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Re: [TCML] SRSG "sputter"
Hi Joe,
Is it possible for you to disconnect you're primary coil and just run the gap on you're capacitors alone? That way you could eliminate any issues beyond the spark gap if there may be any.
Brandon
On Jul 8, 2010, at 5:49 AM, Gary Lau <glau1024@xxxxxxxxx> wrote:
> Hi Joe,
>
> The sharp, cracking sound you describe sounds like something equivalent to a
> safety gap firing due to overvoltage and bad phasing - something that
> definitely needs fixing. If it's not in the safety gap itself, you'll need
> another pair of eyes at a different vantage point to spot the source of the
> discharges. For the arcs at the outer edge of the primary - are they
> between the primary and strike rail? But the location of the sounds is
> secondary to the underlying problem of why you're getting an over-voltage
> breakdown in the first place.
>
> Perhaps the phase of the gap is just very far from where it should be and
> beyond the range of the Freau adjuster? Maybe try rotating the motor or
> disk 45 degrees? What you should see is that as the adjuster Variac
> inductance increases and the phase moves later in time, the spark length
> grows until it abruptly goes to pot and the safety gap fires. BTW, I think
> the word "dwell" has no place in this discussion; dwell refers to the amount
> of time that contacts are closed, usually in the context of automotive
> ignition systems. We're varying the phase of the gap firing, not the
> duration of the firing.
>
> Just to be certain - your motor is 1800RPM? I don't think that
> primary/secondary tuning is a factor in this problem. I don't think a small
> angular error in the disk electrodes would do this either.
>
> I didn't understand what you saw when you adjusted the phase - "that just
> pretty much lengthens or grows the signal intensity". Are you certain that
> your motor is synchronous and that the adjuster is working? Have you tried
> taping a magnet to the shaft and scoping a pickup coil to determine the
> range of adjustment? It's easy to put a too-heavy rotor assembly on a small
> motor and have it unable to run synchronously.
>
> Regards, Gary Lau
> MA, USA
>
>
>
>
>
> On Wed, Jul 7, 2010 at 10:50 PM, Joe Mastroianni <joe@xxxxxxxxxxxxxx> wrote:
>
>> Hi All,
>> Ok, while I'm awaiting my parts from McMaster Carr to do my next version of
>> the SRSG, and propeller gap, I'm still fiddling with this little 4" wheel I
>> have.
>>
>> What I'm noticing is that at below 1/2 voltage on the variac, the gap is
>> happily firing, and things are calm and sparky. When I go to about 2/3
>> power, I start getting a sharp crackling from the area of the gap itself.
>> Sometimes the safety gap on the SRSG fires, and sometimes it doesn't - but
>> if I go even higher on the voltage, my Terry Filter safety gap goes off so I
>> shut down. Sometimes, the none of the gaps fire and I get a quick arc in
>> the vicinity of the outer turns of the primary.
>>
>> For grins I turned on the fan again I had blowing on the gap, and that
>> seems to have no effect, positively or negatively. I tried adjusting the
>> gap itself between the rotating rods and the stationary rods, and smaller
>> gap seems to be better than larger gap, but I still get the "sputtering".
>>
>> I have tried adjusting the dwell with the Freau adjuster, but that just
>> pretty much lengthens or grows the signal intensity, and as the voltage gets
>> up there, the sputtering starts again.
>>
>> Definitely cannot run at full power.
>>
>> I have tried tightening down on the collars that hold fast the rotating
>> electrodes by squeezing them with a vice grip to assure contact with the
>> copper ring on the back and then tightening the set screws, but there seems
>> to be no effect there.
>>
>> I'm wondering if I could have a "timing" issue in that the electrodes may
>> not be precisely 90 degrees apart - perhaps a fraction or a degree off,
>> depending. My protractor method could have been imprecise.
>>
>> ANy thoughts would be appreciated. Or I wonder if my tuning of the contact
>> to the primary is still off by some amount of a full turn....
>>
>> Cheers,
>> Joe_______________________________________________
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>> Tesla@xxxxxxxxxx
>> http://www.pupman.com/mailman/listinfo/tesla
>>
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