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  1. #16

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

    OK, everything is wired in series with 6 volts. The gravity arm is resetting with the same force as before and the slave clock is doing nothing?? It is getting some power as the magnet barely moves, but it is not advancing.

    The adventure continues...

    Michael

  2. #17

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

    One more update for the night...

    6 volts - gravity arm works perfectly, slave clock nothing.
    7.5 volts - gravity arm works perfectly, slave clock nothing.
    9 volts - gravity arm works perfectly, slave clock nothing.

    On its own...the slave clock advances nicely at 3 volts and weakly at 1.5 volts. I am sure I am missing something simple, but that is for tomorrow. Maybe the electrical impulse is too short and the gravity arm is cutting it off before the slave has time to react

    Michael

  3. #18
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    Default Re: Correct Voltage for Gents Pulsynetic Master Clock (By: Lincolnhill)

    My Synchronome needed a bit more current to make the slave go than to make the master with its local slave operate. The only issue I can see with the variations in current we are discussing is that you may get a bit of a spark when the contacts break.

    I have a power supply with a 12 volt battery backup in my basement and I think about 29 ohms series resistance.

    Here is thepage on my synchronome it is not the same but is pretty similar to the Gents.

    [edit=19=1177987188]Fix the link color[/edit]
    Tom McIntyre Click me.
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  4. #19
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    Default Re: Correct Voltage for Gents Pulsynetic Master Clock (By: Lincolnhill)

    Michael
    Forget the resistor and the idea of running the clock from “D” cells

    “D” cells, because of their design will not last more then a few weeks

    The problem you describe indicates there is enough voltage but not enough current (AMPS)
    The batteries referred to in the manual were large lead acid batteries that could deliver many amps. (similar to car batteries).

    “D” cells can’t give the sort of service the clock needs

    If you run this type of clock off “D” cells you will find that within a week the batteries will start to fail and probably leak nasty stuff all over the place

    For what you are trying to do you don’t need the resistor to start with.
    All that it is doing is sucking more power (amps) out of the circuit

    Think of amps as the power water travels through a garden hose
    And the clock coils as empty beer cans on a wall

    If you point the hose at the empty beer cans the water blows them away
    This is because the water is coming out powerfully

    If you reduce the flow through the hose pipe by standing on it,
    the water pressure drops and there is not enough power to knock the cans off the wall

    The resister you are using is working like your foot on the pipe

    So what you need to do is turn up the pressure (amps) to get the coils to operate
    The only way to increase the Amps is to use a heaver duty power supply

    Your “D” cells can’t deliver this type of power, so after time they will self destruct

    It is not possible to burn out the coils in your clock with the type of batteries you are using
    Nor is it possible with a small 12v dc 3 amp power pack

    The worst that will happen is the coils will start to warm up if they are energised for a long period of time (30 seconds or more)

    You are more likely to destroy the batteries or supply first

    Current Diagnostic
    If the current is to low the master clock or slaves won’t work

    If the master clock works, but slave does not, the current is still to low

    If the master clock works and so does the slave, BUT the slave misses pulses or jumps on extra minutes the current is to high or very sightly to low

    You really need to invest in a power supply that is at least 1000ma (1Amp) 12vDC output

    Worry about the resistor later:-)

    Edd

    NOTE

    BTW
    Tom is correct about the spark issue
    It will eventually burn out the contacts (a few years)

    The old fix for this used resistors and capacitors. This worked very well.

    The new fix is some 2 cent rectifying diodes that can be bought from any electronic parts supplier (radio shack??)

    Simply wire one across every coil, (only one on the master clock across the terminal block on the main movement)
    Make sure that the stripe (on the diode) faces the (+) side of the circuit

    There has been a lot posted on this forum regarding the rights and wrongs of spark suppression

    I use diodes because they are cheap and they work
    They are small enough to hide behind other clock parts and do not alter the clocks originality in any way that may devalue it.

    In your case, Michael I wouldn’t worry about the diodes until you have the supply sorted

    Nice clock Tom

    [edit=4865=1178013703][/edit]
    [edit=4865=1178013744][/edit]

  5. #20

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

    Michael.
    My copy of the Chloride Gent Pul-syn-etic instruction manual is in agreement with the numbers you quoted on the 29th taken from the Gents of Leicester manual. Your calculation based on the 33 ohms electromagnet coils in the master clock and the 4 ohm coils for each slave clock is correct. It should operate on 8.14 volts (33+4 ohms times 0.22 amperes) optimally and ideally should continue to function with a source voltage as low as 6.29 volts. (37 ohms times 0.17 amperes)

    Because you state that the slave dial fails to register suggests that the slave may not be properly adjusted.

    There's other possibilities too. The electromagnet coils in the slave may have shorted turns or may have a shunt resistor in parallel with the electromagnet coil both would lower the 4 ohms resistance. (somewhat difficult to measure with an ohmmeter)

    Too, your slave might possibly be one designed to use with a Synchronome and those slaves operate at about 330 milliamperes.

    If it helps, I just tested two Pulsynetic slaves. Each operate reliably at 1.1 volts or just slightly above the 170 milliampere minimum current.

    I believe you are on the right track and it's OK to operate your Gents system from six "D" size alkaline flashlight cells arranged in series to provide just a little over 9 volts.

    Keep us posted.

    H.J. (Les) Lesovsky, Alhambra California

  6. #21

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

    Good Evening All,

    I think we are on the right track now.

    Taking Ed's advice I returned (for the fourth consecutive day, they know me by name now!) to my neighborhood Radio Shack and picked up a 12V, 1500 mA power supply. As this is more powerful than I think I needed, I connected it to the clock in series with the slave clock and two 10 ohm, 10 W resistors. The gravity arm worked perfectly, but the slave still faltered.

    So I set off to adjust the slave and low and behold after I backed the pressure off of the driving spring and off she went.

    It is now two hours later and the clock and slave have been operating perfectly and even better are within 5 seconds of my Timex. Who would have guessed that a clock that was so buggered up would have been adjusted so closely.

    As for arcing...a small flash is visible but to be honest my Standard Electric master clock that has been running flawlessly for the last eight years arcs alot more and has not needed anything other than a regular battery changing. That said, I plan on looking into a rectifying diode simply to expand my electrical knowledge a bit more. I will let you all know if it improves the arcing.

    Thank you all for your guidance. This has been a perfect example of the benefit of this message board. Hopefully I will be able to help out someone else in the future on a topic that I am knowledgable about.

    Thanks again,

    Michael

  7. #22

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

    Michael.
    Let's do the math:
    You have the 33 ohm master clock electromagnets plus the 4 ohm slave electromagnet and two ten ohm series resistors. 33+4+10+10=57 ohms
    57ohms times 0.22amperes=12.54 volts. Thus it appears that 12 volts is close to optimal.

    Now, let's hope your Radio Shack 12 volt 1.5 amp DC supply has some regulation. Typically they don't and the unloaded voltage is often much higher; 1.4 times or as high as 16 or 17 volts.

    Try inserting a milliammeter in series to measure the current with the master contacts shorted with a coin as suggested. It should not be much more than 250 milliamperes.

    Let us know.

    H.J. (Les) Lesovsky, Alhambra California

  8. #23
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    Default Re: Correct Voltage for Gents Pulsynetic Master Clock (By: Lincolnhill)

    ICKMILL

    You are correct in suggesting that the slave may not be a Gents.
    If it is a Gents, it may not be the correct type of slave for this master clock

    I would not suggest tempering with the slave movement at this stage as that could add further complications to the problem

    We are all assuming that Michael’s clock is a C7 and not a C6 or a P.O.36

    Maybe Michael can post some photos so we can confirm that we are all talking about the same thing

    The cells referred to in the Gents manual are lead acid batteries which have a different chemistry to standard “D” cells

    The main reason I do not recommend “D” cells is that they are not designed for this sort of application and will soon break down and leak.

    “D” cells are designed for a slow constant discharge not an almost short circuit every 30 seconds

  9. #24

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

    I would prefer to debate off line with Ed via eMail or by P.M. regarding the use of dry cells to provide power for the Gent pulsynetic system in a hobby-collector environment.

    Unfortunately, Ed isn't registered so Private Message isn't possible and his eMail address isn't stated so I have no choice but to defend my recommendation of the use of dry cells openly.

    I have a different view on the use of dry cells which are, in my opinion, quite satisfactory for the Gent clock used by the hobby-collector.

    True, under heavy continuous closed circuit dry cells will heat and deplete.

    However, the Gent Pulsynetic system in question consumes only 220 milliamperes for less than a tenth of a second. That occurs 120 times per hour or an accumulated duration of less than 12 seconds or a three-hundredth part of an hour.

    A standard zinc-carbon "D" size dry cell has a capacity of 150 amp-hours. One-three hundredth part of the 150 amphour capacity is a very small part of the dry cell's amp-hour capacity.

    The alkaline "D" flashlight cell is said to have a capacity of about 340 amp-hours.

    Either, I believe, in a series of six, is a completely satisfactory source for the simple Gent master clock with one slave.

    I agree that other direct current sources are entirely satisfactory and may offer special advantages but realistically, there exists few known large Gents systems in remaining in daily use which of course would be provided direct current from a supervised storage battery system.


    [edit=3=1178079945][/edit]
    H.J. (Les) Lesovsky, Alhambra California

  10. #25
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    Default Re: Correct Voltage for Gents Pulsynetic Master Clock (By: Lincolnhill)

    ECKMILL, sorry for misspelling your name in the last post

    I am not trying to debate the rights and wrongs of anything here

    Your knowledge on this forum is legendary and well respected

    I am trying to help someone out, with what I believe is the correct information

    When I did my training with Gents Chloride in London during the early1980’s, the failings of dry cell batteries were made very clear to us


    Regarding the resistance:

    Everyone is quoting 33 ohms for this master clock

    This is correct for a C7 master clock (actually between 32.4 & 35.2 in my experience)
    A C7 master clock has a built in dial and slave
    The resistance quoted is for the total unit

    A C6 is the same clock without the dial

    My C6 has two 15 ohm coils in series that make 30ohms not 33 ohms (however the real value is 29.7 ohms)

    This information is in your manual on page 2

    In the good old days Gents service techs carried around nice AVO meters to measure the current and resistants
    The problem was most of these meters were not very well calibrated

    I still have mine :-)


    This didn’t really matter as long as the clocks ran OK, after all the lead acid batteries had loads of power in reserve

    One other point, you mentioned:

    You said “I have a different view on the use of dry cells which are, in my opinion, quite satisfactory for the Gent clock used by the hobby-collector.”

    The problem is that the Gents clock was designed as an industrial machine not a hobby clock
    That’s why I recommend a more suitable power supply rather then change the batteries regularly :-)

    Don’t take this information the wrong way; I am just trying to help :-)




    BTW
    I was under the impression that I was registered and have been since last year.
    Also quite a few people have contacted me by clicking on my user name??

    I do not wish to debate this subject as your mind is already made up and I worked for Gents

    But I would be very interested in your opinion regarding an ITR clock that I have recently acquired

    I will post my questions later

    [edit=4865=1178104880][/edit]

  11. #26

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

    Here is a schema from a Gents Master clock.
    It clearly shows that all clocks are in series.

    Courtesy of Ebay U.K.

    Regards, Raymond

    Attached Thumbnails Attached Thumbnails English_MASTER_ELECTRIC_CLOCK14.jpg  

  12. #27
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    Default Re: Correct Voltage for Gents Pulsynetic Master Clock (By: Lincolnhill)

    Quote Originally Posted by RODALCO
    Here is a schema from a Gents Master clock.
    It clearly shows that all clocks are in series.

    Courtesy of Ebay U.K.

    Regards, Raymond
    Gents offered provisions for parallel connection
    The slaves were a bit different and had an advance button on them, not unlike the late model Magneta
    They ran on 24vDC to 48v DC
    The master clock had no resistor in it, but looked the same as the C6/C7

  13. #28

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

    Hello All, I have a Gents Master Clock and a seperate 9in Slave, I believe the Clock Dial inside top of Master Clock is actually a Slave. I found mine ran on a 9volt battery but was so heavy on batteries I bought a power unit to run it off the main Electricity Supply. I think I had it set at 8.5 Volts. It was so Noisy the wife threatened to leave home or set about it (The Clock) or me both with an Axe. I have it mounted on the wall in my garage and dont run it at all. In fact i have given it to my Eldest daughter and she will take it to her new home when she finishes her work tour in Germany. PS, I also have a GENTS Slave that works on alternate reverse Polarity, incompatible with mine, Anybody need one?. Regards, Ged.

  14. #29

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

    As requested, here is a photo of my now restored and running clock. Next up is to clean and wax the case.

    Thanks again for all of the help,

    Michael



    Attached Thumbnails Attached Thumbnails Pulsynetic, Gents of Leicester.jpg  

  15. #30

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

    Oops, forgot to mention that it is serial number 1481 so I believe it is pre-1930's.

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