Automatic winding vs. manual wind, watch behaves completely different! - Page 2

# Thread: Automatic winding vs. manual wind, watch behaves completely different!

1. ## Re: Automatic winding vs. manual wind, watch behaves completely different!

Originally Posted by B24-1
Your sekaro use a seagull st16 movement, which only has 36 hours power reserve (factory's specification) and 42h reality (i can even run over 42h but very slowly). So dont supprise about 2 days without winding watch not run accuracy, because its power run out
By the way, watch with full-wound will run faster when it half-empty in same conditions, sure. You can check it with a timegrapher
Ps:my english is too bad, its hard to write a long comment, so dont mind if i have any mistake, thank you
Sure the best way to measure is using the time grapher. I only have the amateur-ish phone app version, and haven't use it for a long time. I might try it again.

The fact, power reserve is affecting the watch speed. And we know gravity is creating drag, and slowing the movement in certain angle. I wonder how movement regulator works? Should it be limiting the movement speed when it run too fast?

2. ## Re: Automatic winding vs. manual wind, watch behaves completely different!

When the mainspring is mostly wound down, it imparts less energy to be transmitted through the pallet-lever to the balance wheel. This may cause the balance wheel to swing in a smaller arc and therefore take less time per beat. This means that the watch will run fast. If the mainspring was to be imparting too much energy when fully wound, the result would be for the balance wheel to swing to its furthest limit and therefore take more time per beat i.e. run slow.

The theoretical timekeeping advantage of an automatic over a hand-winder is due to the mainspring remaining mostly wound most of the time (i.e. less torque variation). For this benefit to be realised, the mainspring needs to be long enough that the amount by which it winds down overnight is not enough to greatly vary the torque.

However there are many other variables that affect timekeeping.

3. ## Re: Automatic winding vs. manual wind, watch behaves completely different!

Originally Posted by Chascomm
When the mainspring is mostly wound down, it imparts less energy to be transmitted through the pallet-lever to the balance wheel. This may cause the balance wheel to swing in a smaller arc and therefore take less time per beat. This means that the watch will run fast. If the mainspring was to be too much energy when fully wound, the result would be for the balance wheel to swing to its furthest limit and therefore take more time per beat i.e. run slow.

The theoretical timekeeping advantage of an automatic over a hand-winder is due to the mainspring remaining mostly wound most of the time (i.e. less torque variation). For this benefit to be realised, the mainspring needs to be long enough that the amount by which it winds down overnight is not enough to greatly vary the torque.

However there are many other variables that affect timekeeping.
One thing you forgot, the less power, the slower balance wheel swing
You can check it with a zero power watch, wound it 4-5 turn and watch it run
Very very slowly

4. ## Re: Automatic winding vs. manual wind, watch behaves completely different!

No, the balance always swings at the same speed, so if there is less energy pushing it then it will swing in a smaller arc and the watch will run faster. If your watch runs very slowly on low power, then the cause with likely be excess friction in some other part of the movement.

5. ## Re: Automatic winding vs. manual wind, watch behaves completely different!

Originally Posted by Chascomm
No, the balance always swings at the same speed, so if there is less energy pushing it then it will swing in a smaller arc and the watch will run faster. If your watch runs very slowly on low power, then the cause with likely be excess friction in some other part of the movement.
You can check it by yourself, when power is mostly down, the balance wheel will swing very slow
Should i make a clip for you?
Btw, this is the first time i hearing someone say watch run faster when power slower, everyone else only have loss time problem when watch's power nearly empty

6. ## Re: Automatic winding vs. manual wind, watch behaves completely different!

Originally Posted by B24-1
You can check it by yourself, when power is mostly down, the balance wheel will swing very slow
Should i make a clip for you?
That's OK, I've got plenty of watches I can look at.

When there is less power to move the balance, it will not swing as far. Look closely at your almost unwound movement. You see the balance swinging weakly, but is it swinging as far as when it is swinging strongly?

To look at it from another perspective; you know those desktop toys with the steel balls on string? As the swinging balls lose energy, you will hear the interval between each click gets less each time.

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