC let me know

Steve Ward

Fri Mar 30 2007, 03:58PM

Registered Member #146 Joined: Sun Feb 12 2006, 04:21AM
Location: Austin Tx
Posts: 1055

Im sure ive explained this before, but with larger coils, i find that allowing a notch is fine (typically occurs in 6-9 cycles). The notch is then your shut off point, which maximizes efficiency overall. Its found that with big coils, you can typically drive enough energy in those 6-9 cycles to achieve good spark lengths, while little coils just cant get enough energy in that short time, so you detune very far to alter the effects of notching (it does ultimately notch, since this is a physical phenomena dealing with energy being transfered to the load).

But, you shouldnt have much to worry about designing. Make your primary have more inductance than you think you need, and then just find what tuning works best for your system since you will need to fine tune it by hand anyway.

And what exactly is meant by fiber optic drive? Just the interrupter or is the RF drive signal also by fiber?

teravolt

Sat Mar 31 2007, 05:20AM

Registered Member #195 Joined: Fri Feb 17 2006, 08:27PM
Location: Berkeley, ca.
Posts: 1111

thanks for the reply, I am using fiber optics to isolate 4 CM600HA-24. Each fiber runs the driver to each IGBT. I can get rise and fall times under a microsecond. Each driver uses an independent power supply (on board regulators). The same thing can be done with optos. I prefer this method to transformers because I feal it gives me more controle over the gate time. with 2 IXDD414PI I can drive the gate with less than an ohm at 28A or more.

ragnar

Sat Mar 31 2007, 05:44AM

Registered Member #63 Joined: Thu Feb 09 2006, 06:18AM
Location:
Posts: 1425

Darnit, where do you and Firkragg find this beautiful double-sided tinned donut-pad-prototype-board?

edit: So-called "Vector" is it? I purchase it as "prototyping clad", but can only find single-sided bare copper, which corrodes so quickly. ^_^

Hazmatt_(The Underdog)

Sat Mar 31 2007, 06:19AM

Registered Member #135 Joined: Sat Feb 11 2006, 12:06AM
Location: Anywhere is fine
Posts: 1735

BP don't you know about Vector? It's out there but the stuff new is $$$

Marko

Sat Mar 31 2007, 11:19AM

Registered Member #89 Joined: Thu Feb 09 2006, 02:40PM
Location: Zadar, Croatia
Posts: 3145

Hi! *jelaous of those beautiful bricks and drivers*

Darnit, where do you and Firkragg find this beautiful double-sided tinned donut-pad-prototype-board?

All my tinned boards are tinned on my own, they were copper before.
Anyway, due to lead contet solder oxidizes after some time and still hardens the soldering... I never tried a RoHS solder yet.

Using lotlack spray would actually make soldering more easy than tinning.

I did although have some silvered and gold-plated double sided proto boards here. They are superior for soldering under any conditions! I don't have much of them left unfortunately.

Im sure ive explained this before, but with larger coils, i find that allowing a notch is fine (typically occurs in 6-9 cycles). The notch is then your shut off point, which maximizes efficiency overall. Its found that with big coils, you can typically drive enough energy in those 6-9 cycles to achieve good spark lengths, while little coils just cant get enough energy in that short time, so you detune very far to alter the effects of notching (it does ultimately notch, since this is a physical phenomena dealing with energy being transfered to the load).

I also noticed that my coil notches after just few cycles whan I tuned it for *best looking spark*. I would have to run 2 notches if I wanted 200 or so us of on time.
I still need proper capacitors, calibrated CTs snd some time...

Tom540

Sat Mar 31 2007, 04:52PM

Banned on 3/17/2009.
Registered Member #487 Joined: Sun Jul 09 2006, 01:22AM
Location:
Posts: 617

Frys sells boards like that. If there isn't one near you you can try the website

I don't know if they ship overseas though.

teravolt

Sat Mar 31 2007, 05:26PM

Registered Member #195 Joined: Fri Feb 17 2006, 08:27PM
Location: Berkeley, ca.
Posts: 1111

vector is to expensive so I use use Twin Industries [http://twinind.com/catalog.php?id=7] to do my prototype PCB's

. The driver PCB is done with ExpressPCB and there free softwere package. At some point I am going to make a surface mount version of the controler. I Got 100 of the 942C caps at Richardson Electronics in two weeks

Marko

Sat Mar 31 2007, 07:13PM

Registered Member #89 Joined: Thu Feb 09 2006, 02:40PM
Location: Zadar, Croatia
Posts: 3145

Wow teravolt, absolutely beautiful design... There is a real demand for 942C caps in last times, guys at rell must be wondering about that...

Just spotted it, what are those busbars made off?

teravolt

Sat Mar 31 2007, 10:01PM

Registered Member #195 Joined: Fri Feb 17 2006, 08:27PM
Location: Berkeley, ca.
Posts: 1111

1/8"aluminuim plate 5.39uf esr less than 1m ohm

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