#### DC Power sources for a 1920's Synchronome master & Current Regulation?

Chris Wollaston

I'm still in the process of setting up my first Synchronome master and fortunately have found a supplier of a pukka pendulum & bob to replace the incorrect ones that came with it.  Now I'd welcome advice on what owners use for the DC supply for just the movement & it's integral clock?  I've been using a mains adaptor giving 5.2VDC at max 1A which I believe is too much as Miles mentions the set up voltage is 4.5VDC and 350mA.  My architectural case did not come fitted with a rheostat and again Miles doesn't show that 1920's models with any fitted current regulators inside the case.  Would 3 x D cells in series be adequate and last a decent time span, say a year+ and how do readers regulate their current? Rgds, Chris in E Sussex.

H Hal

Hi Chris,

Just because a power supply states 1A doe not mean it will pump out this much current and burn up a circuit.....assuming your circuit is sound

The circuit will draw the current it requires, providing the voltage is large enough to push it through the circuit.

5.2 is not hugely more than 4.5V

Ideally you would measure the current running through your circuit by feeding the current from the power supply through an ammeter (cheap digital ones are plentiful) then into the circuit.

To control the current ...reduce it...you need some form of resistance. You can use a variable resistor (chunky 2,3 or 4 Watts should do so it does not overheat) to tweak it until the 350mA is obtained, measure the value of the variable resistor (cheap digital multimeter used to measure current) and substitute the variable with a fixed resistor/s if you want, or keep the variable in the circuit to tweak in the future.

hal

On 02/03/2021 10:07, Chris Wollaston wrote:
I'm still in the process of setting up my first Synchronome master and fortunately have found a supplier of a pukka pendulum & bob to replace the incorrect ones that came with it.  Now I'd welcome advice on what owners use for the DC supply for just the movement & it's integral clock?  I've been using a mains adaptor giving 5.2VDC at max 1A which I believe is too much as Miles mentions the set up voltage is 4.5VDC and 350mA.  My architectural case did not come fitted with a rheostat and again Miles doesn't show that 1920's models with any fitted current regulators inside the case.  Would 3 x D cells in series be adequate and last a decent time span, say a year+ and how do readers regulate their current? Rgds, Chris in E Sussex.

John Hubert

OK, what I actually do is quite different as I have a large system with a distribution board etc.

If you have no risk/worry over power cuts, then a ‘wall wart’ type adaptor is fine.  If you get power cuts and with to run through then, then there must be a battery involved.  What I would (probably, and actually do for a single Silent Electric master running one salve dial) do for one clock is this;

Use a battery made up of AA cells (NiMh) - probably 4 cells if I was using no external slaves.  Use a 6 Volt (or slightly more if you have an old one to hand - I often use old redundant mobile phone chargers) ‘wall wart’ in series with a resistor to trickle charge the battery (charge at about 50 mA or less).  Run the clock from the battery, limiting the current to 300 - 330 mA with a suitable resistor. It is important that you think about getting the correct CURRENT - and use whatever Voltage needed to do that (typically about 4.5 Volts).   It will run for some days, even weeks on AA cells in the event of a power outage, but they are the most plentiful variety of rechargeable cell.

D cells are fine, and I do run a Bentley clock on a single D cell, where it runs happily for over a year.

Synchronome didn’t usually have a variable resistor fitted (though some late ones do.  Gents generally do have a variable resistor.

John

On 2 Mar 2021, at 10:07, Chris Wollaston <chris@...> wrote:

I'm still in the process of setting up my first Synchronome master and fortunately have found a supplier of a pukka pendulum & bob to replace the incorrect ones that came with it.  Now I'd welcome advice on what owners use for the DC supply for just the movement & it's integral clock?  I've been using a mains adaptor giving 5.2VDC at max 1A which I believe is too much as Miles mentions the set up voltage is 4.5VDC and 350mA.  My architectural case did not come fitted with a rheostat and again Miles doesn't show that 1920's models with any fitted current regulators inside the case.  Would 3 x D cells in series be adequate and last a decent time span, say a year+ and how do readers regulate their current? Rgds, Chris in E Sussex.

Thomas D. Erb

I'm not familiar with this type of master - but if it is really voltage-sensitive you can also use a diode - each diode will subtract .7 volts from the power supply.

alkaline batteries nominal voltage is 1.5VDC so 3 in series would give you 4.5VDC.

If the master really draws 350ma - you would'nt get a lot of life -

A D cell battery will give you 12000-18000 mAh

12000/350=34.2857 to 18000/350=51.4286

so between 34 and 50 hours of run time.

John Hubert

The master draws 300 - 350 mA …….. but the duty cycle is low; approximately 100 - 150 mS every 30 seconds, so the average is low.

J

On 2 Mar 2021, at 15:31, Thomas D. Erb <tde@...> wrote:

I'm not familiar with this type of master - but if it is really voltage-sensitive you can also use a diode - each diode will subtract .7 volts from the power supply.

alkaline batteries nominal voltage is 1.5VDC so 3 in series would give you 4.5VDC.

If the master really draws 350ma - you would'nt get a lot of life -
A D cell battery will give you 12000-18000 mAh
12000/350=34.2857 to 18000/350=51.4286

so between 34 and 50 hours of run time.

Andrew Nahum

I use 2 Duracells in series and the clock works well but it has to be in good adjustment on all the contact arm gaps etc. They last about a year. My impression is that more volts give more noise.
Andrew

On Tue, Mar 2, 2021 at 3:54 PM John Hubert <jfphubert@...> wrote:
The master draws 300 - 350 mA …….. but the duty cycle is low; approximately 100 - 150 mS every 30 seconds, so the average is low.

J

On 2 Mar 2021, at 15:31, Thomas D. Erb <tde@...> wrote:

I'm not familiar with this type of master - but if it is really voltage-sensitive you can also use a diode - each diode will subtract .7 volts from the power supply.

alkaline batteries nominal voltage is 1.5VDC so 3 in series would give you 4.5VDC.

If the master really draws 350ma - you would'nt get a lot of life -
A D cell battery will give you 12000-18000 mAh
12000/350=34.2857 to 18000/350=51.4286

so between 34 and 50 hours of run time.

Ian Richardson

I may be preaching to the converted, but clock systems such as the Synchronome are current controlled, and the recommended current through the system is 330mA.  The voltage applied will be dependent upon the number (and type) of slave dials in the series circuit. There is something to be said for using a voltage higher than the minimum required, and controlling the current with an appropriate series resistor.  In my house circuit, which includes a Synchronome (with 4 slaves) and a Gent (with 4 slaves and a programme unit) everything runs from a 50 v.d.c. supply.  I use physics lab type rheostats to control the current in each circuit to the relevant required values.

The current is not that critical and can be lower than the specified value, but ideally should not be too high otherwise the reset becomes a bit violent (and noisy!).  As Andrew pointed out, the adjustment of the air gaps in the master clock (and the slave dial mechanisms) should all be correct for reliable operation.  Should the current be too low, there is a "warning" given by the master clock in that the gravity arm will not reset promptly, but be helped by being nudged by the returning impulse pallet.  This is clearly audible both at the master clock and at any slaves in the circuit as, instead of a prompt "click" each half minute, there will be a prolonged click as the reset current starts and then ends about 1/2 second later.  Synchronome and Gent both produced a device called a "battery warning indicator" which sounded a bell or gong if the reset duration was too long.

Don't know if any of that helps, but I hope so.

Cheers,
Ian R
Somewhere in France

-----Original Message-----
From: Andrew Nahum <andrew.nahum@...>
To: synchronome1@groups.io
Sent: Tue, 2 Mar 2021 18:00
Subject: Re: [synchronomeelectricclock] DC Power sources for a 1920's Synchronome master & Current Regulation?

I use 2 Duracells in series and the clock works well but it has to be in good adjustment on all the contact arm gaps etc. They last about a year. My impression is that more volts give more noise.
Andrew

On Tue, Mar 2, 2021 at 3:54 PM John Hubert <jfphubert@...> wrote:
The master draws 300 - 350 mA …….. but the duty cycle is low; approximately 100 - 150 mS every 30 seconds, so the average is low.

J

On 2 Mar 2021, at 15:31, Thomas D. Erb <tde@...> wrote:

I'm not familiar with this type of master - but if it is really voltage-sensitive you can also use a diode - each diode will subtract .7 volts from the power supply.

alkaline batteries nominal voltage is 1.5VDC so 3 in series would give you 4.5VDC.

If the master really draws 350ma - you would'nt get a lot of life -
A D cell battery will give you 12000-18000 mAh
12000/350=34.2857 to 18000/350=51.4286

so between 34 and 50 hours of run time.

James

Hi Ian,

In your thoughts below you comment There is something to be said for using a voltage higher than the minimum required and controlling the current with an appropriate series resistor”  For my system (Master with ten slave dials) I have used a buck converter to adjust the voltage and don’t adjust the resistance.  As we all know, using ohms law, we can get 330mA by adjusting either voltage or resistance.  I have gone with voltage adjustment and have no added resistance in the circuit.

If I was to increase the voltage and then adjust the resistance what differences/benefits would their be?

Thanks,

James G

Somewhere in New Zealand

Sent from Mail for Windows 10

From: Ian Richardson via groups.io
Sent: Wednesday, 3 March 2021 7:53 am
To: synchronome1@groups.io
Subject: Re: [synchronomeelectricclock] DC Power sources for a 1920's Synchronome master & Current Regulation?

I may be preaching to the converted, but clock systems such as the Synchronome are current controlled, and the recommended current through the system is 330mA.  The voltage applied will be dependent upon the number (and type) of slave dials in the series circuit. There is something to be said for using a voltage higher than the minimum required, and controlling the current with an appropriate series resistor.  In my house circuit, which includes a Synchronome (with 4 slaves) and a Gent (with 4 slaves and a programme unit) everything runs from a 50 v.d.c. supply.  I use physics lab type rheostats to control the current in each circuit to the relevant required values.

The current is not that critical and can be lower than the specified value, but ideally should not be too high otherwise the reset becomes a bit violent (and noisy!).  As Andrew pointed out, the adjustment of the air gaps in the master clock (and the slave dial mechanisms) should all be correct for reliable operation.  Should the current be too low, there is a "warning" given by the master clock in that the gravity arm will not reset promptly, but be helped by being nudged by the returning impulse pallet.  This is clearly audible both at the master clock and at any slaves in the circuit as, instead of a prompt "click" each half minute, there will be a prolonged click as the reset current starts and then ends about 1/2 second later.  Synchronome and Gent both produced a device called a "battery warning indicator" which sounded a bell or gong if the reset duration was too long.

Don't know if any of that helps, but I hope so.

Cheers,

Ian R

Somewhere in France

-----Original Message-----
From: Andrew Nahum <andrew.nahum@...>
To: synchronome1@groups.io
Sent: Tue, 2 Mar 2021 18:00
Subject: Re: [synchronomeelectricclock] DC Power sources for a 1920's Synchronome master & Current Regulation?

I use 2 Duracells in series and the clock works well but it has to be in good adjustment on all the contact arm gaps etc. They last about a year. My impression is that more volts give more noise.

Andrew

On Tue, Mar 2, 2021 at 3:54 PM John Hubert <jfphubert@...> wrote:

The master draws 300 - 350 mA …….. but the duty cycle is low; approximately 100 - 150 mS every 30 seconds, so the average is low.

J

On 2 Mar 2021, at 15:31, Thomas D. Erb <tde@...> wrote:

I'm not familiar with this type of master - but if it is really voltage-sensitive you can also use a diode - each diode will subtract .7 volts from the power supply.

alkaline batteries nominal voltage is 1.5VDC so 3 in series would give you 4.5VDC.

If the master really draws 350ma - you would'nt get a lot of life -

A D cell battery will give you 12000-18000 mAh

12000/350=34.2857 to 18000/350=51.4286

so between 34 and 50 hours of run time.

neil

hi James,
Const current is better in this application as it takes care of resistance changes in the circuit due to temperature, and more importantly, contact resistance, points etc.
if a resistor is included in the circuit, and the voltage is increased, the circuit becomes less sensitive to changes in contact resistance, dirty point etc, especially if the included resistor is high compared to the reset of the circuit.

There is also the advantage that a short circuit somewhere won't destroy your power supply, or cause a fire, because the maxim,um current that can flow will be limited to a safe value by the included resistor.

neil
Also somewhere in New Zealand.

On 3/03/2021 11:07 am, James wrote:

Hi Ian,

In your thoughts below you comment There is something to be said for using a voltage higher than the minimum required and controlling the current with an appropriate series resistor”  For my system (Master with ten slave dials) I have used a buck converter to adjust the voltage and don’t adjust the resistance.  As we all know, using ohms law, we can get 330mA by adjusting either voltage or resistance.  I have gone with voltage adjustment and have no added resistance in the circuit.

If I was to increase the voltage and then adjust the resistance what differences/benefits would their be?

Thanks,

James G

Somewhere in New Zealand

Sent from Mail for Windows 10

From: Ian Richardson via groups.io
Sent: Wednesday, 3 March 2021 7:53 am
To: synchronome1@groups.io
Subject: Re: [synchronomeelectricclock] DC Power sources for a 1920's Synchronome master & Current Regulation?

I may be preaching to the converted, but clock systems such as the Synchronome are current controlled, and the recommended current through the system is 330mA.  The voltage applied will be dependent upon the number (and type) of slave dials in the series circuit. There is something to be said for using a voltage higher than the minimum required, and controlling the current with an appropriate series resistor.  In my house circuit, which includes a Synchronome (with 4 slaves) and a Gent (with 4 slaves and a programme unit) everything runs from a 50 v.d.c. supply.  I use physics lab type rheostats to control the current in each circuit to the relevant required values.

The current is not that critical and can be lower than the specified value, but ideally should not be too high otherwise the reset becomes a bit violent (and noisy!).  As Andrew pointed out, the adjustment of the air gaps in the master clock (and the slave dial mechanisms) should all be correct for reliable operation.  Should the current be too low, there is a "warning" given by the master clock in that the gravity arm will not reset promptly, but be helped by being nudged by the returning impulse pallet.  This is clearly audible both at the master clock and at any slaves in the circuit as, instead of a prompt "click" each half minute, there will be a prolonged click as the reset current starts and then ends about 1/2 second later.  Synchronome and Gent both produced a device called a "battery warning indicator" which sounded a bell or gong if the reset duration was too long.

Don't know if any of that helps, but I hope so.

Cheers,

Ian R

Somewhere in France

-----Original Message-----
From: Andrew Nahum <andrew.nahum@...>
To: synchronome1@groups.io
Sent: Tue, 2 Mar 2021 18:00
Subject: Re: [synchronomeelectricclock] DC Power sources for a 1920's Synchronome master & Current Regulation?

I use 2 Duracells in series and the clock works well but it has to be in good adjustment on all the contact arm gaps etc. They last about a year. My impression is that more volts give more noise.

Andrew

On Tue, Mar 2, 2021 at 3:54 PM John Hubert <jfphubert@...> wrote:

The master draws 300 - 350 mA …….. but the duty cycle is low; approximately 100 - 150 mS every 30 seconds, so the average is low.

J

On 2 Mar 2021, at 15:31, Thomas D. Erb <tde@...> wrote:

I'm not familiar with this type of master - but if it is really voltage-sensitive you can also use a diode - each diode will subtract .7 volts from the power supply.

alkaline batteries nominal voltage is 1.5VDC so 3 in series would give you 4.5VDC.

If the master really draws 350ma - you would'nt get a lot of life -

A D cell battery will give you 12000-18000 mAh

12000/350=34.2857 to 18000/350=51.4286

so between 34 and 50 hours of run time.

Tony Nixon

The benefit (if it is a benefit) of using a higher voltage, with a series resistance to limit the current to the correct value, is that it will decrease the time constant of the circuit and thus cause the solenoid to energise more quickly.  The steady state current in the circuit is simply the power supply voltage divided by the sum of of (the coil resistance, any additional resistance and the internal resistance of the power supply)
however, when the contact is made the current does not immediately achieve this value when the contact is closed because of the inductance of the coil.  The situation is further complicated by the fact that the inductance of the coil will vary as the armature approaches it.  If you use a series resistance equal to the resistance of the coil and double the 'normal' voltage you will still achieve the same steady sate current, but you will halve the 'time constant' of the circuit.  This may or may not be a good thing, I can certainly imagine the reset being noisier as the armature will be moving faster.

Tony

On 02/03/2021 22:07, James wrote:

Hi Ian,

In your thoughts below you comment There is something to be said for using a voltage higher than the minimum required and controlling the current with an appropriate series resistor”  For my system (Master with ten slave dials) I have used a buck converter to adjust the voltage and don’t adjust the resistance.  As we all know, using ohms law, we can get 330mA by adjusting either voltage or resistance.  I have gone with voltage adjustment and have no added resistance in the circuit.

If I was to increase the voltage and then adjust the resistance what differences/benefits would their be?

Thanks,

James G

Somewhere in New Zealand

Sent from Mail for Windows 10

From: Ian Richardson via groups.io
Sent: Wednesday, 3 March 2021 7:53 am
To: synchronome1@groups.io
Subject: Re: [synchronomeelectricclock] DC Power sources for a 1920's Synchronome master & Current Regulation?

I may be preaching to the converted, but clock systems such as the Synchronome are current controlled, and the recommended current through the system is 330mA.  The voltage applied will be dependent upon the number (and type) of slave dials in the series circuit. There is something to be said for using a voltage higher than the minimum required, and controlling the current with an appropriate series resistor.  In my house circuit, which includes a Synchronome (with 4 slaves) and a Gent (with 4 slaves and a programme unit) everything runs from a 50 v.d.c. supply.  I use physics lab type rheostats to control the current in each circuit to the relevant required values.

The current is not that critical and can be lower than the specified value, but ideally should not be too high otherwise the reset becomes a bit violent (and noisy!).  As Andrew pointed out, the adjustment of the air gaps in the master clock (and the slave dial mechanisms) should all be correct for reliable operation.  Should the current be too low, there is a "warning" given by the master clock in that the gravity arm will not reset promptly, but be helped by being nudged by the returning impulse pallet.  This is clearly audible both at the master clock and at any slaves in the circuit as, instead of a prompt "click" each half minute, there will be a prolonged click as the reset current starts and then ends about 1/2 second later.  Synchronome and Gent both produced a device called a "battery warning indicator" which sounded a bell or gong if the reset duration was too long.

Don't know if any of that helps, but I hope so.

Cheers,

Ian R

Somewhere in France

-----Original Message-----
From: Andrew Nahum <andrew.nahum@...>
To: synchronome1@groups.io
Sent: Tue, 2 Mar 2021 18:00
Subject: Re: [synchronomeelectricclock] DC Power sources for a 1920's Synchronome master & Current Regulation?

I use 2 Duracells in series and the clock works well but it has to be in good adjustment on all the contact arm gaps etc. They last about a year. My impression is that more volts give more noise.

Andrew

On Tue, Mar 2, 2021 at 3:54 PM John Hubert <jfphubert@...> wrote:

The master draws 300 - 350 mA …….. but the duty cycle is low; approximately 100 - 150 mS every 30 seconds, so the average is low.

J

On 2 Mar 2021, at 15:31, Thomas D. Erb <tde@...> wrote:

I'm not familiar with this type of master - but if it is really voltage-sensitive you can also use a diode - each diode will subtract .7 volts from the power supply.

alkaline batteries nominal voltage is 1.5VDC so 3 in series would give you 4.5VDC.

If the master really draws 350ma - you would'nt get a lot of life -

A D cell battery will give you 12000-18000 mAh

12000/350=34.2857 to 18000/350=51.4286

so between 34 and 50 hours of run time.

Andrew Nahum

Ian
Many  thanks. Very useful. I should have pointed out that I was talking about driving a single master clock with no subsidiary slaves (except the clock’s own dial). I see now I installed this one in 1998 and it has been running on 3 volts reliably with occasional service since then. The joy of 3 volts is that you can install a Radiospares or Maplins holder for two D cells invisibly top right behind the dial and need no external lead  mains plug.  Of course if you are running slave dials it needs a proper current supply. I did acquire that clock with two nice slave dials but my heart sank at the thought of running more wire up and down the house on top of the various generations of internal phone extension cables. (Thank god for mobile telephony - and 5G!).  A

On 2 Mar 2021, at 18:53, Ian Richardson via groups.io <irichar361@...> wrote:

﻿
I may be preaching to the converted, but clock systems such as the Synchronome are current controlled, and the recommended current through the system is 330mA.  The voltage applied will be dependent upon the number (and type) of slave dials in the series circuit. There is something to be said for using a voltage higher than the minimum required, and controlling the current with an appropriate series resistor.  In my house circuit, which includes a Synchronome (with 4 slaves) and a Gent (with 4 slaves and a programme unit) everything runs from a 50 v.d.c. supply.  I use physics lab type rheostats to control the current in each circuit to the relevant required values.

The current is not that critical and can be lower than the specified value, but ideally should not be too high otherwise the reset becomes a bit violent (and noisy!).  As Andrew pointed out, the adjustment of the air gaps in the master clock (and the slave dial mechanisms) should all be correct for reliable operation.  Should the current be too low, there is a "warning" given by the master clock in that the gravity arm will not reset promptly, but be helped by being nudged by the returning impulse pallet.  This is clearly audible both at the master clock and at any slaves in the circuit as, instead of a prompt "click" each half minute, there will be a prolonged click as the reset current starts and then ends about 1/2 second later.  Synchronome and Gent both produced a device called a "battery warning indicator" which sounded a bell or gong if the reset duration was too long.

Don't know if any of that helps, but I hope so.

Cheers,
Ian R
Somewhere in France

-----Original Message-----
From: Andrew Nahum <andrew.nahum@...>
To: synchronome1@groups.io
Sent: Tue, 2 Mar 2021 18:00
Subject: Re: [synchronomeelectricclock] DC Power sources for a 1920's Synchronome master & Current Regulation?

I use 2 Duracells in series and the clock works well but it has to be in good adjustment on all the contact arm gaps etc. They last about a year. My impression is that more volts give more noise.
Andrew

On Tue, Mar 2, 2021 at 3:54 PM John Hubert <jfphubert@...> wrote:
The master draws 300 - 350 mA …….. but the duty cycle is low; approximately 100 - 150 mS every 30 seconds, so the average is low.

J

On 2 Mar 2021, at 15:31, Thomas D. Erb <tde@...> wrote:

I'm not familiar with this type of master - but if it is really voltage-sensitive you can also use a diode - each diode will subtract .7 volts from the power supply.

alkaline batteries nominal voltage is 1.5VDC so 3 in series would give you 4.5VDC.

If the master really draws 350ma - you would'nt get a lot of life -
A D cell battery will give you 12000-18000 mAh
12000/350=34.2857 to 18000/350=51.4286

so between 34 and 50 hours of run time.

James

Hi,

Having the system in the house you become very familiar with the sound and now only notice it when it changes - even very slightly.

I have noted when the sound changes I can see that the speed of the armature has changed too.  Always assumed that this was due to a variation of voltage from the buck converter (which the manufacture says is not meant to happen).  Did not consider changes to the circuit resistance with temperature and moving position of the armature.

Tony, when you say add a resistor equal to the resistance of the coil, do you mean just the coil or the resistance of the complete circuit?  If I am aiming to double the voltage, would I need to double the entire circuit resistance?

James

Somewhere in the home office

Sent from Mail for Windows 10

From: neil
Sent: Wednesday, 3 March 2021 11:35 am
To: synchronome1@groups.io
Subject: Re: [synchronomeelectricclock] DC Power sources for a 1920's Synchronome master & Current Regulation?

hi James,
Const current is better in this application as it takes care of resistance changes in the circuit due to temperature, and more importantly, contact resistance, points etc.
if a resistor is included in the circuit, and the voltage is increased, the circuit becomes less sensitive to changes in contact resistance, dirty point etc, especially if the included resistor is high compared to the reset of the circuit.

There is also the advantage that a short circuit somewhere won't destroy your power supply, or cause a fire, because the maxim,um current that can flow will be limited to a safe value by the included resistor.

neil
Also somewhere in New Zealand.

` `

On 3/03/2021 11:07 am, James wrote:

Hi Ian,

In your thoughts below you comment There is something to be said for using a voltage higher than the minimum required and controlling the current with an appropriate series resistor”  For my system (Master with ten slave dials) I have used a buck converter to adjust the voltage and don’t adjust the resistance.  As we all know, using ohms law, we can get 330mA by adjusting either voltage or resistance.  I have gone with voltage adjustment and have no added resistance in the circuit.

If I was to increase the voltage and then adjust the resistance what differences/benefits would their be?

Thanks,

James G

Somewhere in New Zealand

Sent from Mail for Windows 10

From: Ian Richardson via groups.io
Sent: Wednesday, 3 March 2021 7:53 am
To: synchronome1@groups.io
Subject: Re: [synchronomeelectricclock] DC Power sources for a 1920's Synchronome master & Current Regulation?

I may be preaching to the converted, but clock systems such as the Synchronome are current controlled, and the recommended current through the system is 330mA.  The voltage applied will be dependent upon the number (and type) of slave dials in the series circuit. There is something to be said for using a voltage higher than the minimum required, and controlling the current with an appropriate series resistor.  In my house circuit, which includes a Synchronome (with 4 slaves) and a Gent (with 4 slaves and a programme unit) everything runs from a 50 v.d.c. supply.  I use physics lab type rheostats to control the current in each circuit to the relevant required values.

The current is not that critical and can be lower than the specified value, but ideally should not be too high otherwise the reset becomes a bit violent (and noisy!).  As Andrew pointed out, the adjustment of the air gaps in the master clock (and the slave dial mechanisms) should all be correct for reliable operation.  Should the current be too low, there is a "warning" given by the master clock in that the gravity arm will not reset promptly, but be helped by being nudged by the returning impulse pallet.  This is clearly audible both at the master clock and at any slaves in the circuit as, instead of a prompt "click" each half minute, there will be a prolonged click as the reset current starts and then ends about 1/2 second later.  Synchronome and Gent both produced a device called a "battery warning indicator" which sounded a bell or gong if the reset duration was too long.

Don't know if any of that helps, but I hope so.

Cheers,

Ian R

Somewhere in France

-----Original Message-----
From: Andrew Nahum <andrew.nahum@...>
To: synchronome1@groups.io
Sent: Tue, 2 Mar 2021 18:00
Subject: Re: [synchronomeelectricclock] DC Power sources for a 1920's Synchronome master & Current Regulation?

I use 2 Duracells in series and the clock works well but it has to be in good adjustment on all the contact arm gaps etc. They last about a year. My impression is that more volts give more noise.

Andrew

On Tue, Mar 2, 2021 at 3:54 PM John Hubert <jfphubert@...> wrote:

The master draws 300 - 350 mA …….. but the duty cycle is low; approximately 100 - 150 mS every 30 seconds, so the average is low.

J

On 2 Mar 2021, at 15:31, Thomas D. Erb <tde@...> wrote:

I'm not familiar with this type of master - but if it is really voltage-sensitive you can also use a diode - each diode will subtract .7 volts from the power supply.

alkaline batteries nominal voltage is 1.5VDC so 3 in series would give you 4.5VDC.

If the master really draws 350ma - you would'nt get a lot of life -

A D cell battery will give you 12000-18000 mAh

12000/350=34.2857 to 18000/350=51.4286

so between 34 and 50 hours of run time.

Andrew Nahum

Sound is certainly a pointer to health. But even if the voltage stays the same, the noise will
change as the clearances wander. There is the contact gap, but  also all the other dimensional
settings on the electrical re-arming side of the clock which are all set by felt-covered  buffer
screws so they are surely bound to compress and move over time and impulses?
Andrew

On 2 Mar 2021, at 23:19, James <wikitoria4501@...> wrote:

﻿

Hi,

Having the system in the house you become very familiar with the sound and now only notice it when it changes - even very slightly.

I have noted when the sound changes I can see that the speed of the armature has changed too.  Always assumed that this was due to a variation of voltage from the buck converter (which the manufacture says is not meant to happen).  Did not consider changes to the circuit resistance with temperature and moving position of the armature.

Tony, when you say add a resistor equal to the resistance of the coil, do you mean just the coil or the resistance of the complete circuit?  If I am aiming to double the voltage, would I need to double the entire circuit resistance?

James

Somewhere in the home office

Sent from Mail for Windows 10

From: neil
Sent: Wednesday, 3 March 2021 11:35 am
To: synchronome1@groups.io
Subject: Re: [synchronomeelectricclock] DC Power sources for a 1920's Synchronome master & Current Regulation?

hi James,
Const current is better in this application as it takes care of resistance changes in the circuit due to temperature, and more importantly, contact resistance, points etc.
if a resistor is included in the circuit, and the voltage is increased, the circuit becomes less sensitive to changes in contact resistance, dirty point etc, especially if the included resistor is high compared to the reset of the circuit.

There is also the advantage that a short circuit somewhere won't destroy your power supply, or cause a fire, because the maxim,um current that can flow will be limited to a safe value by the included resistor.

neil
Also somewhere in New Zealand.

` `

On 3/03/2021 11:07 am, James wrote:

Hi Ian,

In your thoughts below you comment There is something to be said for using a voltage higher than the minimum required and controlling the current with an appropriate series resistor”  For my system (Master with ten slave dials) I have used a buck converter to adjust the voltage and don’t adjust the resistance.  As we all know, using ohms law, we can get 330mA by adjusting either voltage or resistance.  I have gone with voltage adjustment and have no added resistance in the circuit.

If I was to increase the voltage and then adjust the resistance what differences/benefits would their be?

Thanks,

James G

Somewhere in New Zealand

Sent from Mail for Windows 10

From: Ian Richardson via groups.io
Sent: Wednesday, 3 March 2021 7:53 am
To: synchronome1@groups.io
Subject: Re: [synchronomeelectricclock] DC Power sources for a 1920's Synchronome master & Current Regulation?

I may be preaching to the converted, but clock systems such as the Synchronome are current controlled, and the recommended current through the system is 330mA.  The voltage applied will be dependent upon the number (and type) of slave dials in the series circuit. There is something to be said for using a voltage higher than the minimum required, and controlling the current with an appropriate series resistor.  In my house circuit, which includes a Synchronome (with 4 slaves) and a Gent (with 4 slaves and a programme unit) everything runs from a 50 v.d.c. supply.  I use physics lab type rheostats to control the current in each circuit to the relevant required values.

The current is not that critical and can be lower than the specified value, but ideally should not be too high otherwise the reset becomes a bit violent (and noisy!).  As Andrew pointed out, the adjustment of the air gaps in the master clock (and the slave dial mechanisms) should all be correct for reliable operation.  Should the current be too low, there is a "warning" given by the master clock in that the gravity arm will not reset promptly, but be helped by being nudged by the returning impulse pallet.  This is clearly audible both at the master clock and at any slaves in the circuit as, instead of a prompt "click" each half minute, there will be a prolonged click as the reset current starts and then ends about 1/2 second later.  Synchronome and Gent both produced a device called a "battery warning indicator" which sounded a bell or gong if the reset duration was too long.

Don't know if any of that helps, but I hope so.

Cheers,

Ian R

Somewhere in France

-----Original Message-----
From: Andrew Nahum <andrew.nahum@...>
To: synchronome1@groups.io
Sent: Tue, 2 Mar 2021 18:00
Subject: Re: [synchronomeelectricclock] DC Power sources for a 1920's Synchronome master & Current Regulation?

I use 2 Duracells in series and the clock works well but it has to be in good adjustment on all the contact arm gaps etc. They last about a year. My impression is that more volts give more noise.

Andrew

On Tue, Mar 2, 2021 at 3:54 PM John Hubert <jfphubert@...> wrote:

The master draws 300 - 350 mA …….. but the duty cycle is low; approximately 100 - 150 mS every 30 seconds, so the average is low.

J

On 2 Mar 2021, at 15:31, Thomas D. Erb <tde@...> wrote:

I'm not familiar with this type of master - but if it is really voltage-sensitive you can also use a diode - each diode will subtract .7 volts from the power supply.

alkaline batteries nominal voltage is 1.5VDC so 3 in series would give you 4.5VDC.

If the master really draws 350ma - you would'nt get a lot of life -

A D cell battery will give you 12000-18000 mAh

12000/350=34.2857 to 18000/350=51.4286

so between 34 and 50 hours of run time.

James

Is there a maximum voltage that you can put on a circuit? At what number of slave dials do you need to use a relay and a new power supply?

Regards
James

On Wed, 3 Mar 2021, 11:56 am Tony Nixon, <aknixon@...> wrote:
The benefit (if it is a benefit) of using a higher voltage, with a series resistance to limit the current to the correct value, is that it will decrease the time constant of the circuit and thus cause the solenoid to energise more quickly.  The steady state current in the circuit is simply the power supply voltage divided by the sum of of (the coil resistance, any additional resistance and the internal resistance of the power supply)
however, when the contact is made the current does not immediately achieve this value when the contact is closed because of the inductance of the coil.  The situation is further complicated by the fact that the inductance of the coil will vary as the armature approaches it.  If you use a series resistance equal to the resistance of the coil and double the 'normal' voltage you will still achieve the same steady sate current, but you will halve the 'time constant' of the circuit.  This may or may not be a good thing, I can certainly imagine the reset being noisier as the armature will be moving faster.

Tony

On 02/03/2021 22:07, James wrote:

Hi Ian,

In your thoughts below you comment There is something to be said for using a voltage higher than the minimum required and controlling the current with an appropriate series resistor”  For my system (Master with ten slave dials) I have used a buck converter to adjust the voltage and don’t adjust the resistance.  As we all know, using ohms law, we can get 330mA by adjusting either voltage or resistance.  I have gone with voltage adjustment and have no added resistance in the circuit.

If I was to increase the voltage and then adjust the resistance what differences/benefits would their be?

Thanks,

James G

Somewhere in New Zealand

Sent from Mail for Windows 10

From: Ian Richardson via groups.io
Sent: Wednesday, 3 March 2021 7:53 am
To: synchronome1@groups.io
Subject: Re: [synchronomeelectricclock] DC Power sources for a 1920's Synchronome master & Current Regulation?

I may be preaching to the converted, but clock systems such as the Synchronome are current controlled, and the recommended current through the system is 330mA.  The voltage applied will be dependent upon the number (and type) of slave dials in the series circuit. There is something to be said for using a voltage higher than the minimum required, and controlling the current with an appropriate series resistor.  In my house circuit, which includes a Synchronome (with 4 slaves) and a Gent (with 4 slaves and a programme unit) everything runs from a 50 v.d.c. supply.  I use physics lab type rheostats to control the current in each circuit to the relevant required values.

The current is not that critical and can be lower than the specified value, but ideally should not be too high otherwise the reset becomes a bit violent (and noisy!).  As Andrew pointed out, the adjustment of the air gaps in the master clock (and the slave dial mechanisms) should all be correct for reliable operation.  Should the current be too low, there is a "warning" given by the master clock in that the gravity arm will not reset promptly, but be helped by being nudged by the returning impulse pallet.  This is clearly audible both at the master clock and at any slaves in the circuit as, instead of a prompt "click" each half minute, there will be a prolonged click as the reset current starts and then ends about 1/2 second later.  Synchronome and Gent both produced a device called a "battery warning indicator" which sounded a bell or gong if the reset duration was too long.

Don't know if any of that helps, but I hope so.

Cheers,

Ian R

Somewhere in France

-----Original Message-----
From: Andrew Nahum <andrew.nahum@...>
To: synchronome1@groups.io
Sent: Tue, 2 Mar 2021 18:00
Subject: Re: [synchronomeelectricclock] DC Power sources for a 1920's Synchronome master & Current Regulation?

I use 2 Duracells in series and the clock works well but it has to be in good adjustment on all the contact arm gaps etc. They last about a year. My impression is that more volts give more noise.

Andrew

On Tue, Mar 2, 2021 at 3:54 PM John Hubert <jfphubert@...> wrote:

The master draws 300 - 350 mA …….. but the duty cycle is low; approximately 100 - 150 mS every 30 seconds, so the average is low.

J

On 2 Mar 2021, at 15:31, Thomas D. Erb <tde@...> wrote:

I'm not familiar with this type of master - but if it is really voltage-sensitive you can also use a diode - each diode will subtract .7 volts from the power supply.

alkaline batteries nominal voltage is 1.5VDC so 3 in series would give you 4.5VDC.

If the master really draws 350ma - you would'nt get a lot of life -

A D cell battery will give you 12000-18000 mAh

12000/350=34.2857 to 18000/350=51.4286

so between 34 and 50 hours of run time.

I have used the now common USB sockets that give 5V DC and at about 2A.  The circuit will only draw what it needs.  A Synchronome will draw about a third of an Amp and that is only when the contacts are made.  This is why they can run off batteries for months.

Simon

On Tue, 2 Mar 2021 at 22:07, James <wikitoria4501@...> wrote:

Hi Ian,

In your thoughts below you comment There is something to be said for using a voltage higher than the minimum required and controlling the current with an appropriate series resistor”  For my system (Master with ten slave dials) I have used a buck converter to adjust the voltage and don’t adjust the resistance.  As we all know, using ohms law, we can get 330mA by adjusting either voltage or resistance.  I have gone with voltage adjustment and have no added resistance in the circuit.

If I was to increase the voltage and then adjust the resistance what differences/benefits would their be?

Thanks,

James G

Somewhere in New Zealand

Sent from Mail for Windows 10

From: Ian Richardson via groups.io
Sent: Wednesday, 3 March 2021 7:53 am
To: synchronome1@groups.io
Subject: Re: [synchronomeelectricclock] DC Power sources for a 1920's Synchronome master & Current Regulation?

I may be preaching to the converted, but clock systems such as the Synchronome are current controlled, and the recommended current through the system is 330mA.  The voltage applied will be dependent upon the number (and type) of slave dials in the series circuit. There is something to be said for using a voltage higher than the minimum required, and controlling the current with an appropriate series resistor.  In my house circuit, which includes a Synchronome (with 4 slaves) and a Gent (with 4 slaves and a programme unit) everything runs from a 50 v.d.c. supply.  I use physics lab type rheostats to control the current in each circuit to the relevant required values.

The current is not that critical and can be lower than the specified value, but ideally should not be too high otherwise the reset becomes a bit violent (and noisy!).  As Andrew pointed out, the adjustment of the air gaps in the master clock (and the slave dial mechanisms) should all be correct for reliable operation.  Should the current be too low, there is a "warning" given by the master clock in that the gravity arm will not reset promptly, but be helped by being nudged by the returning impulse pallet.  This is clearly audible both at the master clock and at any slaves in the circuit as, instead of a prompt "click" each half minute, there will be a prolonged click as the reset current starts and then ends about 1/2 second later.  Synchronome and Gent both produced a device called a "battery warning indicator" which sounded a bell or gong if the reset duration was too long.

Don't know if any of that helps, but I hope so.

Cheers,

Ian R

Somewhere in France

-----Original Message-----
From: Andrew Nahum <andrew.nahum@...>
To: synchronome1@groups.io
Sent: Tue, 2 Mar 2021 18:00
Subject: Re: [synchronomeelectricclock] DC Power sources for a 1920's Synchronome master & Current Regulation?

I use 2 Duracells in series and the clock works well but it has to be in good adjustment on all the contact arm gaps etc. They last about a year. My impression is that more volts give more noise.

Andrew

On Tue, Mar 2, 2021 at 3:54 PM John Hubert <jfphubert@...> wrote:

The master draws 300 - 350 mA …….. but the duty cycle is low; approximately 100 - 150 mS every 30 seconds, so the average is low.

J

On 2 Mar 2021, at 15:31, Thomas D. Erb <tde@...> wrote:

I'm not familiar with this type of master - but if it is really voltage-sensitive you can also use a diode - each diode will subtract .7 volts from the power supply.

alkaline batteries nominal voltage is 1.5VDC so 3 in series would give you 4.5VDC.

If the master really draws 350ma - you would'nt get a lot of life -

A D cell battery will give you 12000-18000 mAh

12000/350=34.2857 to 18000/350=51.4286

so between 34 and 50 hours of run time.

--
Simon

H Hal

with suitable resistance you can use any voltage but sadly you will have to start sticking those yellow high voltage warning labels over the clock

those old style christmas tree lights connected in series, powered by mains, share the 110V or 230V equally to get their 2 or 3V to work are pretty but of course when one blows they all go off...and testing the sockets with a wet finger is a great early present.

hal uk

On 03/03/2021 08:21, James wrote:
Is there a maximum voltage that you can put on a circuit? At what number of slave dials do you need to use a relay and a new power supply?

Regards
James

On Wed, 3 Mar 2021, 11:56 am Tony Nixon, <aknixon@...> wrote:
The benefit (if it is a benefit) of using a higher voltage, with a series resistance to limit the current to the correct value, is that it will decrease the time constant of the circuit and thus cause the solenoid to energise more quickly.  The steady state current in the circuit is simply the power supply voltage divided by the sum of of (the coil resistance, any additional resistance and the internal resistance of the power supply)
however, when the contact is made the current does not immediately achieve this value when the contact is closed because of the inductance of the coil.  The situation is further complicated by the fact that the inductance of the coil will vary as the armature approaches it.  If you use a series resistance equal to the resistance of the coil and double the 'normal' voltage you will still achieve the same steady sate current, but you will halve the 'time constant' of the circuit.  This may or may not be a good thing, I can certainly imagine the reset being noisier as the armature will be moving faster.

Tony

On 02/03/2021 22:07, James wrote:

Hi Ian,

In your thoughts below you comment There is something to be said for using a voltage higher than the minimum required and controlling the current with an appropriate series resistor”  For my system (Master with ten slave dials) I have used a buck converter to adjust the voltage and don’t adjust the resistance.  As we all know, using ohms law, we can get 330mA by adjusting either voltage or resistance.  I have gone with voltage adjustment and have no added resistance in the circuit.

If I was to increase the voltage and then adjust the resistance what differences/benefits would their be?

Thanks,

James G

Somewhere in New Zealand

Sent from Mail for Windows 10

From: Ian Richardson via groups.io
Sent: Wednesday, 3 March 2021 7:53 am
To: synchronome1@groups.io
Subject: Re: [synchronomeelectricclock] DC Power sources for a 1920's Synchronome master & Current Regulation?

I may be preaching to the converted, but clock systems such as the Synchronome are current controlled, and the recommended current through the system is 330mA.  The voltage applied will be dependent upon the number (and type) of slave dials in the series circuit. There is something to be said for using a voltage higher than the minimum required, and controlling the current with an appropriate series resistor.  In my house circuit, which includes a Synchronome (with 4 slaves) and a Gent (with 4 slaves and a programme unit) everything runs from a 50 v.d.c. supply.  I use physics lab type rheostats to control the current in each circuit to the relevant required values.

The current is not that critical and can be lower than the specified value, but ideally should not be too high otherwise the reset becomes a bit violent (and noisy!).  As Andrew pointed out, the adjustment of the air gaps in the master clock (and the slave dial mechanisms) should all be correct for reliable operation.  Should the current be too low, there is a "warning" given by the master clock in that the gravity arm will not reset promptly, but be helped by being nudged by the returning impulse pallet.  This is clearly audible both at the master clock and at any slaves in the circuit as, instead of a prompt "click" each half minute, there will be a prolonged click as the reset current starts and then ends about 1/2 second later.  Synchronome and Gent both produced a device called a "battery warning indicator" which sounded a bell or gong if the reset duration was too long.

Don't know if any of that helps, but I hope so.

Cheers,

Ian R

Somewhere in France

-----Original Message-----
From: Andrew Nahum <andrew.nahum@...>
To: synchronome1@groups.io
Sent: Tue, 2 Mar 2021 18:00
Subject: Re: [synchronomeelectricclock] DC Power sources for a 1920's Synchronome master & Current Regulation?

I use 2 Duracells in series and the clock works well but it has to be in good adjustment on all the contact arm gaps etc. They last about a year. My impression is that more volts give more noise.

Andrew

On Tue, Mar 2, 2021 at 3:54 PM John Hubert <jfphubert@...> wrote:

The master draws 300 - 350 mA …….. but the duty cycle is low; approximately 100 - 150 mS every 30 seconds, so the average is low.

J

On 2 Mar 2021, at 15:31, Thomas D. Erb <tde@...> wrote:

I'm not familiar with this type of master - but if it is really voltage-sensitive you can also use a diode - each diode will subtract .7 volts from the power supply.

alkaline batteries nominal voltage is 1.5VDC so 3 in series would give you 4.5VDC.

If the master really draws 350ma - you would'nt get a lot of life -

A D cell battery will give you 12000-18000 mAh

12000/350=34.2857 to 18000/350=51.4286

so between 34 and 50 hours of run time.

John Hutchinson

I have a Synchronome master (no. 2750) with only its internal slave dial connected.  It runs off 3 alkaline (non-rechargeable) 'C' cells.  They are in a 3 cell holder on a little shelf in the top right corner of the case.  Each set of cells lasts 11 months, give or take a week.  I record when I change them and it's quite surprising how consistent the replacement interval is.  I think there are wide variations in the quality of alkaline batteries.  I used to just use cheap ones from Amazon etc but Duracells definitely last longer.

Tony Nixon

James,
I would be very surprised if you have to consider the change in circuit resistance due to temperature, I don't think this will vary to any appreciable degree. The inductance will probably vary as the armature moves (how much I have no idea) but there is little you can do about this.  It does not affect the ultimate value of the current, it affects only the profile of the current during the fraction of a second that the coil is energised.

Assuming that the current you have in your setup at present is correct, then if you want to double the voltage you would need to double the resistance of the entire series circuit (i.e. the armature, the slave on the door and and any remote slaves and their connecting wiring) by adding a resistor in series.  A variable resistor is best so that you can adjust it if you change the setup in future.

Tony

On 02/03/2021 23:19, James wrote:

Hi,

Having the system in the house you become very familiar with the sound and now only notice it when it changes - even very slightly.

I have noted when the sound changes I can see that the speed of the armature has changed too.  Always assumed that this was due to a variation of voltage from the buck converter (which the manufacture says is not meant to happen).  Did not consider changes to the circuit resistance with temperature and moving position of the armature.

Tony, when you say add a resistor equal to the resistance of the coil, do you mean just the coil or the resistance of the complete circuit?  If I am aiming to double the voltage, would I need to double the entire circuit resistance?

James

Somewhere in the home office

Sent from Mail for Windows 10

From: neil
Sent: Wednesday, 3 March 2021 11:35 am
To: synchronome1@groups.io
Subject: Re: [synchronomeelectricclock] DC Power sources for a 1920's Synchronome master & Current Regulation?

hi James,
Const current is better in this application as it takes care of resistance changes in the circuit due to temperature, and more importantly, contact resistance, points etc.
if a resistor is included in the circuit, and the voltage is increased, the circuit becomes less sensitive to changes in contact resistance, dirty point etc, especially if the included resistor is high compared to the reset of the circuit.

There is also the advantage that a short circuit somewhere won't destroy your power supply, or cause a fire, because the maxim,um current that can flow will be limited to a safe value by the included resistor.

neil
Also somewhere in New Zealand.

` `

On 3/03/2021 11:07 am, James wrote:

Hi Ian,

In your thoughts below you comment There is something to be said for using a voltage higher than the minimum required and controlling the current with an appropriate series resistor”  For my system (Master with ten slave dials) I have used a buck converter to adjust the voltage and don’t adjust the resistance.  As we all know, using ohms law, we can get 330mA by adjusting either voltage or resistance.  I have gone with voltage adjustment and have no added resistance in the circuit.

If I was to increase the voltage and then adjust the resistance what differences/benefits would their be?

Thanks,

James G

Somewhere in New Zealand

Sent from Mail for Windows 10

From: Ian Richardson via groups.io
Sent: Wednesday, 3 March 2021 7:53 am
To: synchronome1@groups.io
Subject: Re: [synchronomeelectricclock] DC Power sources for a 1920's Synchronome master & Current Regulation?

I may be preaching to the converted, but clock systems such as the Synchronome are current controlled, and the recommended current through the system is 330mA.  The voltage applied will be dependent upon the number (and type) of slave dials in the series circuit. There is something to be said for using a voltage higher than the minimum required, and controlling the current with an appropriate series resistor.  In my house circuit, which includes a Synchronome (with 4 slaves) and a Gent (with 4 slaves and a programme unit) everything runs from a 50 v.d.c. supply.  I use physics lab type rheostats to control the current in each circuit to the relevant required values.

The current is not that critical and can be lower than the specified value, but ideally should not be too high otherwise the reset becomes a bit violent (and noisy!).  As Andrew pointed out, the adjustment of the air gaps in the master clock (and the slave dial mechanisms) should all be correct for reliable operation.  Should the current be too low, there is a "warning" given by the master clock in that the gravity arm will not reset promptly, but be helped by being nudged by the returning impulse pallet.  This is clearly audible both at the master clock and at any slaves in the circuit as, instead of a prompt "click" each half minute, there will be a prolonged click as the reset current starts and then ends about 1/2 second later.  Synchronome and Gent both produced a device called a "battery warning indicator" which sounded a bell or gong if the reset duration was too long.

Don't know if any of that helps, but I hope so.

Cheers,

Ian R

Somewhere in France

-----Original Message-----
From: Andrew Nahum <andrew.nahum@...>
To: synchronome1@groups.io
Sent: Tue, 2 Mar 2021 18:00
Subject: Re: [synchronomeelectricclock] DC Power sources for a 1920's Synchronome master & Current Regulation?

I use 2 Duracells in series and the clock works well but it has to be in good adjustment on all the contact arm gaps etc. They last about a year. My impression is that more volts give more noise.

Andrew

On Tue, Mar 2, 2021 at 3:54 PM John Hubert <jfphubert@...> wrote:

The master draws 300 - 350 mA …….. but the duty cycle is low; approximately 100 - 150 mS every 30 seconds, so the average is low.

J

On 2 Mar 2021, at 15:31, Thomas D. Erb <tde@...> wrote:

I'm not familiar with this type of master - but if it is really voltage-sensitive you can also use a diode - each diode will subtract .7 volts from the power supply.

alkaline batteries nominal voltage is 1.5VDC so 3 in series would give you 4.5VDC.

If the master really draws 350ma - you would'nt get a lot of life -

A D cell battery will give you 12000-18000 mAh

12000/350=34.2857 to 18000/350=51.4286

so between 34 and 50 hours of run time.

John Hubert

Some years ago I made (and still use) some constant current units.  The design is from the LM317 application notes.  Details attached;

On 3 Mar 2021, at 16:08, Tony Nixon <aknixon@...> wrote:

James,
I would be very surprised if you have to consider the change in circuit resistance due to temperature, I don't think this will vary to any appreciable degree. The inductance will probably vary as the armature moves (how much I have no idea) but there is little you can do about this.  It does not affect the ultimate value of the current, it affects only the profile of the current during the fraction of a second that the coil is energised.

Assuming that the current you have in your setup at present is correct, then if you want to double the voltage you would need to double the resistance of the entire series circuit (i.e. the armature, the slave on the door and and any remote slaves and their connecting wiring) by adding a resistor in series.  A variable resistor is best so that you can adjust it if you change the setup in future.

Tony

On 02/03/2021 23:19, James wrote:
Hi,

Having the system in the house you become very familiar with the sound and now only notice it when it changes - even very slightly.

I have noted when the sound changes I can see that the speed of the armature has changed too.  Always assumed that this was due to a variation of voltage from the buck converter (which the manufacture says is not meant to happen).  Did not consider changes to the circuit resistance with temperature and moving position of the armature.

Tony, when you say add a resistor equal to the resistance of the coil, do you mean just the coil or the resistance of the complete circuit?  If I am aiming to double the voltage, would I need to double the entire circuit resistance?

James
Somewhere in the home office

Sent from Mail for Windows 10

From: neil
Sent: Wednesday, 3 March 2021 11:35 am
To: synchronome1@groups.io
Subject: Re: [synchronomeelectricclock] DC Power sources for a 1920's Synchronome master & Current Regulation?

hi James,
Const current is better in this application as it takes care of resistance changes in the circuit due to temperature, and more importantly, contact resistance, points etc.
if a resistor is included in the circuit, and the voltage is increased, the circuit becomes less sensitive to changes in contact resistance, dirty point etc, especially if the included resistor is high compared to the reset of the circuit.

There is also the advantage that a short circuit somewhere won't destroy your power supply, or cause a fire, because the maxim,um current that can flow will be limited to a safe value by the included resistor.

neil
Also somewhere in New Zealand.

` `
On 3/03/2021 11:07 am, James wrote:
Hi Ian,

In your thoughts below you comment There is something to be said for using a voltage higher than the minimum required and controlling the current with an appropriate series resistor”  For my system (Master with ten slave dials) I have used a buck converter to adjust the voltage and don’t adjust the resistance.  As we all know, using ohms law, we can get 330mA by adjusting either voltage or resistance.  I have gone with voltage adjustment and have no added resistance in the circuit.

If I was to increase the voltage and then adjust the resistance what differences/benefits would their be?

Thanks,
James G
Somewhere in New Zealand

Sent from Mail for Windows 10

From: Ian Richardson via groups.io
Sent: Wednesday, 3 March 2021 7:53 am
To: synchronome1@groups.io
Subject: Re: [synchronomeelectricclock] DC Power sources for a 1920's Synchronome master & Current Regulation?

I may be preaching to the converted, but clock systems such as the Synchronome are current controlled, and the recommended current through the system is 330mA.  The voltage applied will be dependent upon the number (and type) of slave dials in the series circuit. There is something to be said for using a voltage higher than the minimum required, and controlling the current with an appropriate series resistor.  In my house circuit, which includes a Synchronome (with 4 slaves) and a Gent (with 4 slaves and a programme unit) everything runs from a 50 v.d.c. supply.  I use physics lab type rheostats to control the current in each circuit to the relevant required values.

The current is not that critical and can be lower than the specified value, but ideally should not be too high otherwise the reset becomes a bit violent (and noisy!).  As Andrew pointed out, the adjustment of the air gaps in the master clock (and the slave dial mechanisms) should all be correct for reliable operation.  Should the current be too low, there is a "warning" given by the master clock in that the gravity arm will not reset promptly, but be helped by being nudged by the returning impulse pallet.  This is clearly audible both at the master clock and at any slaves in the circuit as, instead of a prompt "click" each half minute, there will be a prolonged click as the reset current starts and then ends about 1/2 second later.  Synchronome and Gent both produced a device called a "battery warning indicator" which sounded a bell or gong if the reset duration was too long.

Don't know if any of that helps, but I hope so.

Cheers,
Ian R
Somewhere in France

-----Original Message-----
From: Andrew Nahum <andrew.nahum@...>
To: synchronome1@groups.io
Sent: Tue, 2 Mar 2021 18:00
Subject: Re: [synchronomeelectricclock] DC Power sources for a 1920's Synchronome master & Current Regulation?

I use 2 Duracells in series and the clock works well but it has to be in good adjustment on all the contact arm gaps etc. They last about a year. My impression is that more volts give more noise.
Andrew

On Tue, Mar 2, 2021 at 3:54 PM John Hubert <jfphubert@...> wrote:
The master draws 300 - 350 mA …….. but the duty cycle is low; approximately 100 - 150 mS every 30 seconds, so the average is low.

J

On 2 Mar 2021, at 15:31, Thomas D. Erb <tde@...> wrote:

I'm not familiar with this type of master - but if it is really voltage-sensitive you can also use a diode - each diode will subtract .7 volts from the power supply.

alkaline batteries nominal voltage is 1.5VDC so 3 in series would give you 4.5VDC.

If the master really draws 350ma - you would'nt get a lot of life -
A D cell battery will give you 12000-18000 mAh
12000/350=34.2857 to 18000/350=51.4286

so between 34 and 50 hours of run time.

Andy Young

Gents recommended a maximum of 60v for a Pulsynetic system before using multiple loops and a distribution board.

Andy

On 2021-03-03 08:21, James wrote:
Is there a maximum voltage that you can put on a circuit? At what
number of slave dials do you need to use a relay and a new power
supply?

Regards

James

On Wed, 3 Mar 2021, 11:56 am Tony Nixon, <aknixon@cantab.net [8]>
wrote:

The benefit (if it is a benefit) of using a higher voltage, with a
series resistance to limit the current to the correct value, is that
it will decrease the time constant of the circuit and thus cause the
solenoid to energise more quickly.  The steady state current in the
circuit is simply the power supply voltage divided by the sum of of
(the coil resistance, any additional resistance and the internal
resistance of the power supply)
however, when the contact is made the current does not immediately
achieve this value when the contact is closed because of the
inductance of the coil.  The situation is further complicated by
the fact that the inductance of the coil will vary as the armature
approaches it.  If you use a series resistance equal to the
resistance of the coil and double the 'normal' voltage you will
still achieve the same steady sate current, but you will halve the
'time constant' of the circuit.  This may or may not be a good
thing, I can certainly imagine the reset being noisier as the
armature will be moving faster.

Tony

On 02/03/2021 22:07, James wrote:

Hi Ian,

In your thoughts below you comment _“__There is something to be
said for using a voltage higher than the minimum required_ _and
controlling the current with an appropriate series resistor”_
For my system (Master with ten slave dials) I have used a buck
converter to adjust the voltage and don’t adjust the
resistance.  As we all know, using ohms law, we can get 330mA by
adjusting either voltage or resistance.  I have gone with voltage
adjustment and have no added resistance in the circuit.

If I was to increase the voltage and then adjust the resistance
what differences/benefits would their be?

Thanks,

James G

Somewhere in New Zealand

Sent from Mail [2] for Windows 10

FROM: Ian Richardson via groups.io [3]
SENT: Wednesday, 3 March 2021 7:53 am
TO: synchronome1@groups.io [4]
SUBJECT: Re: [synchronomeelectricclock] DC Power sources for a
1920's Synchronome master & Current Regulation?

I may be preaching to the converted, but clock systems such as the
Synchronome are _CURRENT_ controlled, and the recommended current
through the system is 330mA.  The voltage applied will be
dependent upon the number (and type) of slave dials in the series
circuit. There is something to be said for using a voltage higher
than the minimum required, and controlling the current with an
appropriate series resistor.  In my house circuit, which includes
a Synchronome (with 4 slaves) and a Gent (with 4 slaves and a
programme unit) everything runs from a 50 v.d.c. supply.  I use
physics lab type rheostats to control the current in each circuit
to the relevant required values.

The current is not that critical and can be lower than the
specified value, but ideally should not be too high otherwise the
reset becomes a bit violent (and noisy!).  As Andrew pointed out,
the adjustment of the air gaps in the master clock (and the slave
dial mechanisms) should all be correct for reliable operation.
Should the current be too low, there is a "warning" given by the
master clock in that the gravity arm will not reset promptly, but
be helped by being nudged by the returning impulse pallet.  This
is clearly audible both at the master clock and at any slaves in
the circuit as, instead of a prompt "click" each half minute,
there will be a prolonged click as the reset current starts and
then ends about 1/2 second later.  Synchronome and Gent both
produced a device called a "battery warning indicator" which
sounded a bell or gong if the reset duration was too long.

Don't know if any of that helps, but I hope so.

Cheers,

Ian R

Somewhere in France

-----Original Message-----
From: Andrew Nahum <andrew.nahum@gmail.com> [5]
To: synchronome1@groups.io [6]
Sent: Tue, 2 Mar 2021 18:00
Subject: Re: [synchronomeelectricclock] DC Power sources for a
1920's Synchronome master & Current Regulation?

I use 2 Duracells in series and the clock works well but it has to
be in good adjustment on all the contact arm gaps etc. They last
about a year. My impression is that more volts give more noise.

Andrew

On Tue, Mar 2, 2021 at 3:54 PM John Hubert <jfphubert@gmail.com
[7]> wrote:

The master draws 300 - 350 mA …….. but the duty cycle is
low; approximately 100 - 150 mS every 30 seconds, so the average
is low.

J

On 2 Mar 2021, at 15:31, Thomas D. Erb <tde@electrictime.com
[1]> wrote:

I'm not familiar with this type of master - but if it is
really voltage-sensitive you can also use a diode - each diode
will subtract .7 volts from the power supply.

alkaline batteries nominal voltage is 1.5VDC so 3 in series
would give you 4.5VDC.

If the master really draws 350ma - you would'nt get a lot of
life -

A D cell battery will give you 12000-18000 mAh

12000/350=34.2857 to 18000/350=51.4286

so between 34 and 50 hours of run time.

 1 - 20 of 20