Mr Lester J Hendershot's magnetic generator.

[soundiceuk]

Hi, this company that sends me marketing media from time to time looks to be selling horseshoe neodymium magnets.

Win Magnetics Co.,Ltd

Web: www.winmagnet.com

Tel: 0086-(0)574-87405552

Fax: 0086-(0)574-87405558

Cell: 0086- 18858026663

Skype:Alvin.winmagnet

Add: Room 506,Unit 10,XinTianDi Plaza,YinZhou District,Ningbo City,ZheJiang China PR 315040


It has been suggested to me that Hendershot was using Radium. How true this is I don't know, but it sounds likely to me.


Best regards,

Paul

btw folks are falling for that really long video. I know some rich guy that was about to pay someone to build it. Not good. Luckily I saved him.

[thx1138]

Pierce Arrow energy box

Re your Tesla (top ten) link, strange that there was no mention of his Pierce Arrow energy box ! I think that what we read depends upon who is publishing !

The interview was 1928. The Pierce Arrow was 1931 or later. What I've read on it indicates it was a 1931 Pierce Arrow but that doesn't necessarily mean it was new and the year was 1931. So it could have been '32 or '33.

[john_g]

Can you share information on the magnet shown in post #173? Where you obtained it, overall size, space between poles, pole sizes, etc?

I'm putting together a parts list and am having trouble locating a suitable magnet. I can put together 10 pieces of neo magnets to make one but it's roughly $350 just for the pieces. That's more than half of the parts cost and I would like to get that cost down.

I did find some cloth covered wire that is 0.105" so that might have to do. The O.D. is not specified at the site but I left a message and they replied back with 0.105" O.D.
20 awg Solid Core, Cloth

Hi THX1138

You asked re the magnet-

Where you obtained it:

Given by a friend, it was ex railways, not sure what it was used for.

Overall size, space between poles, pole sizes, etc:

3" width,2" depth, 1 1/2" height. pole face 3/4" width x 1" height. Distance between pole edges 1 1/2"

Regards

John

[GSM]

Great to see the thread has moved on without me. Will catch up soon.
I ended up as an unconcious hospital emergency with kidney infection
( atmosphere or water supply bourne ? our skies here have been filthy ! ).

Just home, and I look forwards to catching up, but I'm very shaky-weak-shattered.

So life's kinda on hold at the moment, but I do hope to be back kicking ball with everyone shortly.

Stay safe folks;

Cheers ............... Graham.

[thx1138]

CapCoil calculations

Different capacitance values have been quoted, but there is no way the 96" long by 2.75" wide element mentioned could have had a capacitance value as low as the 7.8nF.

Hence I decided to use a web based capacitance calculator -
Tesla Coils - Capacitance Calculator

An inner core 5.25" dia. gives a length of 16.5", by 2.75 inches high for width.
For Kraft paper and first insulation layer I have estimated a 5 thou plate spacing.
For dielectric constant I have estimated and entered 3.5.
When the number of platesis 2, and the dimensions are in inches,
the estimated capacitance of the first core-cap turn came out as 0.007139uF.

Clearly this is in the ballpark of 7.8nF, and PROVES that the centre core itself must have been circuit connected, for otherwise, and without its own tag connection, that figure would not even have been measureable.

I started on that document to compare the different documentation on the Hendershot device and immediately ran into discrepancies other than connections. The doc in the Mar-Apr 1989 JBR,Pg25 drawn in 1963 by Edward O'Brian RE the Aho build shows the inner can as 3" tall. Going by Fritz Lowenstein's work on capacitances, the smaller of the plates has the most affect upon capacitance. The second plate can be very much larger without adding even 1% to the capacitance value. The innermost cylinder must, by definition, be the smaller of the plates if it is connected. I used the calculator you linked to above with the parameters given but changed the 2.75" to 3" as stated in Edward O'Brian's work and the result was 0.007788uF. which would be 7.788nF. That's not to deny that the wrapped foils are 2.75" wide but the wrapped foils being so much longer means that they don't have as much affect on the capacitance as the innermost cylinder.

Now that I have most of my materials list together I found another reason to justify using 3" rather than 2.75". In all of the photos I've seen the inner cylinder extends above the coils somewhat and if you add up the number of turns of each coil and the thickness of the wire used in each coil there is no way that the L1, L2, and L3 coils would be less than 2.87" which would cpmpletely cover all of the inner cylinder if it were 2.75" and none of the photos show that. In fact they all show the inner cylinder extending above the uppermost coil.

I also found out that PVC was first used as wire insulation around 1950 so it seems I've been chasing my tail searching for the 0.100" O.D. wire. That 2.87" height above comes from using PVC jacketed 20 AWG solid with an O.D. of 0.066" for the top 2 coils at 12 turns each.

All of that also depends on the assumption there is indeed a connection to the inner cylinder since it would have to be the smaller plate of the capacitor part of the CapCoil.

I'm wondering how you came up with the dielectric constant of 3.5 and the 5.25" diameter in your calculation.

I also found notes in the From The Archives of Lester J. Hendershot document by Mark Hendershot that are hand written by Lester J. that say ".0078 MFD or posibly 1.3 MFD (see notes Orig.)" Emphasis added. Page 45 of the PDF document.

One other thing on the CapCoil: I don't think it said anywhere that the foils were taken from a Pyramid 80/40 cap. The statement was a Pyramid TM58, but that might just be the the part number for the 80/40 cap. I'm not sure.

I did find a Pyramid 40/10 cap and it is on its way. Its not for use in this project but it can give us the thickness of the foil and paper when I disassemble it. That brings me to another thought - the electrolyte in the old capacitors was basically a salt solution and failing to completely remove the electrolyte may be what led to the rusting of the coffee cans. It could have leached through the 3/4" inch gap in the shorter foils to the inner paper around the inner cylinder.

More to come on materials list.

In the mean time here's an article you may find interesting: Magnetic vortex oscillator driven by dc spin-polarized current

[pjotterkjen]

More details, please

@pjotterkjen
I have not given up yet. I didn't expect it to work on the first try but I wanted to get an idea of what it would look like. I did notice that the two coils inside the basket weave coil are really a magnetic compass equivalent. This lead me to study the 1920-1930 Magnetic Compass to see how they worked. This then lead to the fact that IMHO the schematic is backwards and works from the left to the right using the theory of magnetic amplifiers, so I have been studying Magnetic Amplifiers from the 30's and 40's. Too many unknown components that all work together but I am a sucker for dream technology.

The adventure continues.

Great to hear that!
I'd like to see some better & closer pics from what you have built, and if you can include what specs you have used for each coil that would be awesome.

I was planning to start directly with the MKIII but thinking about all the devices I now am also inclined to first build the MKI and then progress, just like Hendershot did.

Although my knowledge is a bit rusty I'm an electronic engineer who studied also some radio engineering many years ago, I still have some real passion left for electronics and radio techniques. Besides that I'm a patient guy.

Awesome discovery about the magnetic compass, this would fit in extremely well since it was Hendershot's first goal after all - design a reliable compass that points to the real North (and work better than the induction compass). I'd have to pick up the specific knowledge also. If you have some good pointers to start that would be great.

[Allen Burgess]

Core neutral zone field reversal.

Core neutral zone field reversal works only up until the iron core reaches magnetic saturation, which doesn't take long. After that time the core has it's own field and no longer responds to the neutral zone shift. This may account for the very brief running time of the Hendershot motor!

[mikec_ut]

Limited time but still working on it

Hi Mike, I have been reading up on this thread and saw that this was your last post; has there been any progress? I hope you didn't give up as your set up showed you were on the eve of some very interesting experiences...!

@pjotterkjen
I have not given up yet. I didn't expect it to work on the first try but I wanted to get an idea of what it would look like. I did notice that the two coils inside the basket weave coil are really a magnetic compass equivalent. This lead me to study the 1920-1930 Magnetic Compass to see how they worked. This then lead to the fact that IMHO the schematic is backwards and works from the left to the right using the theory of magnetic amplifiers, so I have been studying Magnetic Amplifiers from the 30's and 40's. Too many unknown components that all work together but I am a sucker for dream technology.

The adventure continues.

[Cadman]

Comment removed. Sorry, it was a bad idea

[pjotterkjen]

I have already mathematically established that Lester's noted 7,800pF capacitance relates to a foil overwind over cartridge paper thickness wrapped around the orignal coffee can cores he originally used !

Cheers ............ Graham.

I think that value is not a magic one. According to Arthur Aho (who spend two and a half year testing the device together with Hendershot himself) that specific value of 7,8 pF was NOT that important but yes (and this makes real sense to me) the two caps should closely match (taken from Aho's 1968 notes):

"Fitting closely to the inner circumference of this triple coil was a condenser which was rewound from an 80 mfd, 400 volt electrolytic condenser, but dried before winding on a metal ring. The final capacitance was not critical. Units operated anywhere from 0.006 mfd to 40 mfd, but they were critical as to balance. Each side had to be within less than 2% in value to the other."

[pjotterkjen]

The adventure continues.

Hi Mike, I have been reading up on this thread and saw that this was your last post; has there been any progress? I hope you didn't give up as your set up showed you were on the eve of some very interesting experiences...!

[thx1138]

Magney Info

Can you share information on the magnet shown in post #173? Where you obtained it, overall size, space between poles, pole sizes, etc?

I'm putting together a parts list and am having trouble locating a suitable magnet. I can put together 10 pieces of neo magnets to make one but it's roughly $350 just for the pieces. That's more than half of the parts cost and I would like to get that cost down.

I did find some cloth covered wire that is 0.105" so that might have to do. The O.D. is not specified at the site but I left a message and they replied back with 0.105" O.D.
20 awg Solid Core, Cloth

[thx1138]

20 AWG insulated solid copper in L1 and L2

I got more info back from Belden wire from their 1941 catalog. They had a 20 AWG that had rubber insulation over a paper wrap and covered with a glazed cotton braid lacquered. The approximate O.D. was 0.100". I'm guessing either the cotton or the lacquer was colored to give the wire the red and yellow colors noted.

Today's PCV covered 20 AWG solid copper has an O.D. of 0.066". That gives us a difference 0.816" over 24 turns (12 each for L1 and L2) X .034". So that part is no longer a mystery. Just need to determine a way to make today's wire 0.100" O.D. The wire I linked to earlier was 0.120" to 0.125" so I'll keep looking.

[thx1138]

Epoxies with steel filings

Just an FYI the use of epoxies with steel filing such as liquid steel will effect the magnet's field strength. A clear epoxy usually works the best.

I'm glad you thought of it. I wouldn't have. Thanks.

[GSM]

According to designs published it were the two short alu strips that were wrapped first over the thick paper layer, together with the thin paper and then the long alu strip.

(just making counternotes as I'm reading up on the thread to the end; if it was already spotted then I apologize)

Onwards!

Published by whom ?????

I have already mathematically established that Lester's noted 7,800pF capacitance relates to a foil overwind over cartridge paper thickness wrapped around the orignal coffee can cores he originally used !

I have also very clearly shown a photograph of a coil wire on a Hendershot generator going to one of the can cores = 7,800pF no matter how many foil turns were wound on.
Also I have already posted in this thread old words relating to a *single* aluminium capacitor winding over the tin core.

Only two core-cap connections were used by Hendershot in his original generators, these connected to the outermost lower tuning winding likely related to the *longitudinal resonance frequency* of the tin can cores he originally used !

All of the different aluminium capacitor instructions must be suspected as being deliberately diversionary.

Cheers ............ Graham.