Re: [TCML] Magnifier topics

[futuret@xxxxxxx]

 BTW, when Lou Balint of PA did his magnifier experiments using a variable
C2 a number of years ago, he didn't find any particular setting that gave
longer sparks than the typical magnifier arrangement.  Although he
wasn't specifically looking at Antonio's modes, he did try a number of
variations of k, C, and L.  

I guess it remains to be seen if some particular critical arrangement
gives an advantage.  

Regards,
John

 


 

 

-----Original Message-----
From: Finn Hammer <f-h@xxxx>
To: Tesla Coil Mailing List <tesla@xxxxxxxxxx>
Sent: Thu, Feb 18, 2010 6:11 am
Subject: Re: [TCML] Magnifier topics


Antonio Carlos M. de Queiroz skrev: 
 
> I will try to find a reasonable design. Fixing C1, L1, and C3 > determines the other elements completely, once chosen the mode. 
> The question is then to chose an adequate mode, that results in > reasonable elements, voltages and currents. 
> How was the original secondary coil? It's self-capacitance contributes > to C3. I also need the initial voltage in C1 and the 
> maximum current that the spark gap equivalent can conduct safely. 
Original coil: 
389mH (measured Meterman 37XR) 
Diameter: 200mm 
Length:     860mm 
Toroid 100mm above top turn. 
 
Initial voltage C1= 1000V (1200V IGBT as gap) 
Gap has been known to pass 4500Apeak  :-) 
> 
> The biggest practical problems I expect to be the construction of C2 > and the insulation in the driver transformer. 
The starting point is voltage across C2. 
 
mrn6.exe predicts 125kV   =8-} 
 
10pcs. 4nF doorknobs under oil, or in a stick, with grading rings? 
 
I am concerned about how to measure the coupling, since the coil is a 50mm wide strip. 
Let´s assume that coupling can be expected to operate from middle of strip. 
In that case, a 250mm dia coil, 250mm long (nice and fat), where the bottom end is alignined with the bottom of the primary coil, produces k = 0.36 according to javatc. 
Insulation on L1/L2 yes, perhaps a problem. 
If 125kV across length of coil, then 50mm up of it, there is going to be 125/(250/50)=25kV 
Radial distance from top of primary coil to secondary =25mm resulting in 1kv/mm: not a problem per se, but perhaps in practical work.Perhaps a field shaping ring will be needed at the top of the primary coil, to suppress corona. 
> To give an idea of what can be a design, mode 3:4:5, with 50 pF for > C3, and adjusting the first 3 digits of L3 results in: 
> C1=15510.0000000000 nF 
> L1=    0.8599613153 µH 
> C2=  406.3492063492 pF 
> L2=   32.7600000000 mH 
> C3=   50.0000000000 pF 
> L3=  234.0000000000 mH 
> k12=     0.3504383220 
> Voltage gain:  556.9560126258 
> Energy transfer time:    42.9836 µs 
> 
> Antonio Carlos M. de Queiroz 
> 
> _______________________________________________ 
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> Tesla@xxxxxxxxxx 
> http://www.pupman.com/mailman/listinfo/tesla 
> 
 
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