Dust covered IBM Electric Master

Discussion in 'Electric Horology' started by markiemark, Apr 20, 2020.

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  1. markiemark

    markiemark Registered User

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    I got this at auction a few days ago, an IBM Electric Master in quite bad shape. It included a dust covered maintenance sheet, the first entry looks like 30 July 1956, all the way up to at least 23 Jan 1964. Each entry shows the level of time variation at that time - pretty cool. A schematic diagram was also included. I don't have the key to the case so will have to unscrew the back wall of the case to see what condition the movement is in. I'll post that pic once I have done that. That's all I know so far. Plan is to restore and have it running again.

    IMG_3713.JPG IMG_3714.JPG IMG_3715.JPG IMG_3716.JPG IMG_3720.JPG IMG_3722.JPG IMG_3723.JPG IMG_3724.JPG IMG_3725.JPG IMG_3726.JPG
     
  2. markiemark

    markiemark Registered User

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  3. Toughtool

    Toughtool Registered User

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    #3 Toughtool, Apr 20, 2020
    Last edited by a moderator: May 3, 2020
    This photo of an IBM master clock key that should work. I downloaded this image from this NWACC site, I think in the electric clocks forum,. You may want to find the thread and read it. It is the same key that works on my 1930 model master. Looks like you have the accumulator attachment attached to the master movement as well. This is a 12 hour auto-correction feature to correct all secondaries after a power failure. The IBM English movement shown are photos of a friend's movement I repaired after it was damaged in shipment, to the USA. Joe

    IBM MasterClockKey.jpg MasterWAccumulatorV1.jpg
     
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  4. markiemark

    markiemark Registered User

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    I'm doing a lot of research on my clock but thought I'd pose a couple of questions here which I'm trying to answer...
    1. I need to replace some of the wooden veneer. Does any know what type of timber it is?
    2. Any electrical diagrams would be helpful? Especially all the outlet terminals and what they would go too?
    3. Any instruction manuals, e.g that might describe how you set, adjust your clock such that all the slave do the same.
    4. I'd like to buy a slave clock but what what I see most have two wires. Does it only need to wires to keep time and resync with the master if the master changes?
    Cheers
     
  5. markiemark

    markiemark Registered User

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    Does anyone have a photo of a suspension spring for this clock?
     
  6. Toughtool

    Toughtool Registered User

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    1. The case looks like Oak to me, from your photos. Hard to tell. Since there are hundreds of different Oaks, you may look to a wood shop or someone who sells and installs veneer and try to get a close match.
    2. You have a late model master (1950's) so study the blueprint you have posted.
    3.You can find some information at IBM's Clock Corner at: IBM - Archives - Clock Corner - Reference Room - United States and download: https://www.ibm.com/ibm/history/exhibits/cc/pdf/cc_2407MCE1.pdf
    4. There are some commercial members here on NAWCC, and of course the web like Ebay, ect., as a source for secondaries. You want the three wire versions, ones with no second hands. You need to find out your winding magnet's voltage. one place to look is on the coil's linen wrapper. If you have a 24 volt coil, you can use 12 volt (with a resistor) or 24 volt secondaries. You may want to look at my article at: Development:“A Computer Based Master for ITR & IBM Minute Impulse Secondary Clock Movements” for more information about secondaries.
    5.If you have the ability to make a suspension spring here is a ACAD drawing and photo. https://s3-us-west-1.amazonaws.com/groupsioattachments/26282/61851618/12607/0?AWSAccessKeyId=AKIAJECNKOVMCCU3ATNQ&Expires=1587492530&Signature=5O5w92Cf/9Hq1OrHVO7ImGIarGk=&response-content-disposition=inline;+filename="ITR-IBM+Suspension.JPG"

    IBMMasterSuspension.jpg Schematic1.jpg wiring of master clk 100_0259.JPG
     
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  7. John Lippold

    John Lippold Registered User
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  8. markiemark

    markiemark Registered User

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    I have a real simple question. After studying a load of circuit schemas and documents I still don't have an answer for it. The attach photo represents the top of the cabinet. There are 9 electrical contact points. 5 labeled 1 to 5, 2 labeled Duration (A and B), and 2 not labelled (C and D).

    My questions are what are they all for. In answering that I hope to understand
    • How to connect my 24V transformer to the clock?
    • How to connect a 3 wire slave clock?
    • How to connect a 2 wire slave (if that works too). What feature do I lose with only a 2 wire slave?
    • What any remaining contact points are for?
    Thanks.

    IMG_3758.JPG
     
  9. Toughtool

    Toughtool Registered User

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    The attached schematic shows how to connect the three wire secondaries, in parallel, A to A, B to B, C to C. The C wire is the 24 volt DC line and the A and/or B lines are taken to ground to complete the circuit. Two wire secondaries do not have correction (there is an exception) and do not work with the three wire configuration because there are 80, "A" pulses per hour and only 50 (more or less) "B" pulses per hour. To run a two wire impulse secondary a separate one pulse per minute is needed. The exception is the two wire self correcting secondary. This is done by reversing the voltage of the A and C wires at the 59th minute and the use of a diode in the secondary to differentiate the two pulses. This also requires a separate circuit in the master. There is of course the two wire AC synchronous secondary [with the second hand] that I believe can be synchronized by the master with a pulse. I don't know how they work as I have no documentation.

    The duration holes, contacts, and relay, are usually used for Bells and Buzzers, as in schools. There is a cam on the master movement that can be adjusted for timing and duration.

    Schematic 3.jpg
     
  10. Toughtool

    Toughtool Registered User

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    I drew this when I was working on Jim's movement (photos I posted earlier). Hope it shows what the holes and numbers mean. I ended up rewiring his to the 1938 version of schematics.

    For the 24 volt power, I would recommend a power adapter rather than building a power supply with a transformer and bridge rectifier as shown in the schematic. I found some on Amazon between $10.00 to $20.00. I bought two that had switchable 120/240 VAC inputs.

    Jim's clock.jpg
     
  11. Toughtool

    Toughtool Registered User

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    I found this.It may help

    TopOfClock.jpg
     
  12. Toughtool

    Toughtool Registered User

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    #12 Toughtool, Apr 23, 2020
    Last edited: Apr 24, 2020
    Just so you are aware, some masters have a multi-tap transformer, rectifier, master relay, duration relay, switches and buttons, and sometimes a program unit mounted inside the master's case. Other systems using a master like mine, do not have any control parts mounted inside the master's case, except for the contacts mounted on the movement itself. These control components and power supply are mounted in a separate cabinet; connected via wires from standardized [terminals] 1,2,3,4,5,A,B,C,D, and sometimes a couple of more depending on the complexity of the installed system. As you can see in the schematic of my post #10, contacts and wiring to the left of the standardized terminals are contacts mounted on the movement inside the clock case and components to the right would be mounted in a separate cabinet.


    SI230P1.jpg
     
  13. markiemark

    markiemark Registered User

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    Hi all, thanks for all your help so far, it's been really useful. However, I have another question this time regarding the electromagnets. Both the double on the main movement and the single on the accumulator. They are both labelled 24V DC. When I put 24V DC through them nothing happens but using a multimeter I know 24V is going through them so a circuit is being made. Electromagnets are pretty simple things so my thinking is if a current is going through them they must work - but they're not! Any ideas? Could I have a current but still no magnet effect?
     
  14. markiemark

    markiemark Registered User

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    I think I resolved the electromagnet problem on one of them anyway. I actually tapped it all around lightly with a small weight just to shock it into submission! and now it works good. Maybe a loose contact somewhere inside.
     
  15. markiemark

    markiemark Registered User

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    I'm still somewhat confused about how to connect my 24VDC terminals. I think the schematics tell me to connect them to A and C but the master coil is connected to A and C so that would make a permanent circuit. There is a reference to a Master Relay and I don't know what or where I would find that. Can someone help?
     
  16. Toughtool

    Toughtool Registered User

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    #16 Toughtool, Apr 25, 2020
    Last edited: Apr 25, 2020

    I am a assuming you are referencing the schematic in Post #10. I don't know why I drew a double coil for the winding magnet, because clearly in the image of that movement from post #3, it is a single coil. I did that schematic 13 years ago. If you have a 24 volt wind coil you should see 0.132 amps (0.140 amps for the accumulator). You may very well have an intermittent open coil and may be the reason for the clocks demise. If you have to rewind the coil, you will need to count the number of turns and figure out the size of enameled wire. It is a tedious task but can be done. If you end up rewinding the coil, please keep track of the number of turns and wire size. That would be a nice tid-bit of information to know. Enameled transformer wire is still made and sold.

    The A, B, and C terminals are what is called the supervised circuit. Meaning the A signal occurs 80 times per hour and the B signal occurs 50 times an hour. A and B are taken to ground as C is always at + 24 volts. They are the lines distributed through the buildings to connect all the secondaries, and of course the power supply, wind coil, #1 terminal ect., connected as in the schematic. The wind magnet should connect to the A and C, (not using B) terminal on top of the clock and it gets wound a little, every minute and the 21 extra times during the 59th minute. If the spring is fully wound the magnet is just hitting against the stop. The clock will run fully wound on 60 pulses per hour but a power failure could cause it to run down a little and therefore may not get totally rewound, causing the clock to slow a bit.



    Since you have a master without the controls, you will need to make your own. That is what I had to do for Jim's clock. (as per the right side of the schematic in post #10) I built the controls for Jim but with smaller relays but after I bought a master with controls inside the case last year, I found the Master and Duration relays contacts were very large and mine are bad. Even though I dressed and cleaned them, I am still having a lot of trouble with them. I suggest maybe using 24 volt DC relays like this one: https://skycraftsurplus.com/24-volt-dc-relay-dpdt-25-amp-25-amp-24v-rp6055.html , It is a DPDT @ 25 amps and you will need three. IBM's original Master and Duration relays have very large contacts even though the maximum circuit current is only 2 amps. The problem is pitting from arcing. On the schematic's logic, the Run/Adv relay requires a double pole relay (DPDT) and if you use the same relay, the second pole on the Master and Stop relay contacts can be swapped down the road if or when they get burned and pitted. Remember every closing and opening of relay contacts under load will produce an arc and will vaporize a few atoms of metal every time they operate. Eventually they will fail.

    The accumulator is still a little bit of mystery to me. I didn't have it long enough to study and finding documentation on it has been tough. I did figure out that each minute the movement advances in time, the gear rotates the cam. Each impulse then moves the cam back to where it was so the net movement is zero. If it does not get the supervised impulse from A and B (no power) then the cam advances, setting up the run/advance circuit to auto correct everybody until the cam is brought back to the detent point, when power is restored.

    A comment on your question about a 2 wire impulse secondary, that requires a 1 minute pulse (60 per hour) to run. The schematic implies that the duration contact(s) closes each minute so it may be possible to use that contact for operating a plain impulse movement. Connecting to the C line and duration contact to ground on a separate pair of wires to all plain impulse secondaries.


    Remember A is taken to ground when the master relay closes on each impulse. You should connect +24 volts to terminal C and to terminal 1, which provides positive voltage to the contacts on the movement and through these contacts will power the relay coils. The C terminal will power all the secondaries. The negative (common ground) is connected to the Master relay's N/O contact and one side of each relay coil. This negative is connected to A when the master is picked and also B when the Stop relay is picked (for 50 minutes each hour).

    You may have noticed when looking at all the different schematics that there are some strange ways they connect voltages and to their circuits. Such as they will switch the primary (AC) side of the rectifier because it is easier on the contacts (less damage).

    If your wiring of the contacts on the movement is different than the schematic (left side) in post #10, I would use your wiring, if it has not been disturbed as it may be more correct.

    I hope you get this clock working and have fun doing it.
     
  17. markiemark

    markiemark Registered User

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    Thanks Toughtool, that's helping my thinking. I have a 24VDC transformer to provide the power but no master relay which I need to buy and now reading the schematic again the master relay is operated (opened/closed) by the Run/Adv-1 gate.
     
  18. Toughtool

    Toughtool Registered User

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    #18 Toughtool, Apr 25, 2020
    Last edited: Apr 25, 2020
    The master relay is connected to the minute impulse contact ( via terminal #2) through the N/C run/advanced relay. As long as the run/adv relay is not in advancing mode (not picked), the master relay will be powered once a minute for about a second though this minute impulse contact on the movement.

    When the master is in advance mode the master relay will be picked every other second by the two second contact via terminal #3.

    I have read references about not using (I think) terminal #3, if an accumulator is connected. I have not figured out what that means yet.
     
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  19. Toughtool

    Toughtool Registered User

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    #19 Toughtool, Apr 25, 2020
    Last edited: Apr 25, 2020
    You will need a minimum of three relays, a Master relay, a Run/Advance relay with two sets of contacts, and a Stop relay to make your own control. If you want a duration relay then add one more. That is the same number mentioned in the schematic of April 1, 1938, ITR Service Instruction Number 230, that I posted in post # 6. I do have permission from IBM to republish this page, which was published in the Nuts and Volts Magazine article in January 1, 2015.

    Photo is of Jims movement. It has sheared mounting pins and both frames were bent.

    Also a highly technical piece on contacts can be found here: Electrical Contacts and Contact Assemblies | Deringer-Ney, Inc. , you will find the following manual. For contact theory and design information, See Electrical Contact Design Manual . A great resource.

    Link to archived first version of article as printed. Nuts and Volts No.1 January 2015

    Page 16, I.T.R Service Instructions No 230, April 1, 1938, re-printed with permission from:
    Reference Desk
    IBM Corporate Archives
    Route 100/CSB
    Somers, NY 10589
    914-766-0612
    archive1@us.ibm.com

    Joe

    IMG_4341.jpg
     
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  20. markiemark

    markiemark Registered User

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    On the accumulator is a lever which you can move down as indicated by the red arrow.
    In it's current position there is no power. When I push the lever down it springs back up.
    When power is applied to the coil nothing happens but if I push the lever down it stays down until power is cut.
    Is that how it is supposed to work? Or, when power is applied should the lever pull itself down and stay down until power is cut?

    IMG_3787.JPG
     
  21. Toughtool

    Toughtool Registered User

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    I'm sorry but I can't help you there. I have no idea what the lever does. Maybe someone who knows about the accumulator will chime in and offer an explanation. The last time I saw an accumulator was 13 years ago and since it was not damaged on Jim's movement I didn't get a chance to study it. I believe it works similar to a secondary movement so it will stay synchronized with the master since it has the A, B, and C lines connected to it. I am very interested in the accumulator and would like to know more about it.

    I do think there is a problem with at least one set of contacts. In your first post, I noticed immediately from the photo showing mostly the accumulator, the set of contacts at the bottom look bent, or at least out of adjustment.
     
  22. markiemark

    markiemark Registered User

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    Yes, thanks. The contacts were bent but I have fixed these now.
     
  23. Toughtool

    Toughtool Registered User

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    #23 Toughtool, Apr 28, 2020
    Last edited: Apr 28, 2020
    Parts needed to build your own IBM Master clock control cabinet. Just attach wires from the terminals at the top of the clock to the terminal strip in the cabinet. 1 to 1, 2 to 2, ect. The following parts are just a suggestion.

    I am showing listing from Amazon just as a convenience. There are many other suppliers available, besides I am not familiar with Australian electronic sources or cost. You will need at least three Double Pole Double Throw (DPDT) 24 volt DC relays. These are offered 2 for $13.00 US, so if you buy four of these you will have a spare, (or have your Duration relay) @ $6.50 ea US:

    https://www.amazon.com/mxuteuk-Indicator-Electromagnetic-Aluminum%EF%BC%8C1-Warranty/dp/B07QXW1G25/ref=sr_1_4_sspa?dchild=1&keywords=DPDT+r24+volt+relay&qid=1588098260&s=industrial&sr=1-4-spons&psc=1&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUEyOVo1NUM2U1dUTkFJJmVuY3J5cHRlZElkPUEwMTAwMTYyNjA5RlNENEJFNjFZJmVuY3J5cHRlZEFkSWQ9QTA3NzE3NDdCRlc2S1hPTURENzcmd2lkZ2V0TmFtZT1zcF9tdGYmYWN0aW9uPWNsaWNrUmVkaXJlY3QmZG9Ob3RMb2dDbGljaz10cnVl

    These are plugable and have terminal screws in the base for attaching the wires. These being plugable allow swapping for diagnostic purposes. DIN Rail is a mounting method where you affix a stamped rail to a cabinet or other structure and the DIN rail supported device mounts the the rail. Wiring to the devices are usually by terminal screws making connections easy.

    Next you will need a switch. A Single Pole Single Throw (SPST) will do for the Run/ Advance switch, something like this will do:

    https://www.amazon.com/Gardner-Bender-GSW-18-Heavy-Duty-Electrical/dp/B00004WLKC/ref=sr_1_2_sspa?dchild=1&keywords=SPST+switch&qid=1588099688&s=industrial&sr=1-2-spons&psc=1&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUFUUkRIOVdSTUNRM1MmZW5jcnlwdGVkSWQ9QTAyNTcyNDIzN1AxMFhBRTZGN0xTJmVuY3J5cHRlZEFkSWQ9QTAyODI1NTkxN1FVSVhLR0w0TkdIJndpZGdldE5hbWU9c3BfYXRmJmFjdGlvbj1jbGlja1JlZGlyZWN0JmRvTm90TG9nQ2xpY2s9dHJ1ZQ==

    Here is a DIN Rail power adapter, 90-264 volts Ac to 24 Volts DC @ 5 amps. More than enough current:

    https://www.amazon.com/MEAN-
    WELL-EDR-120-24-Single-Output/dp/B00UR98FSS/ref=sr_1_21?dchild=1&keywords=240+to+24+Volt+DC+adapter&qid=1588099868&s=industrial&sr=1-21


    and here is a DIN rail terminal strip for your 1,2,3,4,5,A,B,C,D, and D terminal connections.

    https://www.amazon.com/uxcell-Double-Position-Combination-Terminal/dp/B01LYEGB9T/ref=sr_1_5?dchild=1&keywords=DIN+rail+Terminal+strip&qid=1588100180&s=electronics&sr=1-5

    Extra DIN Rail: https://www.amazon.com/15Pcs-Width-Slotted-Design-Aluminum/dp/B075MJPN28/ref=sr_1_7?dchild=1&keywords=DIN+rail&qid=1588100306&s=electronics&sr=1-7

    Just connect the parts together as in the schematic below and you have your control. Joe

    Master clock control.jpg
     
  24. markiemark

    markiemark Registered User

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    Why do I need DPDT relays? I think they're single coil to operate two independent circuits, is that right? In which case I don't see the need for that in the schematic.
     
  25. Toughtool

    Toughtool Registered User

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    #25 Toughtool, Apr 30, 2020
    Last edited: Apr 30, 2020
    Yes. Although the Master relay and the Stop relay only need one set of contacts, the Run/Advance relay needs two sets of contacts. The unused second set of the Master and Stop relays are not connected. The cost of a double pole vs single pole is about the same but there is an advantage of being able to switch relays, because they are the same, when troubleshooting a bad relay contact.

    Run/Advance set 1, switches the Master relay between one pulse per minute to a pulse every other second. The Run/Advance relay set 2 is used to pick the Stop relay during a manual advance so that the B line is connected to the A line to advance all secondaries without correction.

    Pick means energize, drop means de-energize.
     
  26. Toughtool

    Toughtool Registered User

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    #26 Toughtool, Apr 30, 2020
    Last edited: Apr 30, 2020
    In case you are willing to cheat a little, there is a plan B available. While I am a purest and try not to modify old things, I developed the electronic master out of necessity. I do not have contacts on my 1930 Mahogany cased International Time Recording master clock because it was traded in to IBM around 1950, for a clock not much unlike yours. IBM [usually] literally took an ax to the traded-in clocks to destroy them. Luckily some managers allowed employees to take them if the contacts and control components were removed and destroyed so they could not be used as masters and of course be in competition with IBM. I had over the years acquired a bunch of secondaries and had no master to run them. I even tried unsuccessfully to make something that would work and attach to to my master, but it was the gift of an Arduino that got me started on a real and accurate electronic master to run my secondaries.

    A cheaper alternative to the mechanical relay control system would be to build the ESP8266-12E NodeMCU version of the electronic master clock to control your secondaries and to wind your mechanical master clock (using A and C). Just this week (4/2020) I looked and found an ESP8266 NodeMCU for $5.82 (US) with free shipping, so add to it another $10.00 or so and you have a master that will be within a second of being on time (at the top of the hour,) for ever and ever. You can then spend all your time adjusting your IBM Master to achieve its guaranteed 10+ seconds per month accuracy using your secondaries as a reference. It is also possible to add programming and an additional MOSFET driver to operate plain impulse movements too. You can even hide the electronic master on top of the clock.

    By the way, IBM did have supervised master clocks, controlled by a master-master clock. They did this by setting the supervised master a little fast and using a mechanical lever that would drop down and contact the escapement wheel and keep it from rotating. There is enough energy in the pendulum for it to continue to swing a while but the clock did not advance until it was synchronized with he master- master, then allowed to start escaping again. Just saying.

    NodeMCU_PartA.jpg Schematic 3.jpg NodeMCU master.jpg Programming NodeMCU.jpg
     
  27. markiemark

    markiemark Registered User

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    I see, I didn't realize the Run/Advance 1 and 2 switches were run off one relay.
     
  28. Toughtool

    Toughtool Registered User

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    #28 Toughtool, May 1, 2020
    Last edited: May 1, 2020
    Figuring out relay logic can be difficult. You have to know what each relay does and when it does it. In our IBM master clock control scheme, referring to the schematic in post 10, it is important to look for notes on the schematic. Most relay schematics are drawn with relays in the de-energized position. Notice schematic notes 3,4, and 5 which mention the Stop relay. These tell you that although the schematic is drawn with the stop relay at rest, most of the time the stop relay is actually picked. Included in the schematic is a drawing of a normally closed and normally open contact set for definition; as well as a drawing of a 4PDT relay. I posted this schematic as an example of a working control for Jim's master clock which was just like yours, including an accumulator. This is Jim's master clock control and I had bought a bunch of these relays for $0.50 cents each at a Hamfest, using three of them for his clock. The drawing of the relays is included on my schematic so I would know where contact set one and two are located. Couldn't trust my memory 13 years ago either. It's even worst now.

    Here is a definition of the relays:

    1. The Master Relay's sole job is to ground the A line (and B line most of the time). Ground is the negative terminal of the 24 volt power supply and completes the circuit to energize the secondaries. It is controlled by the minute contact and the two second contact that is mounted on the master movement.

    2.The Stop Relay's job is to connect the B line to the A line for about 85 percent of each hour (50 minutes) so it is almost always picked (energized)

    3. The Run/Advance Relay' has two jobs. Contact set 1 switches the Master Relay between one minute pulses and the two second pulses. Contact set 2 is used to pick the Stop Relay if the manual Run/Advance switch is operated or if the accumulator unit needs to advance all secondaries after a power loss.

    Jim's schematic is basically the same schematic as the 1938 schematic, page 16 of the ITR Service Instruction number 230.

    Hope this helps. Joe
     
  29. markiemark

    markiemark Registered User

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    Can anyone help me understand how the accumulator works. Mine seems wired correctly. The main front wheel turns anticlockwise driven by the clock and the inner wheel turns in a counter direction at the same speed, so it looks like its sitting still. I have power to the coil to change circuit from A-B to C-B. But whether power is on or not the cam wheel never engages with any other wheel and doesn't turn. There's nothing I can see to record the time lost during a power outage so that the slaves can catch up when power is restored. I'm not sure if I'm missing a spring or some components.

    IMG_3837.JPG IMG_3838.JPG
     
  30. Toughtool

    Toughtool Registered User

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    #30 Toughtool, May 8, 2020
    Last edited: May 8, 2020
    You should have A, B, and C hooked up to the three A,B, and C terminals. I don't understand your statement about changing A-B to C-B. C will always have 24 volts on it and is never changed.

    I believe the accumulator works this way. The cam should never move more than a one minute movement unless it is out of sync (from binding, or electrical problem), or the power has been off. For every minute the master movement ticks, the master 's gear will rotate the cam one minute of rotation. Also for every minute the master ticks, the master's minute impulse contact will advance the accumulator back the same amount of motion in the opposite direction, leaving a net movement of zero and the contact at the bottom will remain in the notch in the cam. The A line goes to ground to energize the coil to advance (to move the cam back one minute) and the B grounded to energize the the coil to advance (to move the cam back 1 minute) at the top of the hour, just like a secondary. If the cam is not in synchronization then the accumulator will respond like a secondary, advance on the rapid A pulses starting at 59minutes, 10 seconds, or switch to the B (NO) contact and wait for the next B grounding at the top of the hour. If a power failure happens, there will not be a minute impulse and the cam will rotate via the gear meshed with the master movement's gear for every minute the power is out, for maximum of 12 hours. (Then it starts over because it would be in sync again) The contact at the bottom of the accumulator will close if the cam had rotated due to a power outage and this will pick the advance relay to advance (grounding A and B ) all secondaries including the accumulator when power is restored, bringing the cam back into sync again.

    If this is not how it works I hope someone can explain it. If I had one I may be able to figure it out. In the meantime I would recommend you remove and label the wires attached to the accumulator and remove the accumulator from the movement. Then you can concentrate on getting the master clock running and the control circuits built and operating at least one secondary. The accumulator unit is mounted by only two screws and the master will operate as a master with or without the accumulator attached. In other words split your problems and fix the master clock first.

    Inserted an excerpt from my article:
    Self-Regulating Operation:

    ...Starting at the top of the hour, an A and B pulse is presented, for a duration of 0.4 seconds ON, then OFF, once each minute, with the following exceptions:
    • The A signal is raised (grounded) once per minute at zero-seconds, and on every odd second between 10 and 50 during the 59th minute. Therefore the A line will get an extra 21 pulses during the 59th minute, totaling 80 pulses per hour.

    • The B signal is raised once per minute at zero-seconds for each minute except for minutes 50 to 59, where the B signal is stopped. Therefore the B pulse only occurs 50 times per hour.
    Secondaries that are late (slow) [due to mechanical or electrical failure] will receive the A pulse once per minute until the Master is at the 59th minute, then receive up to 21 rapid A pulses every other second, until late secondaries reach their 59th minute. After the 59th minute, the secondaries will switch from their Normally Closed (N/C) “A” contact to their Normally Open (N/O) “B” contact, and will only advance to the top of the hour on the next B pulse. Most secondaries will switch back to the “A” contact at four minutes after the hour, depending on the model of the secondary.

    Secondaries that are early (fast) [due to mechanical or electrical failure] will receive the A pulse once per minute until their 59th minute. Then they switch from their N/C “A” contact to their N/O “B” contact, and will ignore the A pulses while waiting for the next B pulse, before advancing.

    The next B pulse will step all the secondaries forward from their 59th minute to the top of the hour and will continue to advance the secondaries with the B pulse until the secondaries switch their cam operated contacts back to the N/C “A” contact.

    There are some early model secondaries that switch back to the B contact at 14 minutes past the hour and these are compatible with this master clock scheme since the B signal continues until 50 minutes after the hour. The service manual says, severely out of time secondaries could take up to three hours to become synchronized. Movements with more than a few minutes early or late without reason are considered in need of repair.
     
  31. markiemark

    markiemark Registered User

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    Thanks so much. It's all actually starting to make sense. I did remove the accumulator and have the master going. I'm following the wiring diagram from your Apr 24 post re: Jim's clock.

    I notice I don't have a "B" terminal at the top of my case so assume, maybe, the clock didn't originally have an accumulator. The B wire from the accumulator was hooked up to #3 terminal. But changing this as per your schematic makes it work as expected so far. I'm still learning about the accumulator.

    So now with the clock running a couple of unexpected things happened as the stop and run/adv relays opened and closed, but it might just be my understanding. There are basically 3 phases which repeat, looking at the contacts:
    (a) 10 minutes where Stop is open and Adv is open
    (b) 30 seconds where Stop is open and Adv is closed
    (c) 50 minutes where Stop is closed and Adv is open

    What is the purpose of each phase?

    I think for (c) it's the time the accumulator can use to auto advance any lost time when power is restored. But I'm not too sure.
     
  32. Toughtool

    Toughtool Registered User

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    #32 Toughtool, May 9, 2020
    Last edited: May 9, 2020
    (a) and (c) are correct. The stop relay is picked for 50 minutes per hour and released for 10 minutes.I will have to translate your phase description for (b) because you are looking at it differently than I do. So I will get back to you.

    There was a B in your hand drawing (post #8). In the schematic of post #11, I believe the A and C shown are the connections for the wind coils, so that the wind coils will get 80 pulses per hour. I have not looked at the #3 terminal connection enough to understand the reference I have seen about not connecting #3 when an accumulator is connected. I need to look at the books.

    I have looked at a blowup of your photo, of the lever, and it looks like it is an actuator to advance the accumulator's movement manually. The lever seems to be attached to the armature. In the article I mention advancing a secondary of a 562-2 by pressing the armature horizontal with your finger, then releasing, to advance the movement. It looks like it would be difficult to get your finger in there with the accumulator mounted to the master movement, so they have attached a lever to the armature so it can be accessed from the front, manually, by hand. The armature is the gray square object below the lever and it rotates CW looking at it. Therefore the lever (and the armature) should restore after it is pressed down. As with all secondary movements, the drive and check pawls are operated by gravity so the movement must be vertical and the 12:00 o'clock position must be up.

    In your case it sounds as if there is not enough magnetic energy to operate the armature with 24 volts but enough to keep it in the energized position after you press the lever down. You circuit may have a dirty A/B cam operated contact set. You can clean the contacts by pulling a strip of bond paper, soaked in 91 percent isopropyl alcohol, through a closed pair, pinching the paper, until the paper comes clean. Paper is a fine abrasive and the alcohol will remove dirt and oils. Then make sure the contacts are adjusted correctly. To test the coil, bypass the contacts and connect to the coil wires directly. Also look for binds. The contacts should be burnished (polished with a burnishing blade) if necessary. They are not usually subject to arcing because voltage is applied after they are closed or opened.

    AccAmature.jpg
     
  33. Toughtool

    Toughtool Registered User

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    Since you have the master control circuit built and the clock running, (maybe fast without the pendulum) you can connect the A,B, and C wires to the supervised circuit A,B, and C, and watch the accumulator work as a secondary. Put it it out sync manually and see if it will advance or wait, during the 59th minute as it should.
     
  34. markiemark

    markiemark Registered User

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    The accumulator seems to work and advance but it does it irrespective of the position of the advance and stop contacts. So I need to debug the wiring a bit to see what's happening. A bit more trial and error required. Cheers
     
  35. Toughtool

    Toughtool Registered User

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    #35 Toughtool, May 11, 2020
    Last edited: May 11, 2020
    I will assume you have the accumulator movement's armature working (picking and dropping) on every minute impulse and you can see the small A/B cam rotating. Notice the drive pawl will drop over the next tooth when the coil is energized (or manually operated with the lever), and will pull the gear forward (to the left) after the coil is de-energized and the armature returns to a resting position. Your photo shows the movement at about 15 minutes past the hour. If you can run the master with a short pendulum attached it will run a lot faster. It may be worthwhile to make a temporary short pendulum, maybe 1/3 as long, so you won't have to wait an hour to run through a cycle.

    What you should see is a pulse every swing of the pendulum until the A/B cam is near the top (drop point) at the cam follower. This should occur when the minute hand on the master movement is near 59 minutes. You should see the Stop relay drop at 50 minutes but no reaction on the accumulator's movement until it's 59th minute. Remember the Stop relay only connects the B wire to the A wire so they both will be grounded every impulse until the 50th minute. If the accumulator's movement is fast, the movement will stop at it's 59th minute, until the top of the hour. If the movement is slow, it will get up to 21 extra A pulses (grounds) during the 59th minute of the Master's movement.

    I suggest you disconnect the wires to the contact at the bottom of the accumulator so unexpected things will not occur. Only connect the A, B, and C terminals on the accumulator. The only time both A and B lines are active (connected) together during the 10 minute before the hour is when the master is in the Advance Mode, and there is no correction (synchronization) of any secondaries when there is an advance mode operation. The A and B lines are active (connected) for the first 50 minutes through the Stop Relay.

    BlowupMovement.jpg
     
  36. markiemark

    markiemark Registered User

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    GREAT, that was one of my outstanding questions on how that AB cam works. The accumulator is working correctly as you describe both when the master is on time and when power loss/restoration occurs. The AB cam lets the accumulator receive A pulses for 55 minutes and B pulses for 5 minutes (and never both A and B pulses). The master sends A and B pulses for 50 minutes and only A pulses for the remaining 10 minutes (49-59min). Your saying that the AB cam should change the circuit from receiving A pulses to B pulses at the 59min mark so when B pulses from the master restart on the hour so will the accumulator. I've discovered that you cannot overwind the accumulator either, by pulling repeatedly on the manual lever, so in theory so long as I'm in the 49-50min range it will sync up automatically on the hour.

    I am still bending my mind over the wiring schematic, just the manual and auto advance pieces, but need to get my questions clear in my head before asking.
     
  37. Toughtool

    Toughtool Registered User

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    Mostly Yes."A" pulses not 55 but 59 minutes. B pulses for 5, is correct starting at the top of the hour. Once the accumulator is in sync, it will always move one minute each impulse, bypassing the extra A pulses between 59 minutes and the top of the hour. You are good here. If it is late it will get one or more of the 21 A pulses. If it is early it will skip one or more A pulses.

    The accumulator does not have a windup spring There may be a slip clutch between the driven gear of the movement and what I am calling the outer cam, the one that the notch is in, the notch the contact drops into at the bottom of the accumulator. I believe the accumulator movement will continue to run in the previous setup. Advancing with each impulse and will stay in sync if there are no binds, ect. The clock secondaries work the same way. I think you are figuring it out.
     
  38. Toughtool

    Toughtool Registered User

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    I'm sorry, I should have said 60 minutes. The "A" signal occurs 60 times per hour plus the extra 21 during the 59th minute. There is always an "A" signal.

    Just for clarity, this is how my mind has reasoned the problem if time.
    1. The master clock works in seconds, the impulse secondary works in minutes. Even though my master's seconds dial shows a "60", My digital clock shows XX:00. So I count from 59 to 0 seconds, not 59 to 60 for the top of the hour.
    2. While the master stops the B signal (from 50 to 59:59, it is the secondary who decides to either ignore an A pulse or use an extra A pulse. The A pulse is always there every minute.

    I still have a problem with the International Date Line. It just seems right to me that it should change at midnight in Greenwich England instead of 12 hours later in the middle of the Pacific ocean. To make matters worse, there are a lot of countries that have their standard time 30 minutes off and a couple that use a 45 minute shift. Go figure. Unusual Time Zones
     
  39. Toughtool

    Toughtool Registered User

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    Well I really screwed this answer up. The B pulse is not for 5 minutes, it is for 50 minutes. The secondary only looks at the B pulse for 5 minutes, after it changes it's contact to the B contact. Then the secondary switches itself back to the A contact and then only looks for A pulses for the next 54 minutes. Remember the A and B lines are connected together from the top of the hour until 50 minutes after the hour.

    When the advance switch is made or the accumulator is advancing for a power loss, both A and B pulses are presented, and they are at a 2 second rate. Therefore either the A or B contact will complete the circuit and advance the movement at a rapid rate.
     
  40. markiemark

    markiemark Registered User

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    Well I think it's running correctly, just needs a bit more testing and monitoring and fine-tuning. Maybe the contacts need more cleaning too as sometimes instead on 1 clear pulse through A or B I get two very quick ones. I have too many colored wires too, black, blue gray and white so will tone that down as well.

    IMG_3860.JPG IMG_3861.JPG
     
  41. markiemark

    markiemark Registered User

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    Tough tool thanks for all your help.
    I have a question for you. In this schematic that came with the clock, the switch I've circled, I'm looking for an authentic vintage one of these from the 1950's but don't really know what I should be looking for. Obviously a hand operated switch of some description but some generic google searches aren't helping me. Is there a name for these switches so I can improve my search?

    IMG_3720 - Copy.JPG
     
  42. Toughtool

    Toughtool Registered User

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    #42 Toughtool, May 13, 2020
    Last edited: May 13, 2020
    That is the Run/Advance switch. Try searching on ITR master clock run advance switch. Also check places on ebay that have multiple clocks for sale. They may have parts available too.

    This schematic is probably your original wiring and that switch may be in a separate equipment cabinet. It is a Double Pole Double Throw switch (DPDT) where one pole switches the ground (negative) between the #4 terminal to the #5 terminal. The other pole switches master relay between terminals #2 and #3. There should be more sheets for your system because this schematic only shows the power supply with transformer connections, rectifier, master relay, and the run/adv switch. I did not see a transformer, rectifier, or switch in your clock photos. We need the rest of the schematic to see how this system was originally configured. However since you have built your own controls then this schematic is of little use other than as a historical document.

    There are many different IBM schematics, mainly because each system is designed for the unique installation of the company or school when the system was sold. My schematic of post #10 is more like the schematic of the ITR Service Instructions #230 from 1938, that has no run/adv switch. I use a Single Pole Single Throw (SPST) switch which basically picks the advance relay that does the job of your referenced DPDT switch.
     
  43. Dave Barker

    Dave Barker Registered User

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    Hi, I just finished restoring my IBM Model 35 clock. From what I understand, IBM supplied the cases in your choice of quartersawn oak or stained gumwood. Mine is gumwood, and yours appears to be gumwood from what I can see in the photos. The only veneer in the case is the back panel; the rest is solid wood. The use of gumwood in furniture and cabinet work is interesting. Gumwood is very fine grained, and was usually stained to mimic other woods. In the case of the IBM masters, there may of been an option as to the stain color. When I got mine, it was stained dark red to mimic mahogany, although the exposed surfaces had faded to lighter brown - the protected glass glazing pieces were dark red.
    Gumwood is almost unavailable these days, certainly not in any large quantities, due to it's popular use for cabinets and trim back in the earlier part of the 20th century. If you need to redo your back panel, I think you could make a new panel using birch or maple plywood stained to match the rest of the cabinet; these woods should absorb stain similar to gumwood.
     

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