Date   

Re: Sticking reset

Brooke Clarke
 

Hi Brian:

The sluggishness of the movement indicates that you are driving the clock with the minimum voltage needed to get the correct current based on the coil resistance.  You will get much snappier performance, i.e. more solid operation if the loop voltage is 5 to 10 times higher which requires the addition of a carbon resistor in order to maintain the correct current.  Technically you are lowering the loop time constant since T = L/R.  For example see this test where a capacitor is charged to a known voltage then applied to the coil through a resistor chosen so that the coil current is the nominal value: https://youtu.be/wwFhpL7JEk4

--
Have Fun,

Brooke Clarke
https://www.PRC68.com
axioms:
1. The extent to which you can fix or improve something will be limited by how well you understand how it works.
2. Everybody, with no exceptions, holds false beliefs.


Re: Sticking reset

Andrew Nahum
 

I have had similar sticking on occasion. It seemed to be an electromagnetic phenomenon that developed because the ‘dwell’ of the closed contacts was too long. I have found over the years that  it’s always best to check or re-set all the gaps or clearances in the mechanism rather than use intuition to try and address a problem with particular adjustments. 


On 29 Jul 2021, at 22:23, John Hubert <jfphubert@...> wrote:

The correct adjustments are given here;



On 29 Jul 2021, at 22:09, Brian Cracknell <brcracknell@...> wrote:

Hello, I am having issues with my clock again. It runs fine for a while and then starts sticking as shown in this Youtube video (link below). The armature does not get grabbed by the coils properly when it should be impulsed leading to the ugly delay evident in the video which has adverse effects on timekeeping.

The current in the system is set to 330mA. Everything is clean; I have tried two separate power sources with the same result. I am currently using a mains plug-in transformer/rectifier running at 4.5 volts output with appropriate resistors. 

Previously I have fixed this issue by adjusting the backstop screw for the armature to being it closer to the coils and also adjusting the contact screw to move that the other way to keep the gap constant. That worked for a while but now the fault has reoccured. I always make sure that the screws are tightly locked in place after each adjustment so I do not think they are wobbling and reverting to a bad state.

Frustratingly, the "stickiness" may well disappear for a while the following day without any intervention and the gravity arm reverts to a healthy briskness in its reset. The improvement is generally short lived.

I would welcome any opinions.

https://youtu.be/cExBOStyNdU

Thanks 
Brian


Re: Sticking reset

H Hal
 

My first thought is one of poor electrical contact, are the contacts in good order..polished and clean, not cleaned with any abrasive wet/dry etc but clean, no oxidation.


I would then remove the pendulum and lower the gravity arm by hand very slowly to see if it makes contact and how well it makes contact...you can measure the current whilst doing this to see if it is reduced


is your current limited by a rheostat?  these also have contacts which may be in need of cleaning



hal

uk

On 29/07/2021 22:09, Brian Cracknell wrote:
Hello, I am having issues with my clock again. It runs fine for a while and then starts sticking as shown in this Youtube video (link below). The armature does not get grabbed by the coils properly when it should be impulsed leading to the ugly delay evident in the video which has adverse effects on timekeeping.

The current in the system is set to 330mA. Everything is clean; I have tried two separate power sources with the same result. I am currently using a mains plug-in transformer/rectifier running at 4.5 volts output with appropriate resistors. 

Previously I have fixed this issue by adjusting the backstop screw for the armature to being it closer to the coils and also adjusting the contact screw to move that the other way to keep the gap constant. That worked for a while but now the fault has reoccured. I always make sure that the screws are tightly locked in place after each adjustment so I do not think they are wobbling and reverting to a bad state.

Frustratingly, the "stickiness" may well disappear for a while the following day without any intervention and the gravity arm reverts to a healthy briskness in its reset. The improvement is generally short lived.

I would welcome any opinions.

https://youtu.be/cExBOStyNdU

Thanks 
Brian


Re: Sticking reset

Ian Richardson
 

Hi Brian,

There is an ancient proverb which says, "if all else fails, read the instructions".

Others may contribute, but for a start I attach a pdf file of a sketch I made years ago showing the settings for the buffers, air gaps etc.  As your current seems to be correct, maybe you could try adjusting these settings.

The only other thing is to try slackening the gravity arm return spring.  Finally, make sure that the rest buffer is clean and that the armature isn't sticking to it.  Other than that, I've noting more to offer.

Good luck,
Ian R
Auvergne, France


-----Original Message-----
From: Brian Cracknell <brcracknell@...>
To: synchronome1@groups.io
Sent: Thu, 29 Jul 2021 23:09
Subject: [synchronomeelectricclock] Sticking reset

Hello, I am having issues with my clock again. It runs fine for a while and then starts sticking as shown in this Youtube video (link below). The armature does not get grabbed by the coils properly when it should be impulsed leading to the ugly delay evident in the video which has adverse effects on timekeeping.

The current in the system is set to 330mA. Everything is clean; I have tried two separate power sources with the same result. I am currently using a mains plug-in transformer/rectifier running at 4.5 volts output with appropriate resistors. 

Previously I have fixed this issue by adjusting the backstop screw for the armature to being it closer to the coils and also adjusting the contact screw to move that the other way to keep the gap constant. That worked for a while but now the fault has reoccured. I always make sure that the screws are tightly locked in place after each adjustment so I do not think they are wobbling and reverting to a bad state.

Frustratingly, the "stickiness" may well disappear for a while the following day without any intervention and the gravity arm reverts to a healthy briskness in its reset. The improvement is generally short lived.

I would welcome any opinions.

https://youtu.be/cExBOStyNdU

Thanks 
Brian


Re: Sticking reset

John Hubert
 

On 29 Jul 2021, at 22:09, Brian Cracknell <brcracknell@...> wrote:

Hello, I am having issues with my clock again. It runs fine for a while and then starts sticking as shown in this Youtube video (link below). The armature does not get grabbed by the coils properly when it should be impulsed leading to the ugly delay evident in the video which has adverse effects on timekeeping.

The current in the system is set to 330mA. Everything is clean; I have tried two separate power sources with the same result. I am currently using a mains plug-in transformer/rectifier running at 4.5 volts output with appropriate resistors. 

Previously I have fixed this issue by adjusting the backstop screw for the armature to being it closer to the coils and also adjusting the contact screw to move that the other way to keep the gap constant. That worked for a while but now the fault has reoccured. I always make sure that the screws are tightly locked in place after each adjustment so I do not think they are wobbling and reverting to a bad state.

Frustratingly, the "stickiness" may well disappear for a while the following day without any intervention and the gravity arm reverts to a healthy briskness in its reset. The improvement is generally short lived.

I would welcome any opinions.

https://youtu.be/cExBOStyNdU

Thanks 
Brian


Sticking reset

Brian Cracknell
 

Hello, I am having issues with my clock again. It runs fine for a while and then starts sticking as shown in this Youtube video (link below). The armature does not get grabbed by the coils properly when it should be impulsed leading to the ugly delay evident in the video which has adverse effects on timekeeping.

The current in the system is set to 330mA. Everything is clean; I have tried two separate power sources with the same result. I am currently using a mains plug-in transformer/rectifier running at 4.5 volts output with appropriate resistors. 

Previously I have fixed this issue by adjusting the backstop screw for the armature to being it closer to the coils and also adjusting the contact screw to move that the other way to keep the gap constant. That worked for a while but now the fault has reoccured. I always make sure that the screws are tightly locked in place after each adjustment so I do not think they are wobbling and reverting to a bad state.

Frustratingly, the "stickiness" may well disappear for a while the following day without any intervention and the gravity arm reverts to a healthy briskness in its reset. The improvement is generally short lived.

I would welcome any opinions.

https://youtu.be/cExBOStyNdU

Thanks 
Brian


Re: M4 Turret movement resistor puzzle.

Peter Torry
 

When switching high current and or inductive loads it was usual to fit a mercury switch as then can cope with most "nasty" loads particularly when breaking high currents.  They were also fitted in order to stretch the impulse to  the turret movements to allow sufficient time for the slower movement to operate correctly.  If it is of help I can post an image of one - when I can find my camera !

Regards

Peter


On 26/07/2021 20:21, John Hubert wrote:
Two points here.  Firstly Robert (Bob) Miles book was compiled from the material he had available.  There are quite limited records for Synchronome.  It is possible he worked mainly from the hardware he had access to rather than detailed drawings and specifications.

Secondly, the ’norm’ (Synchronome) is to have resistor approximately 10 times the resistance of the coil in parallel for spark suppression.  Possibly that was fitted in your case.  Do you know the coil resistance?

I believe (and someone will no doubt correct me if I am wrong) that it was common in later days to have an “mercury delay” for big dial movements - and this may have removed the worry over sparks?

On 26 Jul 2021, at 19:53, Simon Allen <simon.sallen@...> wrote:

I am seeking to restore an M4 turret movement.  Robert Miles in his book says that it did not have a resistor connected in parallel with the coil.  My one does.  Across the two terminals connected in parallel to the coil is a 250 ohm resistor.  What was its purpose?


Re: M4 Turret movement resistor puzzle.

John Hubert
 

As a further thought, is it possible that the large movements - that would be installed very often large existing dials might have the resistor fitted by the installer when completing the installation, rather than fitted to the movement prior to delivery?

On 26 Jul 2021, at 20:21, John Hubert via groups.io <jfphubert@...> wrote:

Two points here.  Firstly Robert (Bob) Miles book was compiled from the material he had available.  There are quite limited records for Synchronome.  It is possible he worked mainly from the hardware he had access to rather than detailed drawings and specifications.

Secondly, the ’norm’ (Synchronome) is to have resistor approximately 10 times the resistance of the coil in parallel for spark suppression.  Possibly that was fitted in your case.  Do you know the coil resistance?

I believe (and someone will no doubt correct me if I am wrong) that it was common in later days to have an “mercury delay” for big dial movements - and this may have removed the worry over sparks?

On 26 Jul 2021, at 19:53, Simon Allen <simon.sallen@...> wrote:

I am seeking to restore an M4 turret movement.  Robert Miles in his book says that it did not have a resistor connected in parallel with the coil.  My one does.  Across the two terminals connected in parallel to the coil is a 250 ohm resistor.  What was its purpose?



Re: M4 Turret movement resistor puzzle.

Darren Conway
 

Hi

A resistor was used to suppress sparks across the contacts as they opened. Sparks erode the contacts.

If they had diodes available then, they would have used them.  That is what you should use instead of a resistor.


Regards

Darren Conway
New Zealand

On 27.07.21 6:53 am, Simon Allen wrote:
I am seeking to restore an M4 turret movement.  Robert Miles in his book says that it did not have a resistor connected in parallel with the coil.  My one does.  Across the two terminals connected in parallel to the coil is a 250 ohm resistor.  What was its purpose?

Virus-free. www.avast.com


Re: M4 Turret movement resistor puzzle.

John Hubert
 

Two points here.  Firstly Robert (Bob) Miles book was compiled from the material he had available.  There are quite limited records for Synchronome.  It is possible he worked mainly from the hardware he had access to rather than detailed drawings and specifications.

Secondly, the ’norm’ (Synchronome) is to have resistor approximately 10 times the resistance of the coil in parallel for spark suppression.  Possibly that was fitted in your case.  Do you know the coil resistance?

I believe (and someone will no doubt correct me if I am wrong) that it was common in later days to have an “mercury delay” for big dial movements - and this may have removed the worry over sparks?

On 26 Jul 2021, at 19:53, Simon Allen <simon.sallen@...> wrote:

I am seeking to restore an M4 turret movement.  Robert Miles in his book says that it did not have a resistor connected in parallel with the coil.  My one does.  Across the two terminals connected in parallel to the coil is a 250 ohm resistor.  What was its purpose?


M4 Turret movement resistor puzzle.

 

I am seeking to restore an M4 turret movement.  Robert Miles in his book says that it did not have a resistor connected in parallel with the coil.  My one does.  Across the two terminals connected in parallel to the coil is a 250 ohm resistor.  What was its purpose?


Re: Help needed in Narborough , Leicestershire

H Hal
 

Hi James,


I am in Market Harborough Leics and may be able to help the chap but not immediately...perhaps in a few weeks but an email conversation may be of help in the meantime


regards


hal

On 21/07/2021 08:33, James Nye wrote:

Dear All,

 

I am sending the same message to the two obvious groups. I was contacted by a gentleman in Narborough, Leicestershire, who has inherited from his father a Synchronome which came from Poole power station originally. He did have it running, but moved house, and can no longer get it to run. I have supplied him with some written instructions – all material very well know to you all – but he regrets he has not succeeded. He has asked if I can assist in finding anyone possibly close enough that might be able to help. Is there anyone out there that might? Send me a private email and I will put you directly in touch.

 

With many thanks,

 

James


Help needed in Narborough , Leicestershire

James Nye
 

Dear All,

 

I am sending the same message to the two obvious groups. I was contacted by a gentleman in Narborough, Leicestershire, who has inherited from his father a Synchronome which came from Poole power station originally. He did have it running, but moved house, and can no longer get it to run. I have supplied him with some written instructions – all material very well know to you all – but he regrets he has not succeeded. He has asked if I can assist in finding anyone possibly close enough that might be able to help. Is there anyone out there that might? Send me a private email and I will put you directly in touch.

 

With many thanks,

 

James


Re: Synchronome component, what is it?

POWERCLOCKS
 

Thanks for that. I hope to speak with an expert at a club meeting on Sunday. It was unfortunate some of the wiring had been removed before I received this clock so I could not just clean and replace stuff. Electronics. Not my strong point.
GJP


From: synchronome1@groups.io <synchronome1@groups.io> on behalf of John Hubert <jfphubert@...>
Sent: Friday, July 16, 2021 5:55:34 PM
To: synchronome1@groups.io <synchronome1@groups.io>
Subject: Re: [synchronomeelectricclock] Synchronome component, what is it?
 
Hi Graeme,

There is an active Electric Clock group in Australia under the Australian Antiquarian Horological Society, with contacts to the AHS in the UK.  https://aahs.org.au/ and the EHG group therein https://aahs.org.au/ehg-sydney/. That would probably be your best source of knowledge on your Australian built clock.  They seem to have (at least in normal times) a very active membership.

The Australian Synchronomes have many differences to the UK ones, and that component is fine of the differences!  I believe it is a resistor (in effect a coil of resistance wire on a bobbin).  Similar ones were used here by other makers, the photo shows a resistor in a Silent Electric clock from circa 1920.  It is unusual to come across an Australian built Synchronome in the UK, though some do exist here.


Usually these are used for things like spark suppression - typically a resistance of about 10 x the coil resistance value connected in parallel with the coil.  AS to whether you ’need’ it - as you have used, modern diode suppress the sparks well - but the resistor is part of the originality.  Personally - on my clocks I always keep the resistor - but add a diode in a ‘removable’ way - typically just in the spring clips or terminals used for the wiring.

John

On 16 Jul 2021, at 03:14, POWERCLOCKS <powerclocks@...> wrote:

Hi, I hope you are all well and not suffering too badly in these trying times. This is my first post here, I am wanting to know what this part is on my early Synchronome and what does it do? I have the movement running quite well now using two back to back diodes for spark quench (Thanks Rod Elliott) and it is now time to attach the clocks slave movement so I need to know what this does? So do I need it?
Cheers from Australia.
Graeme Power
<Inkedthumbnail_20200611_093500_LI.jpg>


Re: Synchronome component, what is it?

John Hubert
 

Hi Graeme,

There is an active Electric Clock group in Australia under the Australian Antiquarian Horological Society, with contacts to the AHS in the UK.  https://aahs.org.au/ and the EHG group therein https://aahs.org.au/ehg-sydney/. That would probably be your best source of knowledge on your Australian built clock.  They seem to have (at least in normal times) a very active membership.

The Australian Synchronomes have many differences to the UK ones, and that component is fine of the differences!  I believe it is a resistor (in effect a coil of resistance wire on a bobbin).  Similar ones were used here by other makers, the photo shows a resistor in a Silent Electric clock from circa 1920.  It is unusual to come across an Australian built Synchronome in the UK, though some do exist here.


Usually these are used for things like spark suppression - typically a resistance of about 10 x the coil resistance value connected in parallel with the coil.  AS to whether you ’need’ it - as you have used, modern diode suppress the sparks well - but the resistor is part of the originality.  Personally - on my clocks I always keep the resistor - but add a diode in a ‘removable’ way - typically just in the spring clips or terminals used for the wiring.

John

On 16 Jul 2021, at 03:14, POWERCLOCKS <powerclocks@...> wrote:

Hi, I hope you are all well and not suffering too badly in these trying times. This is my first post here, I am wanting to know what this part is on my early Synchronome and what does it do? I have the movement running quite well now using two back to back diodes for spark quench (Thanks Rod Elliott) and it is now time to attach the clocks slave movement so I need to know what this does? So do I need it?
Cheers from Australia.
Graeme Power
<Inkedthumbnail_20200611_093500_LI.jpg>


Synchronome component, what is it?

POWERCLOCKS
 

Hi, I hope you are all well and not suffering too badly in these trying times. This is my first post here, I am wanting to know what this part is on my early Synchronome and what does it do? I have the movement running quite well now using two back to back diodes for spark quench (Thanks Rod Elliott) and it is now time to attach the clocks slave movement so I need to know what this does? So do I need it?
Cheers from Australia.
Graeme Power


Re: Bounce in gravity arm

Howard
 

Interesting use of computer mouse pad, I will have to keep one back before they become obsolete!
My clock doesn’t have the gravity stop but all suggestions welcome and would like to see clock with nichrome wire operation.
Howard


Re: Bounce in gravity arm

Eric Scace
 

   It’s pretty easy to adjust to eliminate almost all of the bounce, which helps quiet the clock.

   Another helpful step is to place a small dense foam pad on the stop for the gravity arm (located behind the pendulum rod). I used a hole punch to cut one from a pad of neoprene; e.g., a computer mouse pad. Of course one must back out the screw to compensate for the presence of the foam pad. This pad acts to decelerate the gravity arm, eliminate the bounce, and cut down the noise (acoustic and vibration).

   Similarly, neoprene pads around the armature that shoves the gravity arm will cut down the noise. Spring tensions and voltages can be reduced significantly for the armature as well, if one uses a regulated DC supply rather than a battery, whilst still maintaining reliable (but much quieter) reset of the gravity arm.

   Lastly, the click jewel that drops between the teeth of the count wheel can be quieted by adding a bit of weight on its counterbalancing arm. I used a piece of heatshrink, experimenting to find the length and position that resulted in the quietest, yet reliable, operation… and then locking the heatshrink in place with the heat gun.

   All of the above steps are completely reversible to restore the clock to as-built condition.

   A more aggressive step is to remove the solenoid entirely, replacing it with a length of nichrome wire attached to the reset armature. Current flow heats the nichrome, expanding it so that a tensioning spring causes the armature to reset the gravity arm during the time allotted by the pendulum movement. Interrupting the current when the gravity arm has latched up (using a pair of leaf contacts opened by the armature travel) causes the nichrome to shrink, with the spring returning the armature to its resting position. I haven’t built this (yet). It’s not a Synchronome design, but still electromechanical, FWIW.

— Eric

On 2021 Jul 05, at 12:59 , cicastol@... wrote:

Hi,
i've taken a slow mo  vid of my gravity arm, that little bouncing is not visible by naked eye, really smooth operation.

Ciro


Re: Bounce in gravity arm

cicastol@...
 

Hi,
i've taken a slow mo  vid of my gravity arm, that little bouncing is not visible by naked eye, really smooth operation.

Ciro


Re Advice on Driving a Slave.......

Chris Wollaston
 

Hi All, I'd like to mention that I've recently bought an EC4A Slave Clock Impulse Driver from a small private Cambs UK manufacturer which can be ordered from the web at electric-clocks.co.uk  There's a choice of having the driver powered by a battery or in my case I chose the version that requires an external low voltage DC PSU.  At the moment I've got it powered by a v low cost Chinese variable voltage PSU (less than £10 on eBay) and set at around 10VDC happily driving a Synchronome 12inch slave. You can vary the pulse length; 62, 125 or 250ms and pulses every 1 min or 30secs to suit your device, all set up with links inside the driver case. I'm pleased with it especially as my Synchronome master has decided to stop running after a couple of weeks! I could send some pics if req'd? Bests, Chris in E Sussex.

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