Date   

Re: Group Focus

James Kelly
 

Hi All

As the owner and moderator of the site I have no objections to posts about any make or model of electric clock, members of the original yahoo group will recall that there was always questions being asked about electro-mechanical clocks of all types.

Further take a quick look in the photos section and you will see files with clocks by makers other than Synchronome.

The stated aim of this group has always been as follows and this can be seen on the home page, 

Welcome to the Synchronome1 electric clock group. This group is run by enthusiasts and is concerned with issues relating to electric clocks: Precise, accurate, domestic and industrial. 

It just remains for you all to post and ask questions regarding any type of elctro-mechanical clock, be it technical or historical or restoration, adjustment, just post and ask away.

One final word, I hope everyone has managed to stay safe during the pandemic, and with the additional free time you may have enjoyed I hope you have been working on your clocks and enjoying them as you should

All the best

Jim Kelly
 


Re: Group Focus

Bepi
 

John, I approve your proposal of course, I am building an EM pulsed double pendulum right now, will they be included too in your change of focus? Even if they go back to Huygens and not Galileo like the others, double penduli will never have a forum on their own, right now it feels terribly lonely.
Thinking along those lines I was asking myself what would have been the dream forum given my interests and what you are proposing is very close but excludes the community of precision regulators. According to me the extraordinary new diagnostic opportunities offered by quartz clocked processors is what nowadays propels most of the interest, and developments, in precision EM, and mechanical, escapements. Wouldn't be wonderful to unite everybody interested in both these fields under the same ombrella given that the tools of the trade, both theory and practice, are the same? Another problem which interests me is the one of rejuvenating the pool and entering the word computer may help. I have noticed something similar happening with electronics/radio amateurs. 
p.-

On Dec 6, 2020, at 10:51, John Haine <john.haine@...> wrote:

I wonder if I could make a modest proposal for the focus of this group?  I joined about 2 years ago, moving across from the old Yahoo group, and over the past couple of years have found it very interesting and useful.  I see that the frequency of posting has fallen off a lot in recent months, I'm not sure why this is though there have been distracting things going on in real life! 

I have posted quite a lot about my own clock as I got it built and working - it's now reached the boring phase where it just sits on the wall and keeps time pretty well.  Meanwhile I've built another clock, not on 'Nome principles at all (though it is electromagnetic), and I'm just starting on a third inspired by the Fedchenko EM clock.

So should we broaden the focus of this group to include other EM (pendulum?) clocks, either being made or restored/collected?


--
Bepi


Re: Group Focus

Daniel Benson
 

I'm open to the idea of expanding the focus beyond Synchronome, but well defined within Em clocks.


Re: Group Focus

Ken Strauss
 

I almost never post here (I have little expert synchronome knowledge to offer) but I’ve learned a great deal and I am interested in all aspects of electromagnetic clocks. I heartily second John’s suggestion!

 

From: synchronome1@groups.io <synchronome1@groups.io> On Behalf Of John Haine
Sent: December 6, 2020 4:51 AM
To: synchronome1@groups.io
Subject: [synchronomeelectricclock] Group Focus

 

I wonder if I could make a modest proposal for the focus of this group?  I joined about 2 years ago, moving across from the old Yahoo group, and over the past couple of years have found it very interesting and useful.  I see that the frequency of posting has fallen off a lot in recent months, I'm not sure why this is though there have been distracting things going on in real life! 

I have posted quite a lot about my own clock as I got it built and working - it's now reached the boring phase where it just sits on the wall and keeps time pretty well.  Meanwhile I've built another clock, not on 'Nome principles at all (though it is electromagnetic), and I'm just starting on a third inspired by the Fedchenko EM clock.

So should we broaden the focus of this group to include other EM (pendulum?) clocks, either being made or restored/collected?


Re: Group Focus

Odell, Edward
 

There is also another group

electric-clocks@groups.io

covering other electromagnetic clocks, with members in common between the two

Eddy Odell

 

From: synchronome1@groups.io <synchronome1@groups.io> On Behalf Of jmfranke via groups.io
Sent: 06 December 2020 13:02
To: synchronome1@groups.io; John Haine <john.haine@...>
Subject: Re: [synchronomeelectricclock] Group Focus

 

I would very much like to see an expansion such as you suggest.

John Franke

On December 6, 2020 at 4:51 AM John Haine <john.haine@...> wrote:

I wonder if I could make a modest proposal for the focus of this group?  I joined about 2 years ago, moving across from the old Yahoo group, and over the past couple of years have found it very interesting and useful.  I see that the frequency of posting has fallen off a lot in recent months, I'm not sure why this is though there have been distracting things going on in real life! 

I have posted quite a lot about my own clock as I got it built and working - it's now reached the boring phase where it just sits on the wall and keeps time pretty well.  Meanwhile I've built another clock, not on 'Nome principles at all (though it is electromagnetic), and I'm just starting on a third inspired by the Fedchenko EM clock.

So should we broaden the focus of this group to include other EM (pendulum?) clocks, either being made or restored/collected?


 


Re: Group Focus

jmfranke
 

I would very much like to see an expansion such as you suggest.

John Franke

On December 6, 2020 at 4:51 AM John Haine <john.haine@...> wrote:

I wonder if I could make a modest proposal for the focus of this group?  I joined about 2 years ago, moving across from the old Yahoo group, and over the past couple of years have found it very interesting and useful.  I see that the frequency of posting has fallen off a lot in recent months, I'm not sure why this is though there have been distracting things going on in real life! 

I have posted quite a lot about my own clock as I got it built and working - it's now reached the boring phase where it just sits on the wall and keeps time pretty well.  Meanwhile I've built another clock, not on 'Nome principles at all (though it is electromagnetic), and I'm just starting on a third inspired by the Fedchenko EM clock.

So should we broaden the focus of this group to include other EM (pendulum?) clocks, either being made or restored/collected?


 


Group Focus

John Haine
 

I wonder if I could make a modest proposal for the focus of this group?  I joined about 2 years ago, moving across from the old Yahoo group, and over the past couple of years have found it very interesting and useful.  I see that the frequency of posting has fallen off a lot in recent months, I'm not sure why this is though there have been distracting things going on in real life! 

I have posted quite a lot about my own clock as I got it built and working - it's now reached the boring phase where it just sits on the wall and keeps time pretty well.  Meanwhile I've built another clock, not on 'Nome principles at all (though it is electromagnetic), and I'm just starting on a third inspired by the Fedchenko EM clock.

So should we broaden the focus of this group to include other EM (pendulum?) clocks, either being made or restored/collected?


Re: The Impulse Roller & Shape of Pallet

Bepi
 

Thanks Neville, absolutely brilliant, this is exactly what I was looking for, not too difficult at all to implement. It certainly wouldn't be a convenient way to put the clock "in beat". I'll think about how to execute it and hope to perform the experiment soon, p.-


On Nov 14, 2020, at 22:25, Neville Michie via groups.io <neville_michie@...> wrote:

If you were prepared to make a serious task out of the experiment,
you could add a horizontal bar with an adjustable weight, to displace the 
pendulum zero position. The escapement would stay the same, but the 
pendulum zero would shift. The major inconvenience is retuning 
the pendulum with the additional hardware. Se diagram.

cheers, Nevville

On 15 Nov 2020, at 06:53, Bepi <pepicima@...> wrote:

Neville, I don't understand: when one moves the pendulum sideways the drawing arm unlocks the gravity arm with a phase which changes with continuity, it's equivalent to lengthening or shortening the drawing arm. At the same time the gravity arm would hit the pallet profile at different locations though, changing effectively the shape and strength of the pulse. Moving the pendulum to the left, from one position on, the pulse doesn't even change its timing at all.
I am confused, is there a way to cleanly change just the phase? Rotating gravity by tilting the whole support plate around the roller axis?

p.-

The phase of the impulse can be adjusted by moving the pendulum sideways with the adjustment 
above the suspension.
I would be convinced 


On Nov 14, 2020, at 14:20, Neville Michie via groups.io <neville_michie@...> wrote:

The phase of the impulse can be adjusted by moving the pendulum sideways with the adjustment 
above the suspension. I seem to remember instructions for adjusting this so the roller was 
halfway down the slope when the pendulum was still and the latch tripped.
cheers, 
Neville Michie
On 14 Nov 2020, at 23:42, Bepi <pepicima@...> wrote:

Ian who are Mr Parsons and Mr Ball and where can I read about their results? I agree that the shape is probably of little importance, more relevant is the location of the impulse in phase/time.
Does anybody know how to regulate the impulse phase in a synchronome in an easy, controllable and accurate way?
The shape might be of some relevance in terms of repeatability which boils down to absence of sharp corners. 
-- 
Bepi










-- 
Bepi





<Pendulum Mod.jpg>


--
Bepi


Re: The Impulse Roller & Shape of Pallet

Neville Michie
 

If you were prepared to make a serious task out of the experiment,
you could add a horizontal bar with an adjustable weight, to displace the 
pendulum zero position. The escapement would stay the same, but the 
pendulum zero would shift. The major inconvenience is retuning 
the pendulum with the additional hardware. Se diagram.

cheers, Nevville

On 15 Nov 2020, at 06:53, Bepi <pepicima@...> wrote:

Neville, I don't understand: when one moves the pendulum sideways the drawing arm unlocks the gravity arm with a phase which changes with continuity, it's equivalent to lengthening or shortening the drawing arm. At the same time the gravity arm would hit the pallet profile at different locations though, changing effectively the shape and strength of the pulse. Moving the pendulum to the left, from one position on, the pulse doesn't even change its timing at all.
I am confused, is there a way to cleanly change just the phase? Rotating gravity by tilting the whole support plate around the roller axis?

p.-

The phase of the impulse can be adjusted by moving the pendulum sideways with the adjustment 
above the suspension.
I would be convinced 


On Nov 14, 2020, at 14:20, Neville Michie via groups.io <neville_michie@...> wrote:

The phase of the impulse can be adjusted by moving the pendulum sideways with the adjustment 
above the suspension. I seem to remember instructions for adjusting this so the roller was 
halfway down the slope when the pendulum was still and the latch tripped.
cheers, 
Neville Michie
On 14 Nov 2020, at 23:42, Bepi <pepicima@...> wrote:

Ian who are Mr Parsons and Mr Ball and where can I read about their results? I agree that the shape is probably of little importance, more relevant is the location of the impulse in phase/time.
Does anybody know how to regulate the impulse phase in a synchronome in an easy, controllable and accurate way?
The shape might be of some relevance in terms of repeatability which boils down to absence of sharp corners. 
-- 
Bepi










-- 
Bepi






Re: The Impulse Roller & Shape of Pallet

Bepi
 

Neville, I don't understand: when one moves the pendulum sideways the drawing arm unlocks the gravity arm with a phase which changes with continuity, it's equivalent to lengthening or shortening the drawing arm. At the same time the gravity arm would hit the pallet profile at different locations though, changing effectively the shape and strength of the pulse. Moving the pendulum to the left, from one position on, the pulse doesn't even change its timing at all.
I am confused, is there a way to cleanly change just the phase? Rotating gravity by tilting the whole support plate around the roller axis?

p.-

The phase of the impulse can be adjusted by moving the pendulum sideways with the adjustment
above the suspension.
I would be convinced


On Nov 14, 2020, at 14:20, Neville Michie via groups.io <neville_michie=yahoo.com@groups.io> wrote:

The phase of the impulse can be adjusted by moving the pendulum sideways with the adjustment
above the suspension. I seem to remember instructions for adjusting this so the roller was
halfway down the slope when the pendulum was still and the latch tripped.
cheers,
Neville Michie
On 14 Nov 2020, at 23:42, Bepi <pepicima@gmail.com> wrote:

Ian who are Mr Parsons and Mr Ball and where can I read about their results? I agree that the shape is probably of little importance, more relevant is the location of the impulse in phase/time.
Does anybody know how to regulate the impulse phase in a synchronome in an easy, controllable and accurate way?
The shape might be of some relevance in terms of repeatability which boils down to absence of sharp corners.
--
Bepi






--
Bepi


Re: The Impulse Roller & Shape of Pallet

Michael Gilligan
 
Edited

Thanks for the welcome and the additional information, John
... I signed-up here on your recommendation at Model Engineer 

I should perhaps just mention, for everyone’s benefit, that my plots relate specifically to the illustration and description in ‘Electric Clocks’ and are probably not directly relevant to later production.

MichaelG.
.

When describing the Synchronome system at the Institution of Electrical Engineers in February, 1910, I drew a force curve and showed how the end of the pallet J should be shaped to achieve this. In the discussion which followed that paper, Mr. W. H. Shortt, M.Inst. C.E., contributed a mathematical solution of its best form, which I give with the assistance of fig. 101.


Re: The Impulse Roller & Shape of Pallet

Odell, Edward
 

Hi Ian

 

Yes, that was done as a development before the Shortt in two types of clock, using the inertia bar principle.  In these the idea, as in the Shortt, is that the speed of pendulum movement lengthens or shortens the impulse duration to maintain constant amplitude.

 

This was first done in 1 second and ¾ second clocks but only 2 I know of survive.  Most unusually for Synchronome this mechanisms required a crutch and these clocks never made it into Synchronome brochures despite at least one having been sold to a customer.  See Bob miles book page 155.  I am very interested in this type if anyone knows of any more examples, I have one

 

The principle was then developed in the Shortt Observatory regulator

https://clockdoc.org/default.aspx?aid=11206

and nice paper in AHS journal March 2017

 

Eddy Odell

 

From: synchronome1@groups.io <synchronome1@groups.io> On Behalf Of Ian Richardson via groups.io
Sent: 14 November 2020 16:02
To: synchronome1@groups.io
Subject: Re: [synchronomeelectricclock] The Impulse Roller & Shape of Pallet

 

Hi All,

 

To add even further to the confusion, in Shortt's "free pendulum" clock, the impulse arrangement is the other way round!  The pallet (actually the flat surface of a Brocot jewel) rolls over and around the wheel.  It starts "dead" as a tangent to the wheel at the top, and falls down, rotating the wheel, until it drops off.  That has always seemed to me to be a better arrangement which could easily have been incorporated into an otherwise standard Synchronome.  Has anyone ever done that?

 

Ian R



-----Original Message-----
From: Bepi <pepicima@...>
To: synchronome1@groups.io
Sent: Sat, 14 Nov 2020 16:02
Subject: Re: [synchronomeelectricclock] The Impulse Roller & Shape of Pallet

Hal, to minimize the escapement error, in my synchronome it can be made undetectable, you need to carefully center the impulse around the phase corresponding to a vertical pendulum rod. Adding energy when it's all kinetic doesn't change the period in the small angle approximation.

This is why I was looking for a way to mechanically control the phase with precision. Thanks Neville about your answer, I am still looking for a way to do it with better accuracy than by hand, I guess I need to devise a simple process to do it.

I am not claiming it's a needed adjustment for best accuracy, the opposite, I think I reported long ago in this forum that minimizing the escapement error doesn't significantly affect the period in the short turn accuracy, even a large escapement error seems to be very repeatable in a synchronome.

 

 

 

On Nov 14, 2020, at 14:47, H Hal via groups.io <haal@...> wrote:

 

Don't worry Bepi,

I live in a constant state of confusion.

You are impulsing the pendulum at some point during its swing. There are some points (during the swing) that the impulse will be very useful and efficient OR other points where the impulse will be detrimental (the child pushed by dad on the swing gets higher and higher OR gets lower and lower to a stop because it is tea time).

The phase angle represents a point somewhere on that sine curve (which represents the position of the pendulum in time) where impulse may be given.

?

 

On 14/11/2020 13:11, Bepi wrote:

Hal, sorry for adding to the confusion, let me make it worse now. In my pseudo-synchronome I control the clock-cycle phase of the impulse by changing a time delay starting from the previous period vertical crossing but it's clearer to speak about a phase angle, as in the angle of the tangent rule, p.-



On Nov 14, 2020, at 13:46, H Hal via groups.io <haal@...> wrote:

 

hi Bepi,

 

can you explain the difference between phase and time in relation to impulse or are you using the terms interchangeably?

 

regards

 

hal

On 14/11/2020 12:42, Bepi wrote:

Ian who are Mr Parsons and Mr Ball and where can I read about their results? I agree that the shape is probably of little importance, more relevant is the location of the impulse in phase/time.
Does anybody know how to regulate the impulse phase in a synchronome in an easy, controllable and accurate way?
The shape might be of some relevance in terms of repeatability which boils down to absence of sharp corners. 
--
Bepi

--
Bepi


--
Bepi


Re: The Impulse Roller & Shape of Pallet

Ian Richardson
 

I should have added that the "pallet" (ie. Brocot jewel) is attached to the gravity arm and the wheel is attached (albeit loosely) to the pendulum rod.

Ian


-----Original Message-----
From: Ian Richardson via groups.io <irichar361@...>
To: synchronome1@groups.io <synchronome1@groups.io>
Sent: Sat, 14 Nov 2020 17:02
Subject: Re: [synchronomeelectricclock] The Impulse Roller & Shape of Pallet

Hi All,

To add even further to the confusion, in Shortt's "free pendulum" clock, the impulse arrangement is the other way round!  The pallet (actually the flat surface of a Brocot jewel) rolls over and around the wheel.  It starts "dead" as a tangent to the wheel at the top, and falls down, rotating the wheel, until it drops off.  That has always seemed to me to be a better arrangement which could easily have been incorporated into an otherwise standard Synchronome.  Has anyone ever done that?

Ian R



-----Original Message-----
From: Bepi <pepicima@...>
To: synchronome1@groups.io
Sent: Sat, 14 Nov 2020 16:02
Subject: Re: [synchronomeelectricclock] The Impulse Roller & Shape of Pallet

Hal, to minimize the escapement error, in my synchronome it can be made undetectable, you need to carefully center the impulse around the phase corresponding to a vertical pendulum rod. Adding energy when it's all kinetic doesn't change the period in the small angle approximation.
This is why I was looking for a way to mechanically control the phase with precision. Thanks Neville about your answer, I am still looking for a way to do it with better accuracy than by hand, I guess I need to devise a simple process to do it.
I am not claiming it's a needed adjustment for best accuracy, the opposite, I think I reported long ago in this forum that minimizing the escapement error doesn't significantly affect the period in the short turn accuracy, even a large escapement error seems to be very repeatable in a synchronome.



On Nov 14, 2020, at 14:47, H Hal via groups.io <haal@...> wrote:

Don't worry Bepi,
I live in a constant state of confusion.
You are impulsing the pendulum at some point during its swing. There are some points (during the swing) that the impulse will be very useful and efficient OR other points where the impulse will be detrimental (the child pushed by dad on the swing gets higher and higher OR gets lower and lower to a stop because it is tea time).
The phase angle represents a point somewhere on that sine curve (which represents the position of the pendulum in time) where impulse may be given.
?

On 14/11/2020 13:11, Bepi wrote:
Hal, sorry for adding to the confusion, let me make it worse now. In my pseudo-synchronome I control the clock-cycle phase of the impulse by changing a time delay starting from the previous period vertical crossing but it's clearer to speak about a phase angle, as in the angle of the tangent rule, p.-

On Nov 14, 2020, at 13:46, H Hal via groups.io <haal@...> wrote:

hi Bepi,

can you explain the difference between phase and time in relation to impulse or are you using the terms interchangeably?

regards

hal
On 14/11/2020 12:42, Bepi wrote:
Ian who are Mr Parsons and Mr Ball and where can I read about their results? I agree that the shape is probably of little importance, more relevant is the location of the impulse in phase/time.
Does anybody know how to regulate the impulse phase in a synchronome in an easy, controllable and accurate way?
The shape might be of some relevance in terms of repeatability which boils down to absence of sharp corners. 
--
Bepi

--
Bepi

--
Bepi


Re: The Impulse Roller & Shape of Pallet

Ian Richardson
 

Hi All,

To add even further to the confusion, in Shortt's "free pendulum" clock, the impulse arrangement is the other way round!  The pallet (actually the flat surface of a Brocot jewel) rolls over and around the wheel.  It starts "dead" as a tangent to the wheel at the top, and falls down, rotating the wheel, until it drops off.  That has always seemed to me to be a better arrangement which could easily have been incorporated into an otherwise standard Synchronome.  Has anyone ever done that?

Ian R



-----Original Message-----
From: Bepi <pepicima@...>
To: synchronome1@groups.io
Sent: Sat, 14 Nov 2020 16:02
Subject: Re: [synchronomeelectricclock] The Impulse Roller & Shape of Pallet

Hal, to minimize the escapement error, in my synchronome it can be made undetectable, you need to carefully center the impulse around the phase corresponding to a vertical pendulum rod. Adding energy when it's all kinetic doesn't change the period in the small angle approximation.
This is why I was looking for a way to mechanically control the phase with precision. Thanks Neville about your answer, I am still looking for a way to do it with better accuracy than by hand, I guess I need to devise a simple process to do it.
I am not claiming it's a needed adjustment for best accuracy, the opposite, I think I reported long ago in this forum that minimizing the escapement error doesn't significantly affect the period in the short turn accuracy, even a large escapement error seems to be very repeatable in a synchronome.



On Nov 14, 2020, at 14:47, H Hal via groups.io <haal@...> wrote:

Don't worry Bepi,
I live in a constant state of confusion.
You are impulsing the pendulum at some point during its swing. There are some points (during the swing) that the impulse will be very useful and efficient OR other points where the impulse will be detrimental (the child pushed by dad on the swing gets higher and higher OR gets lower and lower to a stop because it is tea time).
The phase angle represents a point somewhere on that sine curve (which represents the position of the pendulum in time) where impulse may be given.
?

On 14/11/2020 13:11, Bepi wrote:
Hal, sorry for adding to the confusion, let me make it worse now. In my pseudo-synchronome I control the clock-cycle phase of the impulse by changing a time delay starting from the previous period vertical crossing but it's clearer to speak about a phase angle, as in the angle of the tangent rule, p.-

On Nov 14, 2020, at 13:46, H Hal via groups.io <haal@...> wrote:

hi Bepi,

can you explain the difference between phase and time in relation to impulse or are you using the terms interchangeably?

regards

hal
On 14/11/2020 12:42, Bepi wrote:
Ian who are Mr Parsons and Mr Ball and where can I read about their results? I agree that the shape is probably of little importance, more relevant is the location of the impulse in phase/time.
Does anybody know how to regulate the impulse phase in a synchronome in an easy, controllable and accurate way?
The shape might be of some relevance in terms of repeatability which boils down to absence of sharp corners. 
--
Bepi

--
Bepi

--
Bepi


Re: The Impulse Roller & Shape of Pallet

Bepi
 

Hal, to minimize the escapement error, in my synchronome it can be made undetectable, you need to carefully center the impulse around the phase corresponding to a vertical pendulum rod. Adding energy when it's all kinetic doesn't change the period in the small angle approximation.
This is why I was looking for a way to mechanically control the phase with precision. Thanks Neville about your answer, I am still looking for a way to do it with better accuracy than by hand, I guess I need to devise a simple process to do it.
I am not claiming it's a needed adjustment for best accuracy, the opposite, I think I reported long ago in this forum that minimizing the escapement error doesn't significantly affect the period in the short turn accuracy, even a large escapement error seems to be very repeatable in a synchronome.



On Nov 14, 2020, at 14:47, H Hal via groups.io <haal@...> wrote:

Don't worry Bepi,

I live in a constant state of confusion.

You are impulsing the pendulum at some point during its swing. There are some points (during the swing) that the impulse will be very useful and efficient OR other points where the impulse will be detrimental (the child pushed by dad on the swing gets higher and higher OR gets lower and lower to a stop because it is tea time).

The phase angle represents a point somewhere on that sine curve (which represents the position of the pendulum in time) where impulse may be given.

?


On 14/11/2020 13:11, Bepi wrote:
Hal, sorry for adding to the confusion, let me make it worse now. In my pseudo-synchronome I control the clock-cycle phase of the impulse by changing a time delay starting from the previous period vertical crossing but it's clearer to speak about a phase angle, as in the angle of the tangent rule, p.-

On Nov 14, 2020, at 13:46, H Hal via groups.io <haal@...> wrote:

hi Bepi,


can you explain the difference between phase and time in relation to impulse or are you using the terms interchangeably?


regards


hal

On 14/11/2020 12:42, Bepi wrote:
Ian who are Mr Parsons and Mr Ball and where can I read about their results? I agree that the shape is probably of little importance, more relevant is the location of the impulse in phase/time.
Does anybody know how to regulate the impulse phase in a synchronome in an easy, controllable and accurate way?
The shape might be of some relevance in terms of repeatability which boils down to absence of sharp corners. 
--
Bepi


--
Bepi


--
Bepi


Re: The Impulse Roller & Shape of Pallet

John Haine
 

Hello Michael, nice to see you over here!  And thanks for the pictures.  Whether Hope-Jones actually tried to achieve a raised-cosine impulse profile is unclear, and Shortt's derivation seems to have been done during a talk by H-J (at the IEE I think) at which the latter was presumably describing the existing clock.  From what I can see in various publications, production pallets actually just machined the face to a circular profile, and somewhere there is a time-lapse video that shows the wheel impulsing where it actually lifts off the pallet around half way down the ramp, so what the impulse profile is for the standard synchronome I don't know.  My own version uses a stepper to lift and lower the arm and the timings are selected to make sure that the roller drops on the dead roll before the ramp and is lifted after.  The profile follows Shortt's prescription. 

You are right that you can cut the pallet using a cutter of the same diameter as the roller following the required path, however a complication is that the roller diameter doesn't correspond to standard end mills, so I generated the profile by computing the coordinates that cut the required curve corrected to use a 4 mm cutter.  (I got the chassis and mechanism of a Synchronome minus its pendulum on eBay.)  There are some pics here.  My pallet is flat, I just take care to line it up in the plane of swing.

Actually I am not convinced that the profile works as it is claimed.  When I started running my clock I set it up with the roller half way down the ramp with the pendulum stationary (moving the pendulum suspension to set).  I also had a "startup" routine that gave an impulse every 2 seconds to get the pendulum swinging then switched to maintaining mode.  However when I looked carefully at the timing, I discovered that the impulse gave a distinct phase advance which amounted to about 1 ms each time, which indicates that the impulse is early.  Eventually to counteract this I shifted the pendulum suspension to remove the phase shift, at which point the roller was no longer on the ramp at the centre position.  I haven't been able to explain this but I wonder if Shortt's theory doesn't take account of the dynamics of impulsing but is just a static view.

John.


Re: The Impulse Roller & Shape of Pallet

H Hal
 

Don't worry Bepi,

I live in a constant state of confusion.

You are impulsing the pendulum at some point during its swing. There are some points (during the swing) that the impulse will be very useful and efficient OR other points where the impulse will be detrimental (the child pushed by dad on the swing gets higher and higher OR gets lower and lower to a stop because it is tea time).

The phase angle represents a point somewhere on that sine curve (which represents the position of the pendulum in time) where impulse may be given.

?


On 14/11/2020 13:11, Bepi wrote:
Hal, sorry for adding to the confusion, let me make it worse now. In my pseudo-synchronome I control the clock-cycle phase of the impulse by changing a time delay starting from the previous period vertical crossing but it's clearer to speak about a phase angle, as in the angle of the tangent rule, p.-

On Nov 14, 2020, at 13:46, H Hal via groups.io <haal@...> wrote:

hi Bepi,


can you explain the difference between phase and time in relation to impulse or are you using the terms interchangeably?


regards


hal

On 14/11/2020 12:42, Bepi wrote:
Ian who are Mr Parsons and Mr Ball and where can I read about their results? I agree that the shape is probably of little importance, more relevant is the location of the impulse in phase/time.
Does anybody know how to regulate the impulse phase in a synchronome in an easy, controllable and accurate way?
The shape might be of some relevance in terms of repeatability which boils down to absence of sharp corners. 
--
Bepi


--
Bepi


Re: The Impulse Roller & Shape of Pallet

Neville Michie
 

The phase of the impulse can be adjusted by moving the pendulum sideways with the adjustment
above the suspension. I seem to remember instructions for adjusting this so the roller was
halfway down the slope when the pendulum was still and the latch tripped.
cheers,
Neville Michie

On 14 Nov 2020, at 23:42, Bepi <pepicima@gmail.com> wrote:

Ian who are Mr Parsons and Mr Ball and where can I read about their results? I agree that the shape is probably of little importance, more relevant is the location of the impulse in phase/time.
Does anybody know how to regulate the impulse phase in a synchronome in an easy, controllable and accurate way?
The shape might be of some relevance in terms of repeatability which boils down to absence of sharp corners.
--
Bepi


Re: The Impulse Roller & Shape of Pallet

Bepi
 

Hal, sorry for adding to the confusion, let me make it worse now. In my pseudo-synchronome I control the clock-cycle phase of the impulse by changing a time delay starting from the previous period vertical crossing but it's clearer to speak about a phase angle, as in the angle of the tangent rule, p.-

On Nov 14, 2020, at 13:46, H Hal via groups.io <haal@...> wrote:

hi Bepi,


can you explain the difference between phase and time in relation to impulse or are you using the terms interchangeably?


regards


hal

On 14/11/2020 12:42, Bepi wrote:
Ian who are Mr Parsons and Mr Ball and where can I read about their results? I agree that the shape is probably of little importance, more relevant is the location of the impulse in phase/time.
Does anybody know how to regulate the impulse phase in a synchronome in an easy, controllable and accurate way?
The shape might be of some relevance in terms of repeatability which boils down to absence of sharp corners. 
--
Bepi


--
Bepi


Re: The Impulse Roller & Shape of Pallet

Ian Richardson
 

Hi Bepi,

"Mr Parsons & Mr Ball" is a reference to the origins of Gent's "Pulsynetic" system, invented by Parsons & Ball.  Early Gent clocks carried the legend "Parson's Patent".

Cheers,
Ian



-----Original Message-----
From: Bepi <pepicima@...>
To: synchronome1@groups.io
Sent: Sat, 14 Nov 2020 13:42
Subject: Re: [synchronomeelectricclock] The Impulse Roller & Shape of Pallet

Ian who are Mr Parsons and Mr Ball and where can I read about their results? I agree that the shape is probably of little importance, more relevant is the location of the impulse in phase/time.
Does anybody know how to regulate the impulse phase in a synchronome in an easy, controllable and accurate way?
The shape might be of some relevance in terms of repeatability which boils down to absence of sharp corners. 
--
Bepi

501 - 520 of 1423