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Re: [TCML] Pre-Launch Prep Procedure



   Hi Mike,

When first started my 4.5" 15k60ma srsg, the safety gaps would fire and got some massive rail strikes at 80v-120v in.  After getting srsg firing at the right place/time those unwanted pops ceased.  I still play with the phase shifter while running and if the srsg gets too far forward or behind the peak the safety gaps go wild.   I made a timing light with some small led's and got it close.  The set up was crude but found the initial firing positioning of propeller was way off.  There are a number of sites in archives for examples to set the srsg.  I am using a 1/3hp motor, modified to run 1800rpm spinning a .25"x8" tungsten propeller with 4 stationary contacts with adjustable tungsten inserts.  This gives 120 bps.  
    Sounds like you are adjusting safety gaps correctly , it's how mine are set. Hope you post some pictures, unlike me with 2 great running TC's and can't get it together to post pic's !

                                                                                                                                                                                                            Bob



________________________________
 From: W5als <w5als@xxxxxxxxx>
To: Tesla Coil Mailing List <tesla@xxxxxxxxxx> 
Sent: Friday, July 12, 2013 6:16 PM
Subject: Re: [TCML] Pre-Launch Prep Procedure
 

Hi
    On my 6 in coil when I take it out of tune the safety gap would do that but
not at 50 volt, but when I play with the spark gap and got it to open it did
What you are saying at 75 volts. Your spark gap may be to far apart.
Just my thoughts but there are other things that can cause this problem too.
Alton

Sent from my iPad

On Jul 12, 2013, at 3:50 PM, Mike Gray <graymp89@xxxxxxxxx> wrote:

> NST is 10kV 50mA, and my cap is designed to approx 41nF. However I have no
> way of measuring it so I can't be sure. My multimeter says it can measure
> capacitance but I can't figure it out, I think it's more a gimmick selling
> point than a real measurement function. The 41nF is the optimum larger than
> resonance value for a sync gap, according to TeslaMap. My cap array is 7
> strings of 8 of these:
> 
> http://media.digikey.com/pdf/Data%20Sheets/Kemet%20PDFs/PHE450SD5470JR06L2.pdf
> 
> 
> On 12 July 2013 19:59, Yurtle Turtle <yurtle_t@xxxxxxxxx> wrote:
> 
>> What size is your NST and cap?  You may be getting resonant rise, in which
>> case your safety gap is doing its job.
>> 
>> 
>> 
>> 
>> ________________________________
>> From: Mike Gray <graymp89@xxxxxxxxx>
>> To: Tesla Coil Mailing List <Tesla@xxxxxxxxxx>
>> Sent: Friday, July 12, 2013 1:36 PM
>> Subject: [TCML] Pre-Launch Prep Procedure
>> 
>> 
>> Hi all. I'm having some trouble sorting out the correct pre-launch
>> preparation, specifically the Terry safety gap. What I currently believe to
>> be correct is this. In order to set the safety gap to just wider than the
>> max arc width the NST can produce, I first of all disconnect everything
>> else from the safety gap except for the NST. I then narrow the safety gap
>> so that it fires when the NST is fired up. I then gradually widen the gap
>> whilst at the same time firing up the NST, looking for the point at which
>> the NST can no longer produce an arc between the gaps. When I get there, I
>> leave the safety gap in that exact configuration for TC operation.
>> 
>> Trouble is, when I then go to energise the TC itself with everything
>> connected up again, the safety gaps fire when I'm at around 50-60% on the
>> variac. I can't understand how this happens!
>> 
>> So I thought maybe it's best to set the safety gap width with the rest of
>> the TC hooked up rather than in isolation. But then what to do with the
>> main gap (SRSG)? I've tried removing just the SRSG, and with the rest of
>> the TC hooked up try to set the safety gap width. In this case it started
>> to fire less frequently and with louder arcs each time I made it wider, and
>> this didn't sound right so I stopped. Thought it best to ask for advice
>> before I explode something...!
>> 
>> So what's the best way to set up the safety gap?
>> 
>> Cheers guys.
>> _______________________________________________
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