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  1. #1

    Default Name Of Clock With Arc Pendulum???

    Bought clock this clock and trying to research this. What is the name of these types of clocks. Also how do they work? Appreciated, thanks.
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    Popeye-Love This Forum!!!

  2. #2
    Registered User Tom Kloss's Avatar
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    Default Re: Name Of Clock With Arc Pendulum??? (RE: popeye)

    Hi Popeye

    That is an electric battery operated clock. There is a battery in the base. It is not a quartz movement it is mechanical. The swing of the pendulum drives the clock. I have one in my collection.

    T.J. Kloss
    "Find a need and fill it". Henry J. Kaiser


  3. #3

    Default Re: Name Of Clock With Arc Pendulum??? (RE: Tom Kloss)

    Any idea on age of this clock? I did not know battery operated-I thought it was old and somewhat scarce. Thanks for response!

    Quote Originally Posted by T.J. Kloss View Post
    Hi Popeye

    That is an electric battery operated clock. There is a battery in the base. It is not a quartz movement it is mechanical. The swing of the pendulum drives the clock. I have one in my collection.

    T.J. Kloss
    Popeye-Love This Forum!!!

  4. #4

    Default Re: Name Of Clock With Arc Pendulum??? (RE: popeye)

    Your clock is best known as the KundO transistor switched battery clock.

    The curved pendulum rod is plated iron and has a small ferrite permanent magnet inserted in the right end when facing the clock.

    The curved magnetic pendulum swings through a solenoid or electromagnet; a special one with two coils. One coil senses the motion of the magnetic pendulum which generates a small current. This small current "turns-on" a transistor switch. The transistor switch energizes the other coil in the solenoid which propels the pendulum.

    The movement isn't a clock....instead it is an analog counter which counts the half-swings of the pendulum and represents the count as minutes and hours on the dial. A pawl on the pendulum advances a ratchet which drives the dial motion train and hands.

    These appeared post 1958 when Leon Hatot (ATO) released his license to use the transistor switch instead of dry contacts in battery clocks. Kienenger und Obergsfeld didn't use his patent but the principle is identical.

    Curiously, the transistor on most of these KundO battery clocks is located in the plastic spool holding the coils within the brass covered solenoid.

    Other models have the transistors (2) soldered to a printed circuit board underneath the clock and the solenoid has only a single coil.

    The clocks are troublesome. The transistor is an early style with an unpredictible end-of-life. Worse, the transistor has a unique form factor and located in the coil spool and difficult to access without spoiling the brass covers. The coils are wound with thousands of turns of very fine wire and not very carefully wound. The coils are often found to be "open" due to a break in the fragile wire. This caveat does not apply to the models with the printed circuit transistors.
    H.J. (Les) Lesovsky, Alhambra California

  5. #5

    Default Re: Name Of Clock With Arc Pendulum??? (RE: Eckmill)

    Les,

    Why is this any less of a clock than a weight-driven clock with an anchor escapement, for example? The latter counts the swings of the pendulum also, representing them as minutes and hours on the dial. The only difference is the driving force that keeps the pendulum in motion. I understand why a synchronous electric "clock" isn't really a clock, since the timekeeping is entirely dependent on the frequency of the electric input. But the ATO clock's timekeeping is dependent on the period of its own pendulum.
    Jeremy

  6. #6
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    Default Re: Name Of Clock With Arc Pendulum??? (RE: Jeremy Woodoff)

    FWIW, I have the ATO version with the electronics in a PCB; I haven't overhauled it yet, but it keeps time better than a minute a week.

    The transistor itself is a germanium one, as all were then, and prone to leak. Some also develop "tin whiskers" as NASA found on their early spacecraft, but that's OT here.

    I did have one like yours quite a few years ago, and indeed had to rewind the coils, as verdigris had claimed them.

    Memory fades, but I think I put the electronics outside the coil somewhere, possibly in the base, and treated it to a silicon transistor.

    Is yours going now, Popeye?
    Mike - banned member of the throwaway society.

  7. #7

    Lightbulb Re: Name Of Clock With Arc Pendulum??? (RE: Mike Phelan)

    Jeremy Woodoff comments: "Why is this any less of a clock than a weight-driven clock with an anchor escapement..........."

    The most significant departure from a clock is that the KundO and similar do not have an escapement. All the energy driving the hands motion work comes from the inertia of the pendulum and not from a mainspring or weight.

    My statement may have been excessive but it is important to realize that a basic principle of the traditional clock involves letting the force stored in a mainspring or weight escape in carefully measured increments determined by the effect of gravity on the pendulum.

    The motion works of KundO and similar timepieces interfere with the motion of the pendulum which introduces a significant error in the rate of timekeeping.
    H.J. (Les) Lesovsky, Alhambra California

  8. #8
    Forums Administrator harold bain's Avatar
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    Default Re: Name Of Clock With Arc Pendulum??? (RE: Eckmill)

    Popeye, I am moving your thread down to the electric clock forum for better exposure.
    harold bain, Member ch 33
    "If it won't "tick",
    let me "tock" to it"

  9. #9

    Default Re: Name Of Clock With Arc Pendulum??? (RE: harold bain)

    Just picked it up. Looks to be working. Newbie to this. How can you change the time on this? Is there any way of getting instructions on this? Much appreciated, thanks.
    Popeye-Love This Forum!!!

  10. #10
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    Default Re: Name Of Clock With Arc Pendulum??? (RE: popeye)

    Change the time?? Do you mean setting the hands (just move them) or regulating (there is a thread on the pendulum bob that you turn the bob with)?
    Mike - banned member of the throwaway society.

  11. #11

    Default Re: Name Of Clock With Arc Pendulum??? (RE: Mike Phelan)

    Thanks-it was to open case and change time. I figured that out. If there is something mentioned how to set time with the pendlum I will look-it is running a little fast. Thanks for responding.
    Popeye-Love This Forum!!!

  12. #12
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    Default Re: Name Of Clock With Arc Pendulum??? (RE: popeye)

    You're welcome!
    Mike - banned member of the throwaway society.

  13. #13

    Default Re: Name Of Clock With Arc Pendulum??? (RE: Mike Phelan)

    I have one of these KundO clocks identical to Popeye's except that it has a bail handle on top. When I bought it I was attracted to the dial, but two of the brass "skirt" pieces were missing. These were easy enough to fabricate from stock hardware store brass. I never considered whether it was a true "clock" or not because I like mechanical and electromechanical devices. True, it doesn't keep time worth a flip but the one C-cell battery keeps that pendulum rocking back and forth! Not much as a static display, but curious looking when running.

    Frank in Tucker, GA

  14. #14

    Default Re: Name Of Clock With Arc Pendulum??? (RE: Eckmill)

    Quote Originally Posted by Mike Phelan View Post
    The transistor itself is a germanium one, as all were then, and prone to leak. Some also develop "tin whiskers" as NASA found on their early spacecraft, but that's OT here.
    Because these transistors were packaged in plastic, this was not ever a problem on Kundos. The germanium transistor used switches at below 1.5 volts, a silicon transistor requires too great a switch voltage to work. The break down voltage on these was 25 volts, so it is pretty immune to abuse (such as trying to connect a 9v bat to it). Kundo used two designs over the whole fo the production run years, the single transistor was licensed from ATO, the 2 transistor one (always found with a separate circuit board) was not.

    You asked for the operators manual, I have a few scans of these pages I will try and post here that show the final data sheets that were sent to consumers.
    Last edited by DC Kelley; 07-09-2009 at 12:03 PM. Reason: typo

  15. #15

    Default Re: Kundo original users manuals (RE: DC Kelley)

    Here are four pages scaned from the original Kundo users manuals
    Attached Thumbnails Attached Thumbnails hpsc1.jpg   hpsc2.jpg   hpsc4.jpg   hpsc5.jpg  

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