Page 1 of 2 12 LastLast
Results 1 to 20 of 26

Thread: Clock Pendulum Needs Bigger 'PUSH'

  1. #1
    Premium Member
    Join Date
    Jan 2010
    Posts
    778
    Thanks
    290
    Thanked 172 Times in 104 Posts
    Rep Power
    167
    Reputation
    1940

    Default Clock Pendulum Needs Bigger 'PUSH'

    Hi all,
    Long time no see

    I have a grandfather clock of which the new pendulum is too heavy for the coil to oscillate it into a bigger swing.

    It's swinging about one third of what it should, with the big brass looking circle plate even pushed up the poles (Increasing center of gravity). The plate should be further down - decreasing the center of gravity (greater mass) - if I have that right

    Is it possible for me to increase the push/pulse output of the coil?

    Ceramic Cap is a 104
    Electro is 47uf
    The IC is a STC 945 G C4

    Would I be right in saying that the IC is doing the cyclic pulsing?





    Thanks people.
    GT250



Look Here ->
  • #2
    Premium Member
    hinekadon's Avatar
    Join Date
    Jan 2017
    Location
    above ground level
    Posts
    215
    Thanks
    107
    Thanked 178 Times in 70 Posts
    Rep Power
    97
    Reputation
    3570

    Default

    lengthen to slow shorten to speed up on pendulum ! lighten the pendulum if you play with the timing of the magnetics it will slow down as you shorten the attraction time ????? careful now

  • The Following User Says Thank You to hinekadon For This Useful Post:

    GT250 (12-07-18)

  • #3
    Senior Member

    Join Date
    Dec 2011
    Location
    Tasmania
    Posts
    593
    Thanks
    778
    Thanked 493 Times in 248 Posts
    Rep Power
    280
    Reputation
    9061

    Default

    I’m no expert in this, but I’d first concentrate on getting the length of the pendulum spot on. From my experience with these things, the magnetic pulses are minute and it relies on the pendulum “resonating”at exactly the right frequency for it to work and gradually build up to swinging the full distance.

  • The Following User Says Thank You to shred For This Useful Post:

    GT250 (12-07-18)

  • #4
    Senior Member
    nomeat's Avatar
    Join Date
    Jan 2008
    Location
    Commonly found in a pantry or the bottom of a fridge, searching for grains, fermented or distilled
    Posts
    3,982
    Thanks
    1,044
    Thanked 1,827 Times in 1,122 Posts
    Rep Power
    860
    Reputation
    30038

    Default

    Quick 1x1 about pendulums :
    It timing depends on it's LENGTH !
    and for now that is all you need to worry about.

    There is no significant timing going on in that assistance circuit, there is no magical IC, just a plain old transistor, that needs to deliver the right amount of energy for the pendulum.
    It knows when at the moment the little magnet (that hopefully is still on the pendulum) passes the coil, then just gives it a shove.

    You want more umpf, the just power it with two AA batteries. Other ways would be larger coil and/or stronger magnet and getting the magnet as close as possible to the coil.

    Reducing the pendulum's weight would help but may not be always be an option for asthetic reasons. This would actually also have a shift of the COG becuase the arm has it's own weight (slightly reducing the length) but the position of the weight is generally adjustable.
    You woud probably need to halve the weight to make it noticable for the circuit.
    Last edited by nomeat; 11-07-18 at 07:06 PM.
    $$$...Welcome to Australia where corruption is legalized...$$$

    The only group that does not have a lobby is the middle income taxpayer.

  • The Following 2 Users Say Thank You to nomeat For This Useful Post:

    GT250 (12-07-18),tristen (11-07-18)

  • #5
    Premium Member
    hinekadon's Avatar
    Join Date
    Jan 2017
    Location
    above ground level
    Posts
    215
    Thanks
    107
    Thanked 178 Times in 70 Posts
    Rep Power
    97
    Reputation
    3570

    Default

    it could be that if you have replaced the pendulum it hasnt got its little magnet on it good luck

  • The Following User Says Thank You to hinekadon For This Useful Post:

    GT250 (12-07-18)

  • #6
    Senior Member
    nomeat's Avatar
    Join Date
    Jan 2008
    Location
    Commonly found in a pantry or the bottom of a fridge, searching for grains, fermented or distilled
    Posts
    3,982
    Thanks
    1,044
    Thanked 1,827 Times in 1,122 Posts
    Rep Power
    860
    Reputation
    30038

    Default

    Just want to add that there are also pendulum QUARZ clocks. I installed a couple of these movements in old clocks where the original electromechanical movements were corroded beyond repair.
    They were only $8 on ebay back then and they are quite powerfull and very long lasting on a single AA. I have had them for over 5 years, replaced battery two times.
    The pendulum is activated with a coil and magnet like your circuit and is only for show, so it can swing any way it likes.
    The actual clock movemenent is a pulse motor driven with a quarz circuit like standard clocks.
    One of them pushes a 50cm arm with a 20cm dia. copper weight. A lot of air friction going on there. The advantage: no ticking noise as the huge concave face of this copper clock also amplified it.

    Found the ones I used, but maybe it was $18 not $8 back then, (memory fading)
    Last edited by nomeat; 11-07-18 at 09:28 PM.
    $$$...Welcome to Australia where corruption is legalized...$$$

    The only group that does not have a lobby is the middle income taxpayer.

  • The Following 3 Users Say Thank You to nomeat For This Useful Post:

    GT250 (12-07-18),tristen (11-07-18),TVguy (17-07-18)

  • #7
    Senior Member joezep's Avatar
    Join Date
    Jan 2008
    Location
    SE Melbourne
    Posts
    821
    Thanks
    424
    Thanked 222 Times in 154 Posts
    Rep Power
    201
    Reputation
    2288

    Default

    This site is from USA that sell spare parts and has some informative videos.


  • The Following User Says Thank You to joezep For This Useful Post:

    GT250 (12-07-18)

  • #8
    Premium Member
    Join Date
    Jan 2010
    Posts
    778
    Thanks
    290
    Thanked 172 Times in 104 Posts
    Rep Power
    167
    Reputation
    1940

    Default

    First of all, thank you to everyone for your thoughts and input.
    So I'll address the replies in order

    BTW: I did say the 'new' pendulum. The original one was grabbed by a 3yr old and the ensuing damage is the after effect
    I managed after about 2 months found a broken clock with a pendulum.

    After reading all your comments, I apologise that I didn't mention that this particular grandfather clock has 3 (Three), different mechanisms each with its own battery supply.
    1) The Chime sound.
    2) The Clock Movement.
    3) The Swing Pendulum.

    The wonderful thing and a bit bizarre (and the only reason it's in the house!), is that the chime stops sounding at 10:00pm and restarts sounding at 6:00am

    Hinekadon - The 'new second hand' pendulum has a 15cm disc and the rod-faux pau brass arm is about 70cm to the end. I've had the disc all the way up as far as it will go. At the lowest, the arm hardly swings. The magnet is there. There's also no way to reduce the distance, as it's near down to 1-2mm.


    Shred - you are correct. I wonder if the pulse just sends the magnet one way and then relies on the timing to 'hit' it on its way back as in not pulsing it on its way to the other side as well...

    Nomeat - As ever the wise one! Yes you're spot on and as I've said I can't play with the length anymore (without getting the metal cutters out), and with the height of the clock having a shorter pendulum it would look really weird...
    So maybe adding another AA in series (so 3v?), won't damage the PCB?

    Your post a few hours later is probably what I have (a quartz setup). And no ticking! I hate ticking! Have changed every clock in the house to no ticking...

    Joezep - Thanks for the link.

    I guess I was naively thinking that changing either caps would give it more umph.


    Regards,
    GT250

  • The Following 2 Users Say Thank You to GT250 For This Useful Post:

    hinekadon (12-07-18),nomeat (12-07-18)

  • #9
    Senior Member
    nomeat's Avatar
    Join Date
    Jan 2008
    Location
    Commonly found in a pantry or the bottom of a fridge, searching for grains, fermented or distilled
    Posts
    3,982
    Thanks
    1,044
    Thanked 1,827 Times in 1,122 Posts
    Rep Power
    860
    Reputation
    30038

    Default

    Quote Originally Posted by GT250 View Post
    So maybe adding another AA in series (so 3v?), won't damage the PCB?
    Go for it

    It is a general purpose transistor with 40V for Vce and 5V for Veb. The voltage on the coil may be higher than 1.5V but not 40V and you could always replace it with a general purpose transistor with 80Vce or higher. If it fails I will send you some transistors
    I have seen similar circuits run on a 9V battery.
    I can't see the voltage rating for that black cap but I have never seen lower than 6.3V for that type.
    Last edited by nomeat; 12-07-18 at 10:03 PM.
    $$$...Welcome to Australia where corruption is legalized...$$$

    The only group that does not have a lobby is the middle income taxpayer.

  • The Following 2 Users Say Thank You to nomeat For This Useful Post:

    GT250 (13-07-18),hinekadon (12-07-18)

  • #10
    Premium Member
    hinekadon's Avatar
    Join Date
    Jan 2017
    Location
    above ground level
    Posts
    215
    Thanks
    107
    Thanked 178 Times in 70 Posts
    Rep Power
    97
    Reputation
    3570

    Default

    concur with nomeat jacrap have 2xaa holders

  • The Following User Says Thank You to hinekadon For This Useful Post:

    GT250 (15-07-18)

  • #11
    LSemmens
    lsemmens's Avatar
    Join Date
    Dec 2011
    Location
    Rural South OZ
    Posts
    6,864
    Thanks
    5,696
    Thanked 3,649 Times in 1,857 Posts
    Rep Power
    1592
    Reputation
    64240

    Default

    Since the pendulum is not needed for timing, could you not just take to the back of the pendulum (i.e. the bit you don't see) and lighten it a bit with a dremmel, grinder, or the like?
    I'm out of my mind, but feel free to leave a message...

  • The Following User Says Thank You to lsemmens For This Useful Post:

    GT250 (15-07-18)

  • #12
    Senior Member

    Join Date
    Feb 2008
    Location
    Mid North Coast NSW . Australia
    Age
    61
    Posts
    1,784
    Thanks
    975
    Thanked 318 Times in 214 Posts
    Rep Power
    271
    Reputation
    4277

    Default

    I've got a stack of pendulum clocks as I'm a bit of a collector of them.
    They are mostly mechanical, yet there is one electric in my kitchen, a 2' wall clock with pendulum and I've never been able to get the pendulum to swing on it.
    I've been through the cap and transistor changes, lightening the pendulum, setting distances, changing batteries, everything but the best it will do is : when it's first hung on the wall (been disturbed) it will swing for 10 secs and you can tell the circuit is pushing it then it just stops. Like as if the coil stays saturated.
    I gave up.
    Last edited by loopyloo; 13-07-18 at 08:43 PM.

  • The Following User Says Thank You to loopyloo For This Useful Post:

    GT250 (15-07-18)

  • #13
    Premium Member
    hinekadon's Avatar
    Join Date
    Jan 2017
    Location
    above ground level
    Posts
    215
    Thanks
    107
    Thanked 178 Times in 70 Posts
    Rep Power
    97
    Reputation
    3570

    Default

    is it an older type as the little magnets loose there grunt

  • #14
    Premium Member
    Join Date
    Jan 2010
    Posts
    778
    Thanks
    290
    Thanked 172 Times in 104 Posts
    Rep Power
    167
    Reputation
    1940

    Default

    I managed to make the voltage 3v and it certainly makes the magnetic 'device' swing more. Nomeat: The cap is 10v (should have mentioned that in my OP).

    So I put the arm with big disc on at it's correct length and the bugger swings at first, then comes to a halt!! Just like Loopyloo's !!!

    When I get back, I'll see if the magnetic 'part' will swing away without any weight. Maybe the weight is causing the plastic housing to bend ever so slightly and there's some friction?
    Bugger...!

  • #15
    Senior Member

    Join Date
    Apr 2012
    Location
    14 Wombat Cres, Goanna Heights NSW
    Posts
    1,150
    Thanks
    579
    Thanked 896 Times in 459 Posts
    Rep Power
    423
    Reputation
    15483

    Default

    This is almost off topic but I've been wondering... given the minuscule forces involved, does it make any difference if the pendulum movement is aligned locally with either the Earth's rotation (parallel with the equator) or the Earth's magnetic field lines (aligned north-south)?

  • The Following User Says Thank You to Bigfella237 For This Useful Post:

    GT250 (17-07-18)

  • #16
    Premium Member
    hinekadon's Avatar
    Join Date
    Jan 2017
    Location
    above ground level
    Posts
    215
    Thanks
    107
    Thanked 178 Times in 70 Posts
    Rep Power
    97
    Reputation
    3570

    Default

    the cap is for the decay of the field

  • The Following User Says Thank You to hinekadon For This Useful Post:

    GT250 (17-07-18)

  • #17
    Senior Member

    Join Date
    Feb 2008
    Location
    Mid North Coast NSW . Australia
    Age
    61
    Posts
    1,784
    Thanks
    975
    Thanked 318 Times in 214 Posts
    Rep Power
    271
    Reputation
    4277

    Default

    Quote Originally Posted by hinekadon View Post
    the cap is for the decay of the field
    Doesn't the cap discharge into the coil to drive the pendulum ?
    What's the circuit look like ?

  • The Following User Says Thank You to loopyloo For This Useful Post:

    GT250 (17-07-18)

  • #18
    Premium Member
    hinekadon's Avatar
    Join Date
    Jan 2017
    Location
    above ground level
    Posts
    215
    Thanks
    107
    Thanked 178 Times in 70 Posts
    Rep Power
    97
    Reputation
    3570

    Default dumbguy

    cant draw the circuit for you but the transister pulses and with cap it discharges slower than with out it so it holds the mag flux for a longer period if you have a long duration ( timebase) oscillorscope you can see the oscillations they are timed charge/discharge to match the pendulums actual natural rythm any over mag will slow the pend ,any to fast will increase mag and the hang time is worked to assist in a minor way to maintain this rythm . hope your lost now lol?????/don
    Last edited by hinekadon; 15-07-18 at 12:44 PM. Reason: spelling

  • The Following User Says Thank You to hinekadon For This Useful Post:

    GT250 (17-07-18)

  • #19
    Premium Member
    hinekadon's Avatar
    Join Date
    Jan 2017
    Location
    above ground level
    Posts
    215
    Thanks
    107
    Thanked 178 Times in 70 Posts
    Rep Power
    97
    Reputation
    3570

    Default

    ps the time base is worked out by the 47uf and the resistor
    Last edited by hinekadon; 15-07-18 at 12:48 PM. Reason: spelling

  • The Following User Says Thank You to hinekadon For This Useful Post:

    GT250 (17-07-18)

  • #20
    LSemmens
    lsemmens's Avatar
    Join Date
    Dec 2011
    Location
    Rural South OZ
    Posts
    6,864
    Thanks
    5,696
    Thanked 3,649 Times in 1,857 Posts
    Rep Power
    1592
    Reputation
    64240

    Default

    increase the size of the cap?
    I'm out of my mind, but feel free to leave a message...

  • The Following User Says Thank You to lsemmens For This Useful Post:

    GT250 (17-07-18)

  • Page 1 of 2 12 LastLast

    Bookmarks

    Posting Permissions

    • You may not post new threads
    • You may not post replies
    • You may not post attachments
    • You may not edit your posts
    •