John and PhillipThis is interesting as I have done loose testing on + - 1 volt variance on my dual 833A coil tube filaments. I have always used a variac with a volt meter to ramp up the tubes and let them normalize. I have two 5 volt rather large HV rectifier filament transformers in series and the center tap grounded (no staccato). They are very stable. I tested between 9 and 11 volts ( I don't have a spreadsheet ) I used a Wavetech meter to measure the filament AC voltage.
I found that as I approached 11 filament volts the plates would get red faster and the coil would start to loose streamer length. As I approached 9 volts the coil would really start to loose streamer length, but the tubes didn't seem to care.
This is hardly a proper scientific method, but as long as I was using the variac I just did a quick check. Of course, this all is hardly surprising as we are pushing these tubes and 10 volts is the designed proper voltage. So I always run the tubes at 10 volts.
There are so many parameters involved that it is hard to conclude much except run the filaments were they were designed to run. The tubes are used RCA units that I got from a ham rig. I have been using the same pair for three years.
John W. G. John W. Gudenas, Ph.D. Professor of Computer Science On Oct 23, 2008, at 6:43 PM, futuret@xxxxxxx wrote:
It would be interesting to put the existing filament transformer on a variac, and raise up the input voltage some, so that the output equals the voltage using your homemade transformer to verify that 10.4 volts causes bad running of the coil, with either transformer. This would just be a test. You might wonder why I'd even suggest something like this, but when I work on coils, I constantly verifying things of that sort to be sure I'm not mistaken about anything. John -----Original Message----- From: Phillip Slawinski <pslawinski@xxxxxxxxx> To: Tesla Coil Mailing List <tesla@xxxxxxxxxx> Sent: Thu, 23 Oct 2008 6:48 pm Subject: Re: [TCML] Odd VTTC Streamer Behaviorusually a higher filament voltage such as 10.3 or 10.5 works well, and doesn't cause problems except for shortened tube life.Well, maybe in most cases, but not this case. I tried moving the grid way up, and way down and still could not get the coil to behave. When I took the voltage down the coil was working better than with the old transformer.Regarding those 90 degree small streamers. My 20" sword spark coil had them too after I pushed the spark to 20" from the initial 18" orso.John_______________________________________________ Tesla mailing list Tesla@xxxxxxxxxxxxxx http://www.pupman.com/mailman/listinfo/tesla _______________________________________________ Tesla mailing list Tesla@xxxxxxxxxxxxxx http://www.pupman.com/mailman/listinfo/tesla
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