833A

To: "'Tesla List'" <tesla-at-pupman-dot-com>
Subject: 833A
From: Tesla List <tesla-at-stic-dot-net>
Date: Fri, 27 Feb 1998 22:49:31 -0600
Approved: tesla-at-stic-dot-net

----------
From:  D.C. Cox [SMTP:DR.RESONANCE-at-next-wave-dot-net]
Sent:  Thursday, February 26, 1998 8:01 PM
To:  Tesla List
Subject:  Re: 833A

to: Greg H:

The 833C (commercial) is a much more rugged tube for Tesla coil use.  It
can be pushed harder and runs cooler overall in class C service.  Since you
got the 833A for free -- stick with it -- it still works just fine for a
nice coil with a 24 inch long spark running 3 kV on the plate at 1200 ma. 
Be sure to use plenty of plastic shielding though as 3 kV at this current
will cook you -- like really fast -- if you bump it.

DR.RESONANCE-at-next-wave-dot-net



> From:  vonpostel [SMTP:vonpostel-at-prodigy-dot-net]
> Sent:  Wednesday, February 25, 1998 4:50 AM
> To:  Tesla List
> Subject:  Re: 833A
> 
> Tesla List wrote:
> > 
> > ----------
> > From:  Gregory R. Hunter [SMTP:ghunter-at-mail.enterprise-dot-net]
> > Sent:  Tuesday, February 24, 1998 12:14 PM
> > To:  Tesla List
> > Subject:  833A
> > 
> > Hi Guys,
> > 
> > I lucked up on an 833A triode (for free!).  I have no experience
> > with the big tube.  Is it OK to mount it horizontally?  I plan to
> > run mine pretty hot using a 1KVA MOT for +B. 
> 
> > yielded a nice, open-frame 5" blower--suitable for cooling the tube?
> > Any advice on care & feeding of the 833A would be much appreciated.
> > 
> > Greg
> > 
> > East Anglia, UK
> Greg:
> 	 General Electric Transmitting Tube manual, in talking about forced-air
> cooling, says: "....an air flow of 40 cfm froma two-inch diameter nozzle
> directed verticaly downward on bulb between grid and plate seals is
> required." (When running in maximum ICAS condition.   "Operating
> position....vertical, filament terminals up or down horizontal with
> plate in a plane vertical."  
> 
> Typical ICAS operating conditions, class C oscillator, with forced air
> cooling:
> 
> Filament: 10 volts 10 amps
> D.C. plate voltage: 4000
> D.C. grid voltage: - 225 volts obtained frm a fixed supply or 2400
> ohm 	   grid resistor or 380 ohm cathode resistor
> D.C. plate current: 500 MA
> D.C. grid current (approx.) : 95 MA  This will vary with the load
> impedance. 
> Peak r.f. grid input voltage (approx.): 415 v. peak
> Driving power: 35 watts.
> Plate power output: 1600 watts.
> 
> The connections to the plate and grid should be made with finned heat
> radiating connectors if you intend to push the tube. They don't like to
> have hot seals.  Be generous with the amount of metal in the filament
> connectors.  ( I assume that a socket and connectors didn't come with
> the tube.)  Watch the color of the plate.   My experience has been that
> 833-As don't  give good service if you try to  run them  more than a
> very dark cherry red. By good service I mean 7 days a week, 24 hrs per
> day. The typical operation above is for intermittant commercial amateur
> service.  
> 
> Hope this helps.
> 
> Ray
>