To: tesla-at-grendel.objinc-dot-com (Nikola Tesla (Chip Atkinson))
Subject: Re: TCBOR
From: "SROYS" <SROYS-at-radiology.ab.umd.edu>
Date: Mon, 17 Oct 1994 16:59:15 EDT
>Received: from comm1.ab.umd.edu by csn-dot-org with SMTP id AA21036 (5.65c/IDA-1.4.4 for <tesla-at-grendel.objinc-dot-com>); Mon, 17 Oct 1994 15:03:24 -0600
> What were these adjustments?
The first thing that I did was to change my capacitor setup to what the
TCBOR group calls the "Equidrive" configuration. This configuration
has the spark gap parallel to the transformer and two sets of matched
capacitors symetrically placed in series on each side of the gap
running to the primary coil as shown below (P=primary supply, G=gap,
C1 = C2 = matched capacitors (note that Ctotal = C1/2), and L1= primary
coil). The caps must be identical(?), not just pretty close in value to
realize any benefits. This also means that if you currently only have a
single value capacitor, to run in this configuration you now need 4 caps
to get the same capacitance (2 on each side wired in parallel to
compensate for the fact that the 2 capacitances in series reduce the
total capacitance by a factor of 2).
NOTE: In the equidrive configuration, the caps will remain charged
since there is no DC path to ground to discharge them so they MUST
be discharged manually BEFORE making any adjustments (It's a good
idea to discharge them before any adjustments are made at any time...I
got zapped a day after I turned my coil off and the caps recharged
themselves enough to bite me).
| | |
P G L1
| | |
In the CSN, Tesla states that compared to the resonant frequency, if
you have a low break rate you should have a large primary inductance,
and if you have a high break rate you can use a small primary
inductance. I used the little neon light trick and saw that I was only
getting a single break per half cycle, so I reduced my gap, decreased
my primary capacitance by a factor of 2 and doubled the number of
primary turns I was using.
After making these changes, I was getting about 3 or 4 breaks per half
cycle and 7 more inches.
For the near future, I will up my capacitance again when I get a better
gap set up and increase my terminal capacitance so I can still use the
larger primary inductance. I'm also going to rewire everything with
thicker wires and try to reduce stray inductances by keeping all leads
as short as possible. I'll keep you posted.
Another thing mentioned in the "CNS Guide" (and other references) is
that your primary cap should be matched to your transformer. You
should have Cmax = It(377*Et), where Cmax = max capacitance you
should use (in Farads), Et = rms secondary voltage, and It = rated
secondary current. If your cap is much bigger than this, your primary
supply won't be able to charge it up properly.
Steven Roys (sroys-at-radiology.ab.umd.edu)