Sympathetic oscillation?

[Noel Branson]

I wouldn't have thought it possible!
I recently found and repaired another Schatz BA battery-wound torsion clock and set it next to the other example that I've had for a couple of years. They have identical movements but differ in style and have completely different pendulums. The older one is a typical Schatz 3-ball type, the newer one is a JUM-7 type.
I set them up and started them together, with opposite rotations, and six days later, they are still in perfect sync, i.e. they start and end rotations simultaneously! And have done so all week! They both keep excellent time.
I realise that to get one torsion clock to keep such good time is an achievement in itself, but two similar clocks, stood next to each other, in time and in sync, I wouldn't have believed possible. Could this be an example of sympathetic oscillation? I'd be fascinated to hear the views of the experts on this forum. What do you think, guys?

 

[etmb61]

Just a happy accident I'd say.

 

[Reconnaissanceman]

Keep us updated on the oscillations. If not sympathetic, it will break sync eventually.

 

[Wimberleytech]

Yeah, I am astounded by the accuracy myself. I serviced a couple of mine last year and they are not doing so great.
The term "sympathetic oscillation" was new to me. I have always called that phenomenon "injection locking" and have seen it on a few occasions on integrated circuits where one oscillator "pulls" another. Looked it up and, indeed, "sympathetic oscillation" is a form of injection locking.
In order to get injection locking, there must be a means for coupling. In your case, it is not air. It must be via the platform.
Keep us posted on the long-term observations.

 

[Noel Branson]

Yeah, I am astounded by the accuracy myself. I serviced a couple of mine last year and they are not doing so great.
The term "sympathetic oscillation" was new to me. I have always called that phenomenon "injection locking" and have seen it on a few occasions on integrated circuits where one oscillator "pulls" another. Looked it up and, indeed, "sympathetic oscillation" is a form of injection locking.
In order to get injection locking, there must be a means for coupling. In your case, it is not air. It must be via the platform.
Keep us posted on the long-term observations.

Yeah, I am astounded by the accuracy myself. I serviced a couple of mine last year and they are not doing so great.
The term "sympathetic oscillation" was new to me. I have always called that phenomenon "injection locking" and have seen it on a few occasions on integrated circuits where one oscillator "pulls" another. Looked it up and, indeed, "sympathetic oscillation" is a form of injection locking.
In order to get injection locking, there must be a means for coupling. In your case, it is not air. It must be via the platform.
Keep us posted on the long-term observations.

Well, another week has passed, and I'm happy to report that the clocks are still in sync and still keeping excellent time. It's amazing! I had intended to repaint the base of the floral one but I'm loth to disturb them. Think I'll leave them alone awhile longer and observe. I've been trying to work out how they're linked and I just can't see it. They sit on top of a cast iron room heater, a very stable platform, and that's their only connection. It's hard to see how momentum can pass between them, as I think it must. Somehow! Either that or some sort of black magic.
Anyway, I'll leave them alone for another few days and keep an eye on them. I have to say that I'm hugely gratified that the older one is finally fixed, as it's been a real pain since I got it, and it's good to have two different examples of what is a rare and interesting movement.