Hendershot Replications

[mlurye]

Did you compare one layer and double layer capacitors on your Hendershot tank ?

Standard caps do not affect HF resonance much, with double layer there is much better response in tuning.

[NOMDI]

capacitor

I can tell you one thing, test it with standard capacitor and build one and you definitely will see the difference.

Did you compare one layer and double layer capacitors on your Hendershot tank ?

[mlurye]

Another interesting fact is that Moray was working in 5MHz range. And Hendershots coil resonates in a range of 5MHz. This 2 devices got something common.

[mlurye]

I can tell you one thing, test it with standard capacitor and build one and you definitely will see the difference.

[NOMDI]

double layer capacitor

I just realized WHY there are 3 plates:

Foil A : 91.25 inch x 2.75 inch
Foil B : 40 inch x 2.75 inch
Foil C : 40.375 inch x 2.75 inch

The capacitance between foil B and A will be one
capacitor .. the capacitance between foil C and A
will be a second one. They are essentially
connected in series via foil A.

Notice that the width of B and C + a gap of 3/4 inch
still fall short of the length of foil A.
I suppose there is suppose to be some overhang there
to be conservative ... about 5 inches either side.

Hendershot appears to have been using a
"double-layer capacitor" approach:

Electric double-layer capacitor - Wikipedia, the free encyclopedia

I've read somewhere that nowadays double layer capacitors are used to reach very high value capability. Hendershot claims a 7.8 nF which is very low. If he used the handmade capacitor with this technology, using the foils (that we can't see on any picture, of course) in the serial way, we can speculate he did it only to get a very high voltage capacitor. It seems to be logical because the LC cell is made to be tuned a the resonance point, which means high voltage pikes. Can we suspect that every replication made with a single layer capacitor (made of paper which is not as good as actual plastic films for insulation) has "dead born" capacitors ?

I also guess that this could explain the value of 1.3 mF (we've seen in his son document), which could be in fact 13 nf, almost twice the value of the 7.8 nF he could have first experiment with a parallel double layer capacitor...

[morpher44]

Dan A. Davidson

In reading the Don Smith thread, I saw a mention of
Dan Davidson's patent.

Wow! This looks similar to stuff Hendershot had done.

Acoustic-magnetic power generator - Google Patent Search

Dan's patent mentions these:

Magnetic motion electrical generator - Google Patent Search

Electromagnetic convertor with ... - Google Patent Search

[morpher44]

7.8nF hand-made caps

I just realized WHY there are 3 plates:

Foil A : 91.25 inch x 2.75 inch
Foil B : 40 inch x 2.75 inch
Foil C : 40.375 inch x 2.75 inch

The capacitance between foil B and A will be one
capacitor .. the capacitance between foil C and A
will be a second one. They are essentially
connected in series via foil A.

Notice that the width of B and C + a gap of 3/4 inch
still fall short of the length of foil A.
I suppose there is suppose to be some overhang there
to be conservative ... about 5 inches either side.

Hendershot appears to have been using a
"double-layer capacitor" approach:

Electric double-layer capacitor - Wikipedia, the free encyclopedia

[mlurye]

Yes transformers are in. I don't have solenoid, so can not try with it.

[morpher44]

impedance...

Actually all coils are connected according to schema, only I replaced load and buzzer with LEDs. Interesting part is that sweet spot at exact 5000000Hz.

@mlurye
Certainly the solenoids would bring that down a bit.
Also, do you have the 5:1 transformers in circuit?
They don't like high frequency.

[mlurye]

Actually all coils are connected according to schema, only I replaced load and buzzer with LEDs. Interesting part is that sweet spot at exact 5000000Hz.

[morpher44]

which coil?

I was playing with coil, and found that it resonates at multiple spots and one of them ~5MHz. I'm having hard time to tune it at 5MHz.

Which of the 4 coils on the Hendershot cylinder are you referring too?

5Mhz does seem a tad high.
The self resonance of these 4 different coils will be
lower than that probably.

[mlurye]

I was playing with coil, and found that it resonates at multiple spots and one of them ~5MHz. I'm having hard time to tune it at 5MHz.

[morpher44]

gravity sucks...

I left a sketch of an solenoid armature motor at the bottem of page four. I agree that oscillations might occur spontaniously, and that if the operating amperage were to drop while running the solenoid fluctuator motor, it would be a good indicator, and the armature could be be freed to flutuate on it's own after power´s cut off. I think motoring into the zone to fish for self oscillation would allow for testing by a drop in amp draw to help locate it.

Yes... interesting.

Find the sweet spot with this magnetic stuff might
be very difficult indeed.

One thought about going up-down instead of left-right is that
when you have to go up, you have to expend quite
a lot of power to fight gravity. Down ... no problem .. let it fall.
So there is an asymmetry in that orientation which might
not lend itself nicely to a sine-wave.

Left-right, on the other hand, might be easier to acheive
a sort of symmetry and balance.
I think we are still very much earth bound and always
have to consider gravity ..

The Wesley Gary thing is kinda cool in that it does go left-right
and up-down. Like a see-saw.

If the bar, in the Hendershot device, is to be held between
the magnet and the solenoid, without touching either
(and I'm not sure that is the way yet), then
ideally the bar would float in some very low friction medium.

Doorbell manufactures use a sort of rubber washer to hold
the bar -- not unlike a xylephone.

[morpher44]

The human ability to tune...

One thing that made the radio so compelling a hobby in the
early 1900s was the thrill of building something from scratch
with oatmeal cartons, wire, crystals, home made salt water
capacitors, antennas across the roof and yard, ground pipes.
It was MAGIC!!!

Another very human aspect of old time radio was the notion
of "tuning". You felt so SMART when you could tune in some
very hard to receive distant station ... achieving that
very difficult resonance value which might be lost by the slightest
mussel twitch.

The Hendershot device is very interesting because there
are TWO coils to tune -- a left and a right.

I performed a pretty interesting experiment tonight.
I have two 216uH 5 inch diameter basket weave coils
that I made for some earlier experiments.

I connected one up to channel 1 of the scope.
I connected the other up to channel 2 ... and
put the scope in X/Y mode.

These coils w/o any other components, receive RF up
and down the spectrum ....

On the scope I see a nice 45 degree line because
both coils receive exactly the same RF signals
at exactly the same time.

Now for the fun "human tuning" part.

If I place these coils near each other -- say
3 inch appart or less -- and move my hand
near one ... or touch one ... the
capacitance I can add will boost the amplitude.
That boosted EMF in the first coil is easily received
by the other coil if they are near.

I find that I can apply different amounts of pressure
to the wires, etc. and actually alter not only
the signal strength .. but also the PHASE between
the two coils.

So by watching the scope ... in a sort of biofeedback sense,
I can manipulate the situation to increase the voltage
to both coils and the also get the phase to be exactly
90 degrees different, producing a CIRCLE!!!

See the attached image for Lissajous patterns.

So in the Hendershot design, I would not underestimate the
human ability to TUNE in the exact relationships ...
between phase and voltage needed to achieve
resonant oscillations.

[morpher44]

on the subject of exact replication...

I would advise you to build exact replica of Hendershot device, it would be the best way to understand how it works. Even if it doesn't pick up anything, you can feed signal in and trace it.
I did look at other devices and I do believe that we have the best chance with Hendershot device. It has the most complete schema and good guide on how to build it.

So far I have been studying a very small subset of the full
circuit to get an understanding of how things could work ..
and to help me make decisions about further construction.

There are so many things I still don't know ... and I have a shoe
string budget and not a lot of time (day job) ... so progress is slow.
I'm hoping for others to come along and attempt replications in
different ways so that we can compare notes.
If I use ferromagnetic cylinders and someone doesn't, will we
see a difference.
Can I get results with a 5 inch diameter just like a 5 15/16 diameter?
Do the 40/80 MFD cap value matter ... or can 30/100 MFD work too?
How exactly is the bar - magnet - solenoid to be built cheaply?

Yes I know progress seems slow ... but remember that
Hendershot worked on this from 1928 to 1961 -- his
entire adult life.

I'm also very surprised we are not hearing from others who
have already attempted the Hendershot device.
There are some folks out there who have already tried it.
Their notes would be invaluable.

Please share if you dare!!!