IBM/ITR master clocks - UK Vintage Radio Repair and Restoration Discussion Forum

osx86apple · 25th Feb 2024, 5:02 pm

Hi everyone,

I have a couple of IBM/ITR master clocks and wondered whether I’d get away with powering each of the a 24V transformer that’s designed to power LED lighting?

Reason being, they are pretty low profile units and would fit quite nicely in the casing!

Just wondered how they might behave in this application? I’m not driving slave clocks so it’s only to energise the coil once a minute so the clocks can self wind.

mark_in_manc · 25th Feb 2024, 5:34 pm

I'm not quite clear on your question. The IBM/ITR master clocks I have seen (and one of which I use here) are long-case pendulum things which self-wind using an electric motor which runs constantly, driving an eccentric. I am not sure what voltage the motor is - there is a transformer in the case, so it might not be 240v. The master provides 24v pulses once a minute to drive the slaves, which are round things which hang on the wall. Which is it that you have? If the latter, and you want to retain the movement, you'll need a 24v pulse once a minute which will drive the hands around appropriately - no winding involved.
cheers
Mark

osx86apple · 25th Feb 2024, 5:48 pm

Hi Mark,

Thanks for the reply.

Mine are the later variant which has a mainspring vs the weight movement which I believe those were wound by a 240v motor. The type I have is similar to here http://www.hvtesla.com/masters/itr.html

Nickthedentist · 25th Feb 2024, 6:27 pm

I have one like that

Yes, mine too has a CHUNKY coil which is energised once a minute (via contacts on a cam driven by the timekeeping movement) to keep the mainspring wound.

These cases are huge and deep, so I'm not sure low-profile is a necessity.

Do your LED transformers actually give out 24V, or are they a constant voltage output?

Either way, you could rig one up with suitable current and voltage monitoring, then hold the switch contacts closed and see what current flows, and whether the voltage across the coil is near enough 24V.

Obviously, suitable fusing in the finished design is essential.

I bought mine for next to nothing 25 years ago and have only just got round to playing with it. Still not got as far as applying power yet though.

factory · 29th Feb 2024, 2:24 pm

The power supplies for LED lighting are normally constant current driver units, not constant voltage and chosen to meet the current required by the LED(s). Also some types of LED driver are not isolated from the mains, they might not be happy with an inductive load either.

David

osx86apple · 6th Apr 2024, 2:45 pm

Sorry for the late reply’s on this, been a hectic few months. An LED transformer has seemed to have worked very well with no adverse effects, with suitable fusing to be on the safe side

25th Feb 2024, 5:02 pm	#1
osx86apple Pentode Join Date: Dec 2014 Location: Torquay, Devon, UK. Posts: 148	IBM/ITR master clocks Hi everyone, I have a couple of IBM/ITR master clocks and wondered whether I’d get away with powering each of the a 24V transformer that’s designed to power LED lighting? Reason being, they are pretty low profile units and would fit quite nicely in the casing! Just wondered how they might behave in this application? I’m not driving slave clocks so it’s only to energise the coil once a minute so the clocks can self wind.

25th Feb 2024, 5:34 pm	#2
mark_in_manc Octode Join Date: Nov 2011 Location: Manchester, UK. Posts: 1,875	Re: IBM/ITR master clocks I'm not quite clear on your question. The IBM/ITR master clocks I have seen (and one of which I use here) are long-case pendulum things which self-wind using an electric motor which runs constantly, driving an eccentric. I am not sure what voltage the motor is - there is a transformer in the case, so it might not be 240v. The master provides 24v pulses once a minute to drive the slaves, which are round things which hang on the wall. Which is it that you have? If the latter, and you want to retain the movement, you'll need a 24v pulse once a minute which will drive the hands around appropriately - no winding involved. cheers Mark __________________ "The best dBs, come in 3s" - Woody Brown

25th Feb 2024, 5:48 pm	#3
osx86apple Pentode Join Date: Dec 2014 Location: Torquay, Devon, UK. Posts: 148	Re: IBM/ITR master clocks Hi Mark, Thanks for the reply. Mine are the later variant which has a mainspring vs the weight movement which I believe those were wound by a 240v motor. The type I have is similar to here http://www.hvtesla.com/masters/itr.html

25th Feb 2024, 6:27 pm	#4
Nickthedentist Dekatron Join Date: Jan 2005 Location: Oxford, UK. Posts: 17,874	Re: IBM/ITR master clocks I have one like that Yes, mine too has a CHUNKY coil which is energised once a minute (via contacts on a cam driven by the timekeeping movement) to keep the mainspring wound. These cases are huge and deep, so I'm not sure low-profile is a necessity. Do your LED transformers actually give out 24V, or are they a constant voltage output? Either way, you could rig one up with suitable current and voltage monitoring, then hold the switch contacts closed and see what current flows, and whether the voltage across the coil is near enough 24V. Obviously, suitable fusing in the finished design is essential. I bought mine for next to nothing 25 years ago and have only just got round to playing with it. Still not got as far as applying power yet though.

29th Feb 2024, 2:24 pm	#5
factory Octode Join Date: Jul 2009 Location: Cheshire, UK. Posts: 1,742	Re: IBM/ITR master clocks The power supplies for LED lighting are normally constant current driver units, not constant voltage and chosen to meet the current required by the LED(s). Also some types of LED driver are not isolated from the mains, they might not be happy with an inductive load either. David

6th Apr 2024, 2:45 pm	#6
osx86apple Pentode Join Date: Dec 2014 Location: Torquay, Devon, UK. Posts: 148	Re: IBM/ITR master clocks Sorry for the late reply’s on this, been a hectic few months. An LED transformer has seemed to have worked very well with no adverse effects, with suitable fusing to be on the safe side