Do you need a rotor to make a Valjoux 7750 run ?
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  1. #1
    stuffler,mike
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    Do you need a rotor to make a Valjoux 7750 run ?

    Probably not:



    This is a prototype of a "ball-bearing" based 7750 which IŽve seen on my Damasko vistit on Saturday. A complete report will be finished next weekend and published on out German Watches Forum. YouŽll already find some more explanation there.

  2. #2
    Member Gordon's Avatar
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    Re: Do you need a rotor to make a Valjoux 7750 run ?

    Interesting! Rotor vs Ball bearings..... Anyone care to discuss the
    pros and cons.....

  3. #3
    Administrator Ernie Romers's Avatar
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    Re: Do you need a rotor to make a Valjoux 7750 run ?

    Well, putting the inventive innovation aside, I'd like to know the reason for the research. In other words, why would a ball bearing system be better than the rotor we all know? I'm not an expert when it comes to technical apsects but this question did cross my mind.
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    Ernie Romers
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  5. #4
    Member cnmark's Avatar
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    Re: Do you need a rotor to make a Valjoux 7750 run ?

    Looks a little like the rejuvenation of the "bumper" - does it?

  6. #5
    Member KenC's Avatar
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    Re: Do you need a rotor to make a Valjoux 7750 run ?

    Quote Originally Posted by WatchUseek Admin View Post
    Well, putting the inventive innovation aside, I'd like to know the reason for the research. In other words, why would a ball bearing system be better than the rotor we all know? I'm not an expert when it comes to technical apsects but this question did cross my mind.
    Ernie, just from the looks of it, the advantage, imo, would be fewer moving parts a no "wearing" surfaces! But I would hate to lose the thrill of the "wobble"!
    "Find the little bastards......and then pile on!" Maj Gen George S Patton IV



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  7. #6
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    Re: Do you need a rotor to make a Valjoux 7750 run ?

    Very interesting. What are the advantages of using the ball bearing system over the rotor system apart from the fact that rotor needs bearings that required to withstand higher centrifugal forces?

    I love the wobble too, if they increase the bearing race travel to 180 degrees, I think the wobble would be maintained?


  8. #7
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    Re: Do you need a rotor to make a Valjoux 7750 run ?

    I would think the cons would be, added weight & increased noise.
    Greetings from that Island they call Long!

  9. #8
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    Re: Do you need a rotor to make a Valjoux 7750 run ?

    Quote Originally Posted by Gordon View Post
    Interesting! Rotor vs Ball bearings..... Anyone care to discuss the
    pros and cons.....
    Difficult to see how the pros and cons would balance out. All the offset loads on the center bearing are in a narrow arc instead of distributed round the 360 ddegrees, but te loads are much smaller because the balls are constrained by the case. The winding arc is much shorter than with a conventional rotor, though I don't see why it needs to be as short as the example's. I think the friction between the balls and the case would result in more losses than the offset bearing loads from a rotor.
    I don't think the comparison is susceptible to a qualitative analysis. You'd either have to attack it with mathematics or carry out physical tests.

  10. #9
    Member obsidian's Avatar
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    Re: Do you need a rotor to make a Valjoux 7750 run ?

    Well, the movement would be wider, because of the bearing track-- but since I've seen 7750's inside 36mm cases, the current 40mm plus trend in chronograph cases should provide plenty of room-- and would provide a nicer view through a view back, since the movement would fill bigger cases better. . As the bearings add to the width of the case, the removal of the rotor will allow for thinner cases-- and let's face it, the 7750 is an overly thick movement.
    The best watch is the one that makes you happiest... and tells the time.

  11. #10
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    Re: Do you need a rotor to make a Valjoux 7750 run ?

    I doubt the added weight , im shure they would use ceramic ball bearings, but it would be noisy as hell , like a can of spray paint if one got loose !


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