Re: OLTC update - Poor seconadry Q

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Malcolm Watts by way of Terry Fritz <twftesla-at-qwest-dot-net>" <m.j.watts-at-massey.ac.nz>

Hi Bart,

On 30 Aug 2002, at 21:59, Tesla list wrote:

> Original poster: "Barton B. Anderson by way of Terry Fritz
<twftesla-at-qwest-dot-net>" <tesla123-at-pacbell-dot-net>
> 
> Terry,
> 
> Tesla list wrote:
> 
> > Original poster: "Terry Fritz" <twftesla-at-qwest-dot-net>
> >
> > So... I don't know if it is the SonoTube, surroundings, proximity effects,
> > plastic wrap coating...  Have to test some things...  A small chance it
> > could be the anti-parallel diodes...
> 
> I think none of the above, but rather the secondary itself. I would bet the Q
> of the secondary by itself is pretty low.
> 
> > Of course, ideas on how I can fix this are more than welcome :-))
> 
> Rewind a secondary with less turns and larger wire. Fres will tripple
(not sure
> how tied into 0.47uF you are with the IGBT current). Of course, with all the
> work you put into this project already, I hope it's something else.

That is exactly the problem. The large Cp is causing all sorts of 
design havoc with the secondary which is really far too small to give 
low losses at 30-something kHz.

Regards,
Malcolm
 
> BTW, if you were to model the secondary in JavaTC (since it was mentioned in
> another post), here are the input parameters for your coil:
> 
> Sec Diam = 10.75
> Sec Length = 41
> Bare Wire Diam = 0.0126
> Insulation = 0.001
> Spacing = 0.000255
> Toroid Major = 24
> Toroid Minor = 6.5
> Sphere Diam = 0
> Top Load Reduction = 36.3
> 
> Here are some of the main outputs JavaTC identifies:
> DC Resistance = 507.53 ohms
> Inductance = 480.13 mH
> Self Fres = 52.4 kHz
> Skin depth = 0.014 inch
> Loaded Fres = 38.21 kHz
> Total Capacitance = 36.14pF
> 
> Take care,
> Bart
> 
> http://www.classictesla-dot-com/java/javatc.html
> or
> http://www.classictesla-dot-com/java/javatc92.html
> The bottom link is beta version 9.2
> 
> 
> 
> 
>