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  1. #61
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    Now it’s getting serious. You’ve got me digging in my old boxes of transformers and “stuff” !!

    Hit the jackpot though, an old multi tapped primary toroid.

    Perfect:



    Steve

  2. #62
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    Sep 2012
    Location
    North Yorkshire UK
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    Hi Steve,

    Yep ! It works very well as long as your current (amperage) requirement is equal to or less than the transformer primary current.

    I cannot find any more info on those timers, so I suspect that it triggers something else to latch within the time period. Those plastic cases come apart quite easily, you just have to take a little care that you don't snap off the latch. If it came to the pinch a 555 timer and relay would do the same job.

    It would be interesting to see what the machine circuit looks like ! I'm curious to know why there are so many timers in there.
    Best Regards:
    Baron J.

  3. #63
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    Nov 2017
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    No sign of life when I apply power, so I think you might be in the right track with your comment earlier about the external capacitor.
    The external contact in the diagram is interesting too. Maybe it’s a trigger.

    Time to get out the wiring diagram and put all the info together.

    Steve

  4. #64
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    Nov 2017
    Location
    Geelong, Australia
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    Default The joy of having a TOS.... ( FNGJ32 mill )

    Looks like I need to link 3 & 4



    Let’s give that a try.

    Steve

  5. #65
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    Sep 2012
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    North Yorkshire UK
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    Hi Steve,

    Pins 2 and 10 are the power feed to the timer ! it should operate when you connect it across one half of the transformer.

    230 volts across the transformer.
    115 across each side.

    But you know that
    Best Regards:
    Baron J.

  6. #66
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    Sep 2012
    Location
    North Yorkshire UK
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    I think that C25 and R25 are just spike suppression components.
    Interesting that pins 3 and 4 are shorted together.
    I wonder if that graphic on the timer just illustrates internal components.
    Best Regards:
    Baron J.

  7. #67
    Join Date
    Nov 2017
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    Moving to the electrical test lab....



    With pins 3 & 4 connected it ticks like a clock. Same behavior as when fitted to the mill.

    Pulled another timer of same style.
    Power on, timer runs, clicks on.
    No ticking.

    So the original has pooped (or is repeatedly pooping) itself.

    Steve

  8. #68
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    Sep 2012
    Location
    North Yorkshire UK
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    Time to examine that internal relay !

    The contacts when closed should show a dead short.

    Is the circuit graphic the same on that other timer ?
    Best Regards:
    Baron J.

  9. #69
    Join Date
    Nov 2017
    Location
    Geelong, Australia
    Age
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    755

    Default The joy of having a TOS.... ( FNGJ32 mill )

    The other timer is actually exactly the same P/N and rating (ie 0.2-2s) - so the graphic is the same.

    I'd done a quick substitution the other night, but when you pull it out of its original position there's less "I'm alive" clunks when you turn on mains power so I thought I'd disabled something by pulling it, and didn't actually proceed test the feed.

    I checked the wiring diagram just now and the position it came out of is related to the spindle somehow, so nothing to do with the feed.
    Did the same substitution for the dodgy timer, tested the feed - clutch engages and it works fine
    Don't tell my wife I could have saved her an oil spraying if I'd gone through with the substitution test properly the other night before opening up the feed gearbox.....

    So, back to the failed timer.
    While I was testing the good timer on the bench, I tested what happens if you disconnect the trigger wire between 3 and 4 once the timer has run and energised the relay. Removing the trigger wire de-energises the relay.
    Which I'm pretty sure means there's no internal latching in the relay - so it must be held energised by the timing circuit.

    Quick sketch of the main bits:



    Powered it up again on the bench.
    Nice 22vdc out of the bridge rectifier, and its pulsing 22v at the relay input when it clicks.
    To me that fits with my theory that the timing circuit should be doing the latching.

    Steve

  10. #70
    Join Date
    Sep 2012
    Location
    North Yorkshire UK
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    Hi Steve,

    No I won't say anything. [snigger snigger]

    Sorry for the delay, wife dragged me away for dinner, I've just got back and I know that its late where you are !

    A couple of good pictures of the circuit board component side and one of the PCB will help.

    Did you check the relay contacts ? Two reasons: One you said that the clutch was only weakly working when the timer was in place and linking the contacts out caused it to operate properly. Could be caused by the short pulse from the timer. Two, I would have thought the the other contacts would have been part of the latching circuit.

    I'm only trying to rule out the relay contacts here, all the other components can be easily replaced.
    page5.png
    Best Regards:
    Baron J.

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