Rotor Mass !!

[JJ Irani]

Okay, guys....serious thread!!

Do watch manufacturers pay much importance to the mass of the rotor in determining how that mass affects the performance of the watch?

For example, how is the mass distributed?
Does a heavier rotor bring about a better performance and power reserve from the watch?

Anyone can throw more light on this subject?

Thanks - JJ

[padi56]

Relatively speaking,the rotor must be fairly heavy to be affected by gravity as you move your arms.In your case JJ quite quickly to keep your watch fully wound.But the most important is how efficient the rotor turning this mass, into energy, though the gear trains,to keep the main spring wound.Think of how a gear box on a car works, to transmit power though the drive train to the wheels.

[JJ Irani]

Originally Posted by padi56

Relatively speaking,the rotor must be fairly heavy to be affected by gravity as you move your arms.In your case JJ quite quickly to keep your watch fully wound.But the most important is how efficient the rotor turning this mass, into energy, though the gear trains,to keep the main spring wound.Think of how a gear box on a car works, to transmit power though the drive train to the wheels.

Thanks, Padi. Tell me, would a watch with a higher Power Reserve be fitted with a heavier rotor?

[padi56]

Originally Posted by JJ Irani

Thanks, Padi. Tell me, would a watch with a higher Power Reserve be fitted with a heavier rotor?

JJ its nothing to do with size or weight,but its got to be a certain weight before gravity comes into force.Its all down to the gearing,how the energy is transmitted from rotor/mass/energy/gears/clutch/main spring.Power reserve is all down to size of spring and how
much energy it can store.

[Gedanken]

Dunno about that, Peter. This goes back to the zero-gravity thread. It's not so much a matter of the weight of the rotor (affected by gravity), but instead its mass, which determines the rotor's inertia regardless of the plane in which the force acts. The ration of the rotor's inertia to the spring's resistance would be the key equation IMHO.

[Earl]

:o) damn someone brought up one of my old threads!!! "This goes back to the zero-gravity thread."

[Gedanken]

"Someone"? "SOMEONE"?!!!! What am I, chopped liver?!

[Rockrolex]

Originally Posted by Gedanken

"Someone"? "SOMEONE"?!!!! What am I, chopped liver?!

And what's wrong with chopped liver?

Here's an interesting tidbit. On the women's Rolex watches, the rotor they use doesn't have enough mass to fully wind the mainspring, such that if you wore it long enough to theoretically give it a full wind and then let the PR run down, it will 'die' many hours before what it is spec'ed to have as a PR.

You'd think Rolex would address this with a more dense metal for the rotor (like lead, platinum) but they don't.

[Gedanken]

Originally Posted by Rockrolex

And what's wrong with chopped liver?

Nothing, unless you happen to be donor of said liver.

[Rockrolex]

Originally Posted by Gedanken

Nothing, unless you happen to be donor of said liver.

Did you hear the chicken complain? I didn't hear the chicken complain.

Originally Posted by JJ Irani

Thanks, Padi. Tell me, would a watch with a higher Power Reserve be fitted with a heavier rotor?

On the subject of mass distribution, many rotors are fitted with a gold weight on the outer edge to skew the mass as far from the center of the rotor as possible. This provides more efficiency in the winding action. Here is an example in my JLC Master Moon:



Note the 22C rotor weight.

There are differences in efficiency depending on how the winding is configured - bidirectional winding or single direction. Where one system only winds in one direction, for a given movement of the rotor you get more winding of the main spring since energy is not lost while changing the gearing to wind in the other direction. It is largely accepted that most bi-directional systems are more efficient, although some less so than others. The key point here is that you don't get "2 times" the winding because it winds in both directions.

The power reserve is another issue altogether. The power reserve can be extended by a single larger spring, or by more than one barrel. In either case, some efficiency might be lost because the single spring is wound to a higher tension, or there must be a mechanism to wind the second barrel after the first is fully wound.

Disclaimer - I have only recently started looking into this area of watch technology so my answers are subject to correction. It is certainly something I am interested in knowing more about.

[Gedanken]

Originally Posted by Rockrolex

Did you hear the chicken complain? I didn't hear the chicken complain.

By that point in time, the chicken's just too damn gutless.

[Launch Mini]

Did you read last months Watchtime?
Had some interesting articles from various watchmakers about bidirectional or unidirectional auto winding also.

Originally Posted by Launch Mini

Did you read last months Watchtime?
Had some interesting articles from various watchmakers about bidirectional or unidirectional auto winding also.

Thanks for the heads up! I have the issue but haven't read it yet......getting behind on my reading lately.

[frank bullit]

Originally Posted by Gedanken

Dunno about that, Peter. This goes back to the zero-gravity thread. It's not so much a matter of the weight of the rotor (affected by gravity), but instead its mass, which determines the rotor's inertia regardless of the plane in which the force acts. The ration of the rotor's inertia to the spring's resistance would be the key equation IMHO.

I missed the zero gravity thread.
How DID the Omega(s) get on in 'space'.
Anybody know?

FB.

[padi56]

Originally Posted by frank bullit

I missed the zero gravity thread.
How DID the Omega(s) get on in 'space'.
Anybody know?

FB.

Check out these two threads.
Omega moon watch
http://www.rolexforums.com/showthrea...ht=omerga+moon

Zero gravity.

http://www.rolexforums.com/showthrea...hlight=gravity

[Earl]

hmmmm go figure a gutless chicken.. ;o) and to loose it's liver to the chopper.... damn.....

[Rockrolex]

Originally Posted by Earl

hmmmm go figure a gutless chicken.. ;o) and to loose it's liver to the chopper.... damn.....

You should have seen it when it was running around with its head chopped off.

[Russel]

Originally Posted by frank bullit

I missed the zero gravity thread.
How DID the Omega(s) get on in 'space'.
Anybody know?

FB.

The Omega watches used by the Apollo program were hand wind. Ironically, an automatic will work just fine in zero gravity as long as you wear it.

P.S. Why did the chicken cross the road? ..Hey! Now you guys have me doing the chicken thing too!!?

[Goodwatch]

To get to the other side I presume?

[padi56]

Originally Posted by Goodwatch

To get to the other side I presume?

Or as said by Neil Armstrong:
One small step for a chicken, one giant leap for poultrykind.

[frank bullit]

Originally Posted by padi56

Or as said by Neil Armstrong:
One small step for a chicken, one giant leap for poultrykind.

That's so bad!!!

I'm a vegetarian, yes, I only eat animals that eat grass!

Thank you, Ladies and Gentlemen, I'm here all week, be kind to your
waitress, and hey, try the chopped liver!

Frank.

[Goodwatch]

Originally Posted by padi56

Or as said by Neil Armstrong:
One small step for a chicken, one giant leap for poultrykind.

A bit meager I think (Like chicken breast )

[JJ Irani]

Guys,

Thanks for the intelligent (Al, Padi)) and the usual crazy hijacking remarks!! I noticed Ed time and again making repeated attempts at hijacking this thread, but each time someone did bring it back on track!!

Johnny, valid point about the ladies watches. Zemina's previous TT DJ did have this problem. She had to ensure she wore it at least 8 hours a day. If she didn't wear it for a day and a half it would stop.

However, with the 2235 movement in the Lady YM, she has no problems at all. This movement is rated with a PR of a whopping 50 hours and it just keeps going on and on.

Cheers all - JJ

[Gedanken]

Oh, that bloody tears it! I make the distinction between mass and weight and point out the role of inertia, and Al and Peter get the kudos? JJ, you're itching for an infraction here - that constitutes an insult!

By the way, the duck stayed on his own side of the road just to prove he was no chicken.