[TCML] Fwd: Vttc video and math

[Simon <elmontare@xxxxxxxxx>]

Anyone with vttc experience should feel free to email me off list too if youd like. Im sure someone out there on the list besides me enjoys problem solving and just shooting the sh*t about coils :) :)

Somethings im still only partial on - 

I assume no news is good news about my connections at least. 

When i enter the information for my MOT (2000v and 500mA and 60Hz) JavaTC returns 4000Ohms impedance. Am i correct to use this as a value for T1 when trying to match it to the load impedance of the tubes?  In this case 1562Ohms. This sounds ok to me. Are there tubes out there that will really exceeed a standard MOT?

Think the inductance of my primary needs to be lowered by say using a thinner guage wire but keeping the same frequency?  Looks like that would raise my Q value too. 

Is there a way to verify tube life without a "tubetester?"  Is it advisable to measure the annode of the tubes at a low setting on a variac?  My thought was if im applying voltage X to the MOT that the Voltage coming off the annode should reflect that at a specific higher voltage. Is there a formula for verifying that??

Thank you. 

Simon
(Go Packers!)

Begin forwarded message:

> From: Simon <elmontare@xxxxxxxxx>
> Date: September 21, 2012, 7:31:54 PM CDT
> To: Tesla Coil Mailing List <tesla@xxxxxxxxxx>
> Subject: Vttc video and math
> 
> Hello all again, 
> 
> I got side tracked with stuff but im back to this problematic vttc. Diodes and caps all check out same with continuity. Im thinking its a tube problem as they have probably been abused by an amateur coil as this and they are the only component i havnt checked. Total run time on them about 4 hours (not continuously). Id take constructive critisism on anything you see (math or physical). This is my first vttc. SG coils are so much easier to understand. 
> 
> 
> 
> This is a one minute video just going around the coil as an overview of the connections. (There are a few other related videos of it when it was working if you are so inclined). Some things are clearly temporary - grid and primary spacing and wire length on the tap wires. 
> 
> http://youtu.be/hdgsmATqGwo
> 
> 
> Secondary coil - 
> Radius - 2.25"
> Height - 15.25"
> Turns - 851
> Wire diameter - .0159
> 
> Topload - 4" sphere 
> 
> Topload + secondary - 366khz
> 
> 
> Primary coil -
> Radius - 3.625"
> Height - 4.6"
> Wire diameter .0808
> Turns - 21.3
> Primary capacitor - .0025uF
> Inductance - 75uH
> 
> 
> Grid coil -
> Radius - 3.625"
> Height - .220"
> Wire diameter - .0159
> Turns - 12.2
> Grid capacitor - .0025uF
> Resistor - 1kohm 100w
> 
> 572b vacuum tubes -
> 6.3V
> 4A
> Max voltage - 1200v
> Max current - 210 mA
> (4A 100VA fillament supply for 4 tubes in series). 
> 
> 
> Math was never my friend...
> 
> R = 5000v/4(.2*4) = 1562.5 ohms
> 
> X = 2*Pi*366000*(75/1000000) = 172 ohms
> 
> Q = 1562.5/172 = 9.0
> 
> (With a low Q could i just have not hit the sweet spot with coupling adjustments??)
> 
> Missing anything??
> 
> Thank you for anymore input :)
> 
> Simon
> 
> 
> 
> 
> 
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