Fedchenko isochronous suspension

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Martin Kyte on 21/02/2023 10:54:24:

[…]

Regards Martin

PS My bits in bold

Edited By Martin Kyte on 21/02/2023 10:55:47

.

I really don’t have the will to debate this Martin … So let’s just say that perhaps my own statement was imprecise, because I only emboldened the one word [which was sloppy of me, but I was trying to be succinct].

I should really have emboldened the two words confirm and cannot, which [taken together] comprise what I consider scientifically unacceptable.

MichaelG.

[Michael GilliganParticipant @michaelgilligan61133]

Not sure if this will be of any use to anyone here, but I thought we should have it available:

**LINK**

https://download1979.mediafire.com/b7hocr106iugqq6MRH6r-_DCxKOHschZE48ZF8RaIPaNxNUWIp0GK9Kal3A0yq9oGAasAfJ5Ie4PQoNKyTL55FvTwSlMvAs/2w6ss6ogn90872k/File1.pdf

Some Fedchenko stuff, in Russian [or maybe Ukrainian]

MichaelG.
 

.

Russian Translation:

Rice. 40. Scheme of electromechanical precision pendulums
clock L. Galma
–
To = 2 sec, suspended on knife supports. He has a very high
goodness.
The release signal is formed during the left semi-oscillation of the pendulum 3,
when the flag-screen 1 fixed on its rod 2 comes out of the gap between the illumination
titel l and phototransistor FT. A pulse will appear at the output of the phototransistor
current, which, after amplification in the switching cascade assembled on the trans-
zistor P1, is fed into the electromagnet 4 of the drive system, completely similar
clock drive system EPCM and clock factory ECHL series P.

_________________

Ukrainian Translation:

Fig. 40. Scheme of electronic mechanical precision pendulums
of the times of L. Halm
–
To = 2 sec, suspended on knife supports. He has a very high
brotherhood
The release signal is formed during the left half-oscillation of pendulum 3,
when the flag-screen 1 fixed on its rod 2 comes out of the gap between the
with the title L and phototransistor FT. A pulse will appear at the output of the phototransistor
current, which after amplification in the switching cascade assembled on the transformer
voltage P1 is supplied to electromagnet 4 of the drive system, which is completely analogous
to the drive system of the EPCHM clocks and the ECHL factory clocks of the P series.

Edited By Michael Gilligan on 21/02/2023 18:58:11

[david bennett 8Participant @davidbennett8]

Posted by John Haine on 21/02/2023 09:44:50:

It's not as if people haven't investigated this before – I mentioned Kenneth James before, and Philip Woodward. Fedchenko points out that the restoring force from a straight spring has the wrong power law, being linear with deflection angle whereas the required force needs to have a cube law term. A double space is more likely to be a publication artefact bearing in mind that the paper dates from 1957 and could well be a translation from Russian.

Now I'm wondering if I should try to make a Fedchenko suspension?

John, I can see that more restoring power is needed than a straight spring can deliver, but surely the power for the long spring distortion is taken from the pendulum then given back to it, so no power gain. (we know it works, but I'm still missing something)

Dave8

[david bennett 8Participant @davidbennett8]

ps.

John, I think making a Fedchenko suspension would b e a great idea. It doesn't seem to have been done before, which seems strange. Most innovations are rapidly reproduced.

dave8

[John HaineParticipant @johnhaine32865]

I think it was ignored for several reasons. First it appeared in the 1950s by which time the world of standard time had already switched to quartz and the first atomic clocks were appearing. Second, like Harrison's circular cheeks, there isn't a satisfactory theory telling us how to design it, it seems to be necessary to "set on test" which is tedious and long-winded. Third, isochronism isn't necessarily a good thing (as Clock B shows), and anyway it is very easy to stabilise pendulum amplitude to render it irrelevant. On reflection, I don't think I'll be making one!

[david bennett 8Participant @davidbennett8]

John, thanks for your insights.

dave8

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