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Re: [TCML] Notes on first SRSG...
FWIW -
My own personal observations based on my system - haven't used a
phase-delay on my SRG, did it the old-fashioned way, incremental
adjustment of motor angle in the cradle. But you CAN tell when you are
firing at the Vpeak on the caps by the sound. You should hear a stable
firing noise and the secondary discharge will be almost fluid in it's
movement.
One thing with the gap distance setting - narrower settings DO fire at
lower voltage, also however, higher input voltages (correspondingly higher
Vpeak on the caps) will cause the gap to fire EARLIER in it's rotation - a
> I'd like to amplify one of the points John made below that I failed to
> mention in my reply. Even with a well-made Freau phase adjuster, it is
> still necessary to make an initial trial and error ballpark mechanical
> adjustment between the motor shaft and disk or motor and cradle. Any
> Freau
> adjuster has a limited range and it needs to be somewhat close.
>
> Please post some photos, as there are any number of other issues that can
> be
> a factor that we just have no visibility into. Also, more info on your
> motor and gap arrangement may be useful.
>
> Regards, Gary Lau
> MA, USA
>
> On Sun, Jul 4, 2010 at 11:36 AM, <futuret@xxxxxxx> wrote:
>
>> Joe,
>>
>> Are the rotary gaps set close enough together for reliable firing? If
>> the
>> electrode spacing
>> is too wide, the rotary will only fire at a high variac setting. Of
>> course
>> if the electrodes
>> are tungsten and are set too close they can crash and break off. In any
>> case
>> the coil should begin firing at a lower variac setting I would think.
>> 25nf
>> should be
>> OK for a 15/60 NST. 25nf should not be too large to fire reliably.
>>
>> The phase setting for the SRSG can only be set by adjusting for longest
>> sparks.
>> It cannot be adjusted using a scope because the firing timing depends on
>> the
>> exact characteristics of the NST and the cap value. The phase setting
>> should
>> not be set without the resonator in place. That can damage the caps and
>> won't
>> work anyway. You may be able to get in the general ballpark range using
>> a scope, but I didn't bother in my own work.
>>
>> The phase controller gives only partial phase range. If you get best
>> results
>> at the end of the phase controller variac range, then you'll need to
>> rotate
>> the motor itself some in it's mounting cradle, or shift the rotor
>> relative
>> to the
>> motor shaft to get the proper range. Of course the phase setting will
>> be
>> very different for the 25nf cap and for the 18nf cap. This may be why
>> you
>> got better results with the 18nf cap (or part of the reason).
>>
>> If you watch the rotary spinning under fluorescent light, you'll be able
>> to
>> see if it's truly running in sync (just the rotary alone, no Tesla coil
>> firing).
>> The light pattern will rotate if you lower the rotary voltage so it
>> drops
>> out
>> of sync, and you can hear the hunting sound when it's almost syncing
>> as you raise the voltage. (I'm referring to the motor voltage not the
>> phase shifter variac setting). You can just unplug the motor and you'll
>> see the light pattern start rotating, then freeze when you plug the
>> motor back in and it syncs. Some people have a very very very hard
>> time seeing these patterns under fluorescent light however.
>> (Maybe you did all these verifications tests already).
>>
>> The sound of the system should be 120 BPS, not 60 BPS. You should
>> be getting 56" sparks or so if you're using a step up type variac
>> (140volts).
>>
>> I'm surprised the variac has to be turned up so high for the static gaps
>> to fire. Maybe the static gaps are set too wide? I'm assuming you
>> have the coil tuned correctly at the primary tap. I didn't verify using
>> JAVA TC or anything. You'll probably need to tune outward by a turn
>> or two more than JAVA TC suggests, because JAVA TC doesn't
>> account for spark loading effects on the tune point.
>>
>> John
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>> -----Original Message-----
>> From: Joe Mastroianni <joe@xxxxxxxxxxxxxx>
>> To: Tesla Coil Mailing List <tesla@xxxxxxxxxx>
>> Sent: Sat, Jul 3, 2010 11:02 pm
>> Subject: [TCML] Notes on first SRSG...
>>
>>
>> HI All,
>>
>> I got my first SRSG running today. Some notes, and maybe you
>> experienced
>>
>> fellows can enlighten me on the phenomena I'm observing --
>>
>>
>>
>> - Running a 15/60 NST. 17 turns of 1/4" x 1/4" refrigeration line as
>> primary.
>>
>> 22" tall, 30GA, 4" dia secondary. 25nf MMC (3 banks of 18 0.15mf by
>> 2kV).
>>
>> Tophat is an 18" x 4.5" spun toroid. Using 2 variacs - one in John
>> Freau's
>>
>> phase-shift configuration, and one for primary power.
>>
>>
>>
>> - Experimented running with the static gap and 25nf, instead of 18nf on
>> the
>>
>> MMC. With 25nf on the MMC the variac has to be an nearly 120V for the
>> static
>>
>> gap to fire. It's kind of all or nothing. Turning on the primary is
>> around
>>
>> the 13th turn in this configuration
>>
>>
>>
>> - Switched to the rotary gap - difficult to "tune" the SRSG phase in
>> this
>>
>> configuration, because you either get it to fire, or not, with max power
>> on
>> the
>>
>> power variac. Lots of trial and error.
>>
>>
>>
>> - Tried tuning the phase without the coil resonator connected to the
>> SRSG.
>> Sort
>>
>> of works...think I got it firing right.
>>
>>
>>
>> - Took the 3rd bank of the MMC off - and lowered the total tank cap to
>> 18nf.
>>
>> Now the gap fires at lower voltages, and I can tune the phase. Though
>> now
>> I'm
>>
>> worried I should switch back to the 25nf capacitance to avoid blowing
>> something.
>>
>>
>>
>> With 18nf capacitance and the SRSG rotating in what I think is a
>> reasonable
>> sync
>>
>> phase with utility power - I'm getting some really great results.
>> Sparks
>> are
>>
>> bright and "mean" sounding - full of what I presume to be 60hz buzz.
>>
>>
>>
>> Is there any reliable way to tune the phase of the SRSG with a scope (or
>>
>> without) - without having to rig up some kind of optical strobe sensor?
>>
>>
>>
>> Thanks to all for the help!
>>
>>
>>
>> Joe_______________________________________________
>>
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>>
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>>
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>>
>>
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