RE: Trigger Gap Controller Design??

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

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

Hi Gary,

Those resistors also add about $30 to the cost too :-(

My dimmer has all the electronics inside a single TO-220 device.  I am not
sure I can modify it as you suggest but I'll look into it.  I think there
is the variable resistor/switch, a cap, and a choke coil.  I'll have to
check into it...  Any way to get rid of the resistors would be a giant help!!

Cheers,

	Terry

At 09:23 AM 8/2/2001 -0400, you wrote:
>Blowing 400 Watts on hot resistors is a shame.  Couldn't the dimmer circuit
>be modified so that the R-C circuit that triggers the diac is placed across
>the incoming H & N lines?  It would mean breaking the connection from the
>dimmer cap to the output terminal, and bringing it out to a 3rd terminal
>that goes to the "other" mains lead that goes to directly to the coil
>terminal.  While it means performing minor surgery on the dimmer, it avoids
>the need for power resistors or lamps.
>
>Gary Lau
>MA, USA
>===================================================
>
>
>Original poster: "Terry Fritz" <twftesla-at-qwest-dot-net>
>
>Hi All,
>
>Here is what I have come up with for a triggered gap controller so far.
>
>It is highly experimental, not well tested, zero guarantees....
>
>It seems to have very low noise, full phase control, and might not blow
>itself and everything else up.  I don't suggest anyone go out and make it
>at this point but if your experimenting or would like to make any
>suggestions, here it is as of 8:18pm ;-)
>
>http://hot-streamer-dot-com/temp/TGap1.gif
>
>The filter and dimmer circuit can be separate so they can be used for other
>fun things.  That helps to justify the cost a bit.
>
>I seem to need to dual stage filter even if it does cost $28.  May those
>less concerned about RFI could do without it but it is easily worth the
>cost to me.
>
>The two resistors could probably be replaced with a big light or other ~400
>watt pure resistance.  They run about $14 each from DigiKey.
>
>The 2uF cap is a AC motor run type or perhaps a few paralleled capacitors
>from DK.
>
>I had some 15kV 500pF door knobs here but a "real" design needs a good
>stable source for such a part.
>
>Any comments or suggestions are welcome.  Unfortunately, even though it is
>basically seems to be working well, it is fairly costly if one uses new
>parts.  The resistors will also draw about 3 amps off the AC line which is
>just waste heat.  However, they sure make it run nice!  No great though
>into the reliability or fault handling yet...
>
>It is really not too different than what people are using now with the
>exception of the power resistors which are probably needed for a stable and
>wide range of dwell control which a triggered gap needs.  The top and
>bottom circuits can also be widely separated for a nice remote control with
>the phase adjustment at the controller.
>
>Again, it is definitely not ready for anyone to go out and make yet, but it
>is getting there...
>
>Cheers,
>
>	Terry
>