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Steve Conner

Sat Apr 25 2009, 08:10AM

Registered Member #30 Joined: Fri Feb 03 2006, 10:52AM
Location: Glasgow, Scotland
Posts: 6706

Lol @ new hammer time

Uzzors, maybe you're applying too much anode current? The volt drop of a mercury rectifier is about 10V. What's the resistance of your lamp?

I have a couple of mercury rectifiers, and they just show a cloud of plasma that comes out of the cathode spout and hits the plate. I've never seen it go round the back of the plate.

Myke

Sat Apr 25 2009, 08:33AM

Registered Member #540 Joined: Mon Feb 19 2007, 07:49PM
Location: MIT
Posts: 969

The cloud is very dim compared to the actual space between the filiment and the plate. I dicided, since I am not sure that there is no UV emmitied, that I will stop messing around with it and wait till I get some UV protection for under 400nm (375nm and below would be fine too). Does anyone know of some material that blocks around 356nm and 238nm?

Proud Mary

Sun Apr 26 2009, 10:59PM

Registered Member #543 Joined: Tue Feb 20 2007, 04:26PM
Location: UK
Posts: 4992

I've just bought this splendid pair of diode rectifiers from Lithuania for just Â£14.25 (NOK 137, US$ 21). Postage was only Â£2 - (about $3) and no import taxes to pay now that Lithuania is part of the EU.

Va 55kV RMS
Ia 150mA.

They are 180mm tall.

Are these 'cool pix' as the thread has it? Beauty is in the eye of the beholder, I suppose, and they look lovely to me!

The two of them together will make quite a voltage doubler!

TheBoozer

Mon Apr 27 2009, 12:34AM

Registered Member #1535 Joined: Wed Jun 11 2008, 11:37PM
Location: Northeastern Pennsylvania - USA
Posts: 117

I'm in the process of building a DRSSTC based on Steve Ward's controller. I don't have the IGBT's yet, but I do have a bunch of bricks laying around. To see how well this board performs, I slapped together a full bridge using a pair of cm100dy12h's. This assembly looks neat to me, scary to my family, and maybe interesting to the forum members, so here it is. :)

I live in 60hz land. The DC bus is 170vdc. The coil is a measured 5.6uH, the tank cap is 2.5uF @ 5600vdc or 2100vac. The electrolytics total 7820uF and, wow, get dragged down to 138vdc while the system is running at 12.5arms. Scope shows that it runs at around 42khz.

The DRSSTC controller is set to max pulse width. That's around 250uS. I use the BPS potentiometer to control the current pulled from the wall. The OCD is set to about 420a. It really kicks in when the pipe is removed. :) The highest recorded temperature was 958 degrees farenheight. My thermometer won't go higher than that, but the pipe was glowing a bit. :)

Current through the coil peaks at 400a. After a few minutes of runtime is settles down to 350a. I can't figure out why. I tried two different tank cap assemblies, I keep the IGBT heatsink below 110 degrees. I guess I'll just have to keep beefing up the DC connections?

Not bad for a pair of cm100dy12h's is it? Or is this a poor way of load testing the IGBT's? I guess I'll hafta wait and see what happens in an actual Tesla coil configuration.....

Rich

Cesiumsponge

Mon Apr 27 2009, 02:50AM

Registered Member #397 Joined: Wed Apr 19 2006, 12:56AM
Location: Western Washington
Posts: 125

Some rare Westinghouse 5V filament transformers in bakelite. Two out of three survived shipping

but luckily I only need one.

Not shown are another two nearly identical transformers at 10V output. Both survived shipping. I will be using these in an upcoming project involving a pair of JAN810 tubes and a 872A mercury vapor rectifier.

rectifier

1240800432 397 FT6000 3471307651 E3def4d642 B

Proud Mary

Mon Apr 27 2009, 02:57AM

Registered Member #543 Joined: Tue Feb 20 2007, 04:26PM
Location: UK
Posts: 4992

Cesiumsponge wrote ...

Some rare Westinghouse 5V filament transformers in bakelite. Two out of three survived shipping

I just recently brought a pair of 816 mercury vapour rectifiers (PIV 7.5 kV/ Ia 500mA) and a pair of mercury-argon thyratrons to experiment with, so I'll be very interested to see how your set up works out.

Cesiumsponge

Mon Apr 27 2009, 03:47PM

Registered Member #397 Joined: Wed Apr 19 2006, 12:56AM
Location: Western Washington
Posts: 125

If anyone happens to want to use these, Fair Radio Sales has a quantity of the 5V 7.5A transformers available for $24 each. It uses the 4-pin jumbo bayonet socket, same as the 810, 211, 872A, 838, 845, etc. I can't think of a tube with this socket size and a 5V filament transformer other than the 872A rectifier though.

Hon1nbo

Mon Apr 27 2009, 10:57PM

Registered Member #902 Joined: Sun Jul 15 2007, 08:17PM
Location: Pacific Northwest USA
Posts: 1042

here are some photos of my work-in-progress Capacitor Bank... still choosing a charging circuit, but whatever it is it will have to fit in the Pelican case as well... and here is a link to some Lightning filmed on my high-speed camera: Youtube
for the lightning I used 210 Frames per Second, but will bump it up to 420, or 1000 FPS next time.

teslacoolguy

Tue Apr 28 2009, 01:52AM

Registered Member #1107 Joined: Thu Nov 08 2007, 10:09PM
Location:
Posts: 792

Not sure i would want to take that suitcase through airport security.

Nice setup, what is the energy rating?

...

Tue Apr 28 2009, 02:10AM

Registered Member #56 Joined: Thu Feb 09 2006, 05:02AM
Location: Southern Califorina, USA
Posts: 2445

What are you planning to use that for? And how is the triggered spark gap working out for you?

Also, if it were me I would put the capacitors in dangerous end down, so that you don't have to worry about exposed hv where hands can reach (although a piece of plexiglass over that half of the case would work as well).

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