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IBM IBM Master Clock Power Supply

JAB60

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Nov 13, 2016
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Hello. I am trying to connect a 24 volt power supply to this IBM master clock. I would assume that I could simply connect the power supply to the two wires that come off of the (and forgive me for not knowing all of the terminology) orange looking cell at the bottom of the movement.

However, the previous owner has the two wires of a power supply going to;
1) the terminal where the small red plastic shield is and 2) the terminal where is am pointing with my finger.

Are one or both of these wiring options correct? I only want to run the clock itself for time. Any information would be helpful as this is all new to me. Thanks.

SDC12008.JPG SDC12011.JPG SDC12012.JPG
 

ibm clock

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Sep 5, 2005
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First of all, does your unit have an internal transformer or rectifier? If not, then it required a seperate tranformer and rectifier. Usually, these are 24V DC, but other voltages have been made. Usually the coil is marked, or sometimes its stamped on the top of the clock.

If the coil is for DC voltage and If all you want to do is wind the master, and not run slave clocks, get this device, and simply connect it to where the two wires are that go to the coil. Model 1900W-UNV Modular Clock Winder - Ken's Clock Clinic. This device would bypass the clock contacts, as the device take cares of the timing.
 
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Edwardo

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Jun 18, 2006
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To get the clock running



Reach in to the movement with a finger

Turn the cog with the mainspring on it

This will manually wind the clock

Now swing the pendulum



To get the clock winding

From your photo this clock seems to be wired to use an external relay box

However you can still get it running as follows

Remove old supply connections

Look on the top of the clock

Connect -24v to C

Connect +24v to 1

Wire 2 to A

by doing this the clock will wind one click per minute

It would be a good idea to wire a rectifying diode across the C and A terminal with the line on the diode on the C and the other leg on the A

this will save your contacts from burning out



If you want to set up the clock to run and correct slaves

you will need to do a bit more



Let us know how you go
 

JAB60

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Nov 13, 2016
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Thank you for your responses.
IBM clock: There is no internal transformer or rectifier. All that came with the clock is what is in the pictures. No information on the coil or clock. I do have a 24 volt DC power supply.

Edwardo: I included a picture of the top of the clock. The terminals are listed as DUR, 1,2,3,4,5 and Wind. There is no C,1 or A that I see. There is a jumper between 1 and 5. The wires come into the case and then connect as in the pictures in the original post.

SDC12016.JPG SDC12017.JPG View attachment 490297 SDC12008.JPG
 

JAB60

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Nov 13, 2016
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Update:

I connected my 24 volt power supply (just a 24 volt DC cell phone / computer battery charger type device with the end cut off and two wires exposed) directly to the coil. The clock ran for a few minutes but stopped. It seemed to be struggling to push these two (one in front of movement and one inside of movement) contacts up. I took a pictures of one of the contacts (they are both the same) and where they were removed from. I believe they perhaps have something to do with the slaves (:???:). The clock has run now for an hour or so without the labouring of the extra force needed to push the contacts up. But I assume that it should not be an issue to run with these contacts in place so it seems that there is another issue. Also, it seems that the tick tock is not a strong one. A weaker beat than it should be. Just kind of getting by.


Also, the clock is ticking away with no other "once a minute" winding or adjustments being made. The coil does not engage or enable the reset lever every minute.

SDC12021.JPG SDC12022.JPG SDC12025.JPG
 

ibm clock

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Sep 5, 2005
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First of all, you cannot connect a constant voltage source directly to the coil. If you buy the clock winder that i linked to in my previous thread, you can connect that directly to the coil.

Second, the power supply needed to run this consisted of a transformer, rectifer to change the ac to dc, and a master relay. That cam you took off would make one a minute and activate the master relay which would wind the clock and advance slaves.

I doubt your cell phone charger has enough amp output to wind the clock.

But if you are going to go the cell phone charger power supply, you need to put the clock back the way the previous owner had it. Connect the power where he had it. Then when the minute impulse contacts close one a minute, the clock will wind.

But, in order to get it running, you need to wind the spring by hand, set the clock in motion, then turn your power supply one.

If you get the clock winder from the link i posted, you make it muck easier on yourself.
 

Edwardo

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Jun 18, 2006
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There are a few reasons the clock is running slowly
It could need a service / oil
or there is not enough power in the spring to run it
You will need to manually wind the spring by hand to start with
The wind coil / magnet only maintains the spring tension it doesn't wind the clock up enough for what you are doing

Put the clock back as you found it and follow the diagram I have attached
You will need to use a more suitable power supply to run this clock however if the one you have energizes the coil
you could use it for the interim for testing proposes

ibm.jpg
 

JAB60

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Nov 13, 2016
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Thank you for the responses. All of the above information helped me get the clock running strong. Edwardo, your diagram helped me a lot. Also, after you see the wiring as it should be it really starts to make sense as to how everything functions.
 

matthiasi

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Dec 3, 2010
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Sorry to Piggy-back on this thread, but feel my question is "up-the-same-alley".

So I have one of these in for repair - an IBM 25/7. It is housed in a local Post Office and the Postmaster want to have the original clock that was installed in the building up-and-running again.

I've cleaned & oiled it and am now ready to start testing it. As it controls a slave tower clock (which, in preliminary on-site testing was working) and the whole "shebang" is controlled through the control box (transformer, rectifier etc.), which I do not have, I have to dream up something else.

So my thought is to hook 2 car batteries in series, so as to get 24.5 to 26.0 Volts DC. As the clock is expecting DC voltage, this should work.

Am I wrong in my assumption and/or is there anything else I should be watching for? (Don't want to wreck it and be stuck looking for "Unobtanium", so to speak...)
 
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