RE: srsg idea to prevent losses

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

Original poster: "Terry Fritz" <twftesla-at-qwest-dot-net>

Hi Gary,

Both of my coils have just about zero quenching :-))  They conduct until
the current is just gone...  The big coil does loose a little due to
primary to secondary "sloshing" but the small coil is designed to expend
all of it's power to the streamer during the first notch.  There is nothing
left to slosh back to the primary.  It has lower Q and all to do that,but
it seems to work very well.  Solid state spark gaps can provide "perfect"
switching too like the proposed contact gap.  Of course,they can also open
back up to microsecond accuracy...

The idea of submersing a contact type gap in oil is intriguing.  Maybe
putting it all in on heck of a vacuum too...  But the heat dissipation in
the gap and motor would be about zero in a vacuum...

Much to ponder...

Cheers,

	Terry


At 03:42 PM 3/20/2002 -0500, you wrote:
>Actually, it IS necessary to have a spark as the conductor in a spark gap.  
>It has to do with quenching, or when the gap stops conducting.  In a spark 
>gap, conduction ceases at one of the primary notches, when all of the 
>primary energy has been transferred to the secondary side.  A spark "knows" 
>when to stop conducting by virtue of the gap current, when it reaches a 
>minimum.  A mechanical contact's on-duration is dictated strictly by the 
>mechanics of the design and it would be nearly impossible to design it so 
>that the switch opens with microsecond accuracy just at a primary notch.  If 
>the on-time was too long, the energy would slosh back and forth between the 
>primary and secondary, wasting energy in the gap and other loss mechanisms.
>
>Of course, the fact that the contacts will arc in the "normal" fashion well 
>in advance of mechanical closure means that the above is purely academic.  
>Also, rotary contacts spinning at 1800 or 3600 RPM with zero clearance 
>between them will guarantee an electrode crash.
>
>Regards, Gary Lau
>MA, USA
>
> -----Original Message-----
>From: 	Tesla list [mailto:tesla-at-pupman-dot-com] 
>Sent:	Wednesday, March 20, 2002 2:55 PM
>To:	tesla-at-pupman-dot-com
>Subject:	Re: srsg idea to prevent losses
>
>Original poster: "Terry Fritz" <twftesla-at-qwest-dot-net>
>
>Hi Colin,
>
>Since the voltage across the gaps is high, they will tend to arc over about
>1/4 inch before the contacts actually touch.  Depending on the speed of the
>electrodes, the firing process my be all finished by the time the contacts
>actually do touch.  Maybe like 0.0003 second.  Even a fast 3600 RPM gap
>will only move the electrodes 6.5 degrees in that short time.  So I think
>early firing from high voltage arcover will be a big problem.  However, it
>really can't hurt and may be better anyway as far as losses go.  The actual
>"spark" in the gap is totally unneeded and only wastes power.  The problem
>is it is hard to get rid of ;-)
>
>Cheers,
>
>	Terry
>
>
>At 04:09 PM 3/20/2002 +0000, you wrote: 
>>hi all,
>>        im concidering an idea with my rotary gap and would like to run it 
>>by you all
>>now it could be totally stupid or it could work
>>let me know what you think
>> 
>>im going to run my gap without spark gap but instead have the rotor 
>>electrodes touch a spring loaded contact so it brushes by it when running
>>i have achieved the actual building of this unit but just wondered whether 
>>it needs to spark to work
>> 
>>i was hoping this would reduce losses in the spark
>>i am a newbie to all this only 4 months and have two coils my best putting 
>>out 4'
>> 
>>please let me knoew what you think of this idea
>>many thanks 
>>colin haeth
>> 
>>
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