[Prev][Next][Index][Thread]

Re: Light Bulb Experiment (Followup)



Tesla List wrote:
> 
> >From bert.hickman-at-aquila-dot-comSat Sep 28 10:13:58 1996
> Date: Fri, 27 Sep 1996 23:24:14 -0700
> From: Bert Hickman <bert.hickman-at-aquila-dot-com>
> To: tesla-at-pupman-dot-com
> Subject: Light Bulb Experiment (Followup)
> 
> Here's a "Light Bulb Experiment" and toroid-ground discharge update:
> 
> Previously, I had used various sizes and wattages of light bulbs placed
> in series with the corona current path. These lights unexpectedly
> "dimmed" when passing heavier toroid-ground discharge currents. Dave
> Huffman and Robert Stephens theorized that these higher current
> discharges were bypassing the filament path due to unseen arc-overs
> between the lamp-base leads. And after a few more experiments, I
> concurred, but had no direct proof.
> 
> I just tried a slightly different experiment using a 100 Watt tungsten
> halogen lightbulb. This bulb is about 2" long x 1/4" diameter, with the
> filament going the length of the bulb, and having a ceramic & metal
> termination at each end. This particular construction prevents any
> flashovers, forcing both the corona and ground surge currents to flow
> through the filament. Because of the larger filament wattage, I was only
> just barely able to light the bulb when running streamers to air through
> the filament. However, once toroid-ground discharges began between the
> free end of the lamp and a grounded wire 42" above, the filament began
> to glow fairly brightly.
> 
> This helped confirm that the previously observed dimming associated with
> Mazda-based lamps was indeed an artifact due to the heavy current arcing
> around and bypassing the filament. I very carefully observed the average
> brightness of the bulb under the heavy-discharge condition while running
> the coil at maximum power. I then connected the same bulb to a variac
> and an AC ammeter to estimate the average current necessary to light the
> bulb to an equivalent degree. This level was reached at about 400 MA,
> implying that the lamp was seeing an "average" current level of about
> 400 MA during the ground discharges (sort of like a hot-wire
> ammeter...).
> 
> Further measurements with a storage scope showed that each
> toroid-to-ground discharge removed virtually ALL of the energy in the
> Primary/Secondary system in a very short time. There was no further
> ringdown, or any other activity until the next "bang". Each discharge
> occurred near the first peak of secondary voltage (i.e., during the
> first energy transfer/"Bang"). Each high-current discharge actually
> consisted of an exponentially damped 10-20 MHz current, with virtually
> all of the energy being dissipated in about 1.5 uSec. At full power, the
> primary gaps fire 3 to 4 times every half cycle, or between 360 and 480
> PPS. For analysis purposes, an average rate of 420 PPS will be used.
> 
> Using 420 PPS, with each toroid-ground current surge lasting only 1.5
> uSec, the total time "ON" time per second is about 420 x 1.5 uSec or 630
> uSec, implying a duty cycle of only about 0.063%. The toroid-ground
> current peaks which would have to flow to "average" 400 MA can now be
> estimated: Isurge=(0.400)/(630x1e-6) or about 635 Amps(!). However,
> since the actual current surges are exponentially decaying during each
> 1.5 uSec shot, the actual current peaks are probably significantly
> greater than 1000 Amps(!).
> 
> This explains why these discharges look so mean and evil... they ARE!
> 
> As always, flames, brickbats, and snickering are always welcomed.  <:?)
> 
> Safe (and rubber-booted) coilin' to ya!
> 
> -- Bert --

Bert
This is neat stuff but I think one more measurement needs to be made. I
have a major problem in believing that the filament will actually take a
1000 amp pulse. I think a controlled test dumping a 1000 amp pulse of
the prescribed 1.5 usec  pulse duration thru the lamp to see if the lamp
will actually live would help to bolster your conclusions.

Skip