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  1. #61

    Default Re: Correct Voltage for Gents Pulsynetic Master Clock (By: Edwardo)

    Thanks for your reply.

    I ordered a 48V DC power supply off eBay and the clock runs a lot more happily from that, including the slave clock on the front (see photo of the movement of that here - http://www.henryandjoey.co.uk/images/SAM_0517.JPG ). It's definitely a 30-second impulse model though.

    Unfortunately, whilst the pendulum swings happily for a while and everything works as it should, it stops after a few minutes. There only seems to be about 50mA of current in the circuit when the contacts are closed, so I suspect the problem is a lack of current (even though the power supply claims to offer up to 300mA at 48V DC).

    Is it solely the weight from the gravity lever falling that provides the 'nudge' for the pendulum via the roller? I'm guessing there's something electrical involved too?

  2. #62

    Default Re: Correct Voltage for Gents Pulsynetic Master Clock (By: dw2007uk)

    dw2007uk asks: "Is it solely the weight from the gravity lever falling that provides the 'nudge' for the pendulum via the roller? I'm guessing there's something electrical involved too?"

    There's absolutely no electro-magnetic force involved in maintaining the pendulum. The electro magnets only reset the gravity arm once every fifteen cycles or 30 seconds. Thus the pendulum is free from other than gravitational forces for twenty-nine seconds.

    If there's a large wire-wound adjustable resistor in the 48 volt circuit, you should adjust the resistance so that there is a 220 milliampere current in the clocks loop. Measure the current with the pendulum stopped by shorting the contacts that cause the reset.

    Much of the circuitry and wiring in the later Gent's time transmitter clocks is to adapt the basic circuit so as to enable the use of the telephone central office battery voltage. The basic Gent and Synchronome circuits operate from two or three cells; just enough voltage to provide 220 mA to reset the gravity arm and the pilot dial plus one or no secondary or slave clocks.
    H.J. (Les) Lesovsky, Alhambra California

  3. #63
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    Default Re: Correct Voltage for Gents Pulsynetic Master Clock (By: eskmill)

    Your clock is designed to run time recorders on one minute impulses

    The circuit is split into two parts

    The main clock and pilot dial runs on a 30 second impulse but the output to the external slaves / recorders is on a one minute impulse (as per the diagram that I attached)

    The red wheel on the pilot dial opens and closes the switch above it every other impulse

    This switch is connected in series with the extra switch on the reset arm to give one impulse every other reset, (one minute) through the “recorders” circuit

    You stated that your clock is drawing 50 ma @24volts dc

    If that is the case the resistance of the circuit should be around 480ohms

    To achieve 220ma @480 ohms you would need 106 volts (which sounds incorrect)

    Also you mentioned that the resistance of your circuit is 650 ohms (sound to much to me) so something is wrong


    I think at this stage you need to start eliminating wiring problems by taking the reset coils out of circuit and measuring their resistance

    If you need guidance to do this let me know

    The reset coils together should be less then 300 ohms

    Then check the pilot dial

    You would have a heaver duty pilot coil to drive the extra contact.
    This should be around 8 ohms

    Let me know what the results are and I can give you a definite power supply specification

    You will probably need to re work the wiring to convert this clock for “domestic” use

    This is quite easy and I can talk you through it

    E

  4. #64
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    Default Re: Correct Voltage for Gents Pulsynetic Master Clock (By: Edwardo)

    Hi guys,
    I am a newbie to this site and also a new owner of a Gents master clock, first of all I would like to identify it, I can't find a serial number. can anyone tell me where to look?
    Any help would be greatly appreciated

  5. #65
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    Default Re: Correct Voltage for Gents Pulsynetic Master Clock (By: Mal 1200)

    I don't have one but from the pictures, it would be on a piece of paper
    glued to the inside left of the top of the case.
    Tinker Dwight

  6. #66
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    Default Re: Correct Voltage for Gents Pulsynetic Master Clock (By: Tinker Dwight)

    In addition (to Tinker's input) there are (at least) two numbers stamped on the case. One on the vertical portion of the top rail and one on the horizontal portion of the bottom rail. True on my 1930's model. The stampings are small and light, about 3/32"
    There's nothing obvious on my movement when in its case.
    Peter

  7. #67
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    Default Re: Correct Voltage for Gents Pulsynetic Master Clock (By: itspcb)

    Thanks for your help Tinker and Peter, there is no paper label and I'm not sure which rails you are referring to Peter, I am going to attempt to load some photos of it. Scratch that, photo files are too large to upload.

  8. #68
    Registered User Hans Vrolijk's Avatar
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    Default Re: Correct Voltage for Gents Pulsynetic Master Clock (By: Edwardo)

    [QUOTE=Edwardo;780138]Your clock is designed to run time recorders on one minute impulses

    Click image for larger version. 

Name:	Gent C7 diagram for recorders.jpg 
Views:	30 
Size:	62.7 KB 
ID:	233664
    Here's the diagram for C7 , driving recorders. As you can see the dial need a higher voltage as usual.
    Interested in my electric clocks?
    www.vrolijk-clocks.nl

  9. #69

    Default Re: Correct Voltage for Gents Pulsynetic Master Clock

    Quote Originally Posted by Edwardo View Post
    Your clock is designed to run time recorders on one minute impulses

    The circuit is split into two parts

    The main clock and pilot dial runs on a 30 second impulse but the output to the external slaves / recorders is on a one minute impulse (as per the diagram that I attached)

    The red wheel on the pilot dial opens and closes the switch above it every other impulse

    This switch is connected in series with the extra switch on the reset arm to give one impulse every other reset, (one minute) through the �recorders� circuit

    You stated that your clock is drawing 50 ma @24volts dc

    If that is the case the resistance of the circuit should be around 480ohms

    To achieve 220ma @480 ohms you would need 106 volts (which sounds incorrect)

    Also you mentioned that the resistance of your circuit is 650 ohms (sound to much to me) so something is wrong


    I think at this stage you need to start eliminating wiring problems by taking the reset coils out of circuit and measuring their resistance

    If you need guidance to do this let me know

    The reset coils together should be less then 300 ohms

    Then check the pilot dial

    You would have a heaver duty pilot coil to drive the extra contact.
    This should be around 8 ohms

    Let me know what the results are and I can give you a definite power supply specification

    You will probably need to re work the wiring to convert this clock for �domestic� use

    This is quite easy and I can talk you through it

    E
    Hi Edwardo

    My master clock ended up getting put away for a few years but I've unearthed it again!

    Do your offers of helping me measure the resistance of the reset coils and rewiring the clock for domestic use still stand? If so, I'd gladly accept!

    Thanks

  10. #70

    Default Re: Correct Voltage for Gents Pulsynetic Master Clock (By: Lincolnhill)

    Quote Originally Posted by Lincolnhill View Post
    I have just finsihed refurbishing a Gents Pulsynetic Master Clock and was wondering what the correct voltage is for this style of clock. I thought I should ask before accidentally connecting too much voltage and damaging the coils.

    In case it matters, it is a master clock with one slave dial attached.

    The only information I was able to find online said 12V to 24V but that is a pretty broad range.

    Any help would be appreciated.

    Michael
    Hi Michael..Your original question was posted over 10 years ago and attracted plenty of advice and guidance. I'm sure if you summarised what you have done since and where you are now with the clock and re-posted the pictures which seem to have gone..someone would help. Also read the other current Gents clock post which may contain relevant info.
    Perhaps even start a new thread and ask the moderator to delete your last addition to this thread (and mine !)

  11. #71

    Default Re: Correct Voltage for Gents Pulsynetic Master Clock (By: Edwardo)

    Quote Originally Posted by Edwardo View Post
    Your clock is designed to run time recorders on one minute impulses

    The circuit is split into two parts

    The main clock and pilot dial runs on a 30 second impulse but the output to the external slaves / recorders is on a one minute impulse (as per the diagram that I attached)

    The red wheel on the pilot dial opens and closes the switch above it every other impulse

    This switch is connected in series with the extra switch on the reset arm to give one impulse every other reset, (one minute) through the �recorders� circuit

    You stated that your clock is drawing 50 ma @24volts dc

    If that is the case the resistance of the circuit should be around 480ohms

    To achieve 220ma @480 ohms you would need 106 volts (which sounds incorrect)

    Also you mentioned that the resistance of your circuit is 650 ohms (sound to much to me) so something is wrong


    I think at this stage you need to start eliminating wiring problems by taking the reset coils out of circuit and measuring their resistance

    If you need guidance to do this let me know

    The reset coils together should be less then 300 ohms

    Then check the pilot dial

    You would have a heaver duty pilot coil to drive the extra contact.
    This should be around 8 ohms

    Let me know what the results are and I can give you a definite power supply specification

    You will probably need to re work the wiring to convert this clock for �domestic� use

    This is quite easy and I can talk you through it

    E
    I'm pleased to say that after its stint in storage, I finally managed to get the clock working after a bit of oiling and replacing some of the old wiring!

    When I connect a multimeter in series with the positive side of the 48V DC supply, it records 52mA (15mA of this is the pilot dial). Does this sound right? I thought it'd be more than this and yet the clock seems to be functioning well (albeit just the transmitter and its pilot dial at the moment).

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