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Discussion Starter · #1 ·
Disclaimer first: I have no knowledge of electrical engineering, but this is just my naive thoughts.

A lot of discussions are centered on how Spring Drive can generate enough power for the IC, especially in the thermocompensated 9RA2/5. However, that got me thinking: there must be more power generated than the IC and braking mechanism require, however small. Where does it go?

Or is it more subtle than this? And if so, how?
 

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Disclaimer first: I have no knowledge of electrical engineering, but this is just my naive thoughts.

A lot of discussions are centered on how Spring Drive can generate enough power for the IC, especially in the thermocompensated 9RA2/5. However, that got me thinking: there must be more power generated than the IC and braking mechanism require, however small. Where does it go?

Or is it more subtle than this? And if so, how?
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;)
 

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Also bear in mind that the Spring Drive generator only makes about 25 nano Watts of electricity. That's 0.000000025 of a Watt. If my rough math is correct that means that if you took every Spring Drive watch ever made, and wired them all together, all running at once, you still would only have about 1 hundredth of a Watt of power.
 

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Generally getting rid of small amounts of electrical energy is pretty easy, as was already pointed out just use a resistor. But I suspect Seiko had some electrical engineers help with the design that figure out how much energy was needed, so there isn't a lot of extra energy to heat your wrist.
 

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Also bear in mind that the Spring Drive generator only makes about 25 nano Watts of electricity. That's 0.000000025 of a Watt. If my rough math is correct that means that if you took every Spring Drive watch ever made, and wired them all together, all running at once, you still would only have about 1 hundredth of a Watt of power.
Where did 25 nano-watt come from ?
I found this from Eiichi Hiraya
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Assuming a 1volt supply gives a 45 nano watts power-requirement for the IC
Assuming 100% safety-factor for the speed-control system gives a total generation of 90 nano-watts.
-- Still tiny. A Renata 371 battery can supply about 1.5 micro-watt for 4.5 years
 

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Where did 25 nano-watt come from ?
Joe Kirk has mentioned the number rather often in his presentations, and elsewhere.

Grand Seiko Black Ceramic Limited Editions - SBGC015...
"This device, called the Tri-Synchro Regulator, converts the mechanical energy from the mainspring (once passed through the gear train) into a tiny amount of electricity (25 nano watts)."

The number is oft-repeated in media referencing Seiko/Spring Drive, though some reference 25 nanowatts of power generated, and some reference 25 nanowatts of power consumed.

Grand Seiko Spring Drive 9R 10th Anniversary SBGA109 Plus Grand Seiko Roadshow | aBlogtoWatch
"When this wheel turns, a small amount of electricity (25 nanowatts) to power an IC and quartz crystal."

Grand Seiko’s Master Watchmaker: Interview With Yoshifusa Nakazawa | aBlogtoWatch
"They helped to produce an extremely low power consumption IC. It consumed only 25 nanowatts; 100 times less than the first prototype."

https://www.watchonista.com/article...seiko-our-unbelievable-visit-brands-workshops
"Basically, this quartz oscillator uses the energy of the mainspring to [generate] small bursts of energy (approx 25 nanowatts) to drive the watch."

http://www.ecpe.nu.ac.th/suchart/SPEC/SPEC022009.PDF
"Development continued for another eight years, during which the watch’s power consumption was reduced still more, to just 25 nanowatts."

https://www.ft.com/content/e9dcf891-f600-4d77-8cba-ca0961de98e7
"As the watch unwinds it powers a rotor that produces enough electricity (a meagre 25 nanowatts) to cause the quartz crystal to give out a reference signal to an integrated circuit Seiko calls a Tri-synchro regulator."

https://en.wikipedia.org/wiki/Seiko
"The Tri-synchro regulator has three main functions: controlling the mechanical energy of the mainspring, generate electricity for the low consumption (~25 nanowatts) quartz crystal oscillator and generate a magnetic force to regulate the glide wheel."

https://www.newworldencyclopedia.org/entry/Seiko
"Energy produced by the glide wheel powers a control circuit and a tiny, ultra-low consumption (~25 nanoWatts) quartz crystal oscillator, which in turn regulates the electro-mechanical braking of the glide wheel."
 

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Joe Kirk has mentioned the number rather often in his presentations, and elsewhere.
Thanks, that is very interesting.
The quotes are a bit unclear about some detail, but this is my interpretation :-
- The electronics uses 45nano-amp, 25nano-watt
It must work at about 0.5volt -- a low voltage for year-2000 technology.

But the generator must also absorb braking-power
As a minimum this needs to be the difference between 'fully wound, new' and 'unwound, needs a service' conditions.
So I think that the maximum generator output will be at least 50 nano-watt

A Renata 371 battery can supply about 2500 nano-watt for 2.5 years


The IWC caliber 59210 ( 7 day manual-wind) mainspring can
- store 1500 milli-joules
- deliver an average of 2500 nano-watt for 1 week
It might deliver
  • 3000 nano-watt when fully wound
  • 2000 nano-watt 'just before the watch stops'
If used for a Spring Drive :-
With transmission efficiency of 50% the generator must absorb up to 500 nano-watt.
With generator efficiency of 50% the maximum 'brake' output would be 250 nano-watt
The maximum generator output would be 275 nano watt.

I believe that the Seiko spent a lot of time developing SpringDrive springs.
Perhaps the SD-springs store less energy than the IWC-springs, but deliver it in a very uniform way.

A lot of speculation, but ( certainly for me) it helps to appreciate the Spring Drive technical achievement !
 

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Spring Drive uses insanely low power. Trivial to incorporate a tiny Resistor which will convert the power to heat, at those power levels it's essentially imperceptible. I just tried to find a really neat YouTube video I watched about the Spring Drive that goes into very deep details and answers all sorts of questions like this but I can't find it for some reason. Basically every spring drive ever created added up equal a tiny total. If I find it again I'll send it.
 

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Discussion Starter · #12 ·
Spring Drive uses insanely low power. Trivial to incorporate a tiny Resistor which will convert the power to heat, at those power levels it's essentially imperceptible. I just tried to find a really neat YouTube video I watched about the Spring Drive that goes into very deep details and answers all sorts of questions like this but I can't find it for some reason. Basically every spring drive ever created added up equal a tiny total. If I find it again I'll send it.
I don't suppose it was this one?

I haven't really seen anyone talk about how excess power is dissipated, but I guess it's a trivial matter for anyone that knows something about circuits (which I clearly don't). I have seen the 25nW number often and how it uses very little power.

It's also interesting to me that there's not as much appreciation for the miniaturization of the IC amongst Spring Drive detractors in relation to mechanical. I suppose in a mechanical you can physically see the intricate gears and everything, whereas you see a chip in a watch and think, well someone just slapped any old "computer" in there and we're good to go .
 

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Spring Drive uses insanely low power. Trivial to incorporate a tiny Resistor which will convert the power to heat, at those power levels it's essentially imperceptible. I just tried to find a really neat YouTube video I watched about the Spring Drive that goes into very deep details and answers all sorts of questions like this but I can't find it for some reason. Basically every spring drive ever created added up equal a tiny total. If I find it again I'll send it.
I found the attached presentation in the HAQ forum thread
High Beats vs Spring Drive vs Tuning Fork vs Electrical Clock


It gives a very good explanation of the operation of a Spring-Drive watch.
I did not know that Swatch invented Spring-Drive
- Grand Seiko just turned a brilliant concept into a commercial product !
 

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Oh......here we go again.......
🥱🥱🥱🥱🥱
I too am bored by 'who invented it first' arguments.
But the description attached to my post was the best that I have seen & I thought that other SD enthusiasts might like to read it !
 

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The topic has been covered...years ago!
Swatch invented s#it 😉
 

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Well, parallel invention happens all the time. Heck, I spent a bunch of time in airports recently and "invented" a collapsible cloth holder that you could put on the pull-up handle of your rolling suitcase to hold drinks and such. When I got home and checked Amazon I found out that that other people already invented it and they are readily available for purchase (I bought one). :)

The Swiss Asulab had an idea to do electromagnetic braking in a watch movement. I don't remember if Asulab has more than one patent, but this one is dated 1972. Interestingly that one appears to have also been filed in Japan but the patent never issued there. In any event Asulab was never able to turn it into a commercially viable product.

Seiko claims that Akahane came up with the idea in 1977 (5 years later). To my knowledge there is no evidence to suggest that Akahane was aware of Asulab's endeavor. Seiko merged with Epson corporation about 8 years later in 1985. I would speculate that having access to Epson's technological depth in electronics played no small role in Seiko's ability to resolve the power consumption and size issues that likely derailed Asulab's efforts.

Seiko had to develop completely in-house, ultra-low-current integrated circuits to get the power consumption down to something that could run on the minuscule current generated by the glide wheel. They even made their own wire with a hexagonal cross-section to allow the windings on the electricity-generating coils to be wound more densely and thus generate more current.

Imagine the frustration Akahane (and Asulab) must have felt, having this brilliant idea, but being unable to generate enough electricity to make it work in something the size of a wristwatch. Seiko solved the problem with their special coil winding (make more electricity) and custom IC's (require less electricity).

I hold two in-force U.S. patents with 2 new patents presently pending. I've been down the patent road several times now. There's no shame for Seiko if Asulab was chasing the same idea they were, even if Asulab started chasing it before Seiko did. Whatever Asulab protected with a patent would be off limits until that patent expired. Once the patent expired then that information would fall into the public domain, free to be used by anybody. Obviously Seiko had plenty of "novel" claims (things not in Asulab's "prior art") as they have a rather large number of patents on various aspects of the invention they call Spring Drive.

I found the Seiko and Asulab patents to be a fascinating read. When reading through them I can't help but wonder which aspects are and are not present in the commercial units that are sold today.

Eh, sorry this got long. I do that sometimes. :)
 
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Imagine the frustration Akahane (and Asulab) must have felt, having this brilliant idea, but being unable to generate enough electricity to make it work in something the size of a wristwatch. Seiko solved the problem with their special coil winding (make more electricity) and custom IC's (require less electricity).
s got long. I do that sometimes. :)
I do not think that you have read the presentation from Asulab that I attached to my first post.
It a very good presentation, it talks about
  • Why SD is a good idea
  • The details of how the HPM spring-drive worked
  • The tests carried out to check accuracy and reliability
It claims that they manufactured 150 movements and shows the results of 900-day accuracy and reliability tests.
It indicates that Asulab had solved the basic power problem ( they mention 45 hour autonomy ), but for reasons not discussed in the paper did not decide to proceed into series production.

As a technical nerd I am only interested in understanding the details of how SD watches work.
The Asulab paper is the best information that I have found.


But the HPM never went into series production. A detailed description of the Grand Seiko technology would be much better.
If anybody knows of such a paper can they post a link to it ?

Or can the people at GrandSeiko write a technical paper of similar detail to the Asulab paper ?
I cannot believe that divulging that amount of detail would damage their intellectual property
 

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I do not think that you have read the presentation from Asulab that I attached to my first post.
Do you mean the PDF attached to post #13? I have downloaded it but not read it. I'll check it out. Thanks!
 

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Discussion Starter · #20 ·
My god this sent me down the rabbit hole...😂😅

Regardless of who invented it first, it's interesting how on board Swatch was with this technology, whenever this paper was published (seems to be at least 1997 given it cites papers from 1997):

The self-winding mechanism and the mechanical energy storage in the main spring give the user a reliability and comfort which is significantly better than both, the traditional mechanical movement (because the most critical elements – resonator and escapement – have been replaced by more reliable and more precise ones) and the traditional electronic quartz movement (because its most unreliable element – the electrochemical power source – has been replaced by a system of constant availability and unlimited lifetime).
 
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