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Standard Electric Standard Electric Time Co. "Slave" Clock / very basic electronics question

LCampbell

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It's been a long time since college physics and I was not sober a lot of that time, so I get bad sector errors when I try to remember electronics.

I picked up one of these slave clocks at an estate sale for almost nothing because they didn't know what it was and they couldn't make it tick etc. I bought a little circuit board off the internet that is powered by a 9V battery, took a month to ship from Europe.

The clock itself will advance if I connect the wires across as low as a 1.5V AA battery. Does the same with 9V or any combination thereof, so the coil mechanism seems to still be capable of performing its function when a pulse of electricity is delivered.

The manufacturer of this little 1.5" square board says it outputs 24VDC at 1 minute intervals, but if you have a clock that uses less, you have to install a resistor. (No, I have not done that yet).

I hooked a 9V battery up to the board, the board up to the clock wires, pushed the 'advance' button and nothing happened even though the LED was on saying the board was active and the computer recognized the board through a micro-USB.

The problem is, it only makes the pawl/lever to advance the minute hand barely quiver and certainly not enough to advance the hand one minute. It does seem to make the circuit board hot if you keep mashing the "advance" button.

So, the clock advances just fine under anything from 1.5VDC up to 18-ish when directly connected across the terminals. Just not using the little circuit board.

I don't know what the clock's original operating voltage was supposed to be, it's not marked on the mechanism or elsewhere on the clock that I can find, I just know that pretty much any small battery I can find in the house will make it advance, just not the circuit board at 24VDC output.

As I said, I didn't wire a resistor into the line yet, this is more of a "why won't the circuit board's 24V pulse make the minute hand advance when 1.5V from an AA battery will.
 

Tim Orr

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Good afternoon!

What can you tell us about this circuit board you bought from Europe? Can you post a photo of it? Can you post a photo of the instructions that came with it?

At first blush, if you can get the clock to advance with virtually any battery you put across the wires, but not with the circuit card, I might suspect that the circuit card is damaged / defective. Have you any test equipment of any kind? If you connect a voltmeter to the circuit card, what do you get if you then press the advance button? (Here a little analog meter might be better than a digital.) Does it truly output 24 volts? If you don't have a voltmeter, might you have a little flashlight bulb or even a little LED that you can connect across the circuit card's output? If you press and hold the "advance" button, is the output voltage continuous or is it momentary?

As an old boss of mine used to say, "Just for drill ... " have you tried reversing polarity of the wires from the circuit card to the clock?

That a battery works fine – but not the circuit card – is very telling. That the circuit card heats up with multiple actuations in a short time may or may not be telling. The fact that the pawl flutters a bit on actuation suggests the clock simply isn't getting the power it needs. There is also a possibility that the pulse duration from the circuit card may be too short, which could cause similar symptoms. Again, perhaps the literature supplied with the card might help.

Many of these old Standard Electric Time clocks were designed for 24 volt circuits, but by no means all of them.

Best regards, and keep us posted!

Tim Orr
 

LCampbell

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Good afternoon!

What can you tell us about this circuit board you bought from Europe? Can you post a photo of it? Can you post a photo of the instructions that came with it?

At first blush, if you can get the clock to advance with virtually any battery you put across the wires, but not with the circuit card, I might suspect that the circuit card is damaged / defective. Have you any test equipment of any kind? If you connect a voltmeter to the circuit card, what do you get if you then press the advance button? (Here a little analog meter might be better than a digital.) Does it truly output 24 volts? If you don't have a voltmeter, might you have a little flashlight bulb or even a little LED that you can connect across the circuit card's output? If you press and hold the "advance" button, is the output voltage continuous or is it momentary?

As an old boss of mine used to say, "Just for drill ... " have you tried reversing polarity of the wires from the circuit card to the clock?

That a battery works fine – but not the circuit card – is very telling. That the circuit card heats up with multiple actuations in a short time may or may not be telling. The fact that the pawl flutters a bit on actuation suggests the clock simply isn't getting the power it needs. There is also a possibility that the pulse duration from the circuit card may be too short, which could cause similar symptoms. Again, perhaps the literature supplied with the card might help.

Many of these old Standard Electric Time clocks were designed for 24 volt circuits, but by no means all of them.

Best regards, and keep us posted!

Tim Orr
Mr. Orr:

Thank you for your reply. Here's the image of what I bought although I did not buy it directly from the manufacturer but a "popular online auction site": Mine uses a 9V battery. I will try to find the necessary testing gear and report back. Meanwhile:

The instructions are:

[PRODUCT] is an easy to use battery operated master clock to drive
slave clocks used for example in institutions like factories, offices, and schools.
The device sends 24 volts voltage pulses every minute, every 30 seconds, or
every second to drive the clock. The device utilizes simple Windows software to
control the settings and fine tune the crystal.

INSTALLATION

The device has a two wire connector to attach the slave clock to the device.
Depending on the settings, unipolar or bipolar pulses are sent out every minute
or every 30 seconds to drive the clock.

Many slave clocks have three wires instead of two, to drive the solenoid of the
hour, and can be joined with one or the other of the wires. In most cases
[Product] is capable to drive also three wire slave clocks. However, it is
your responsibility to check the connection of your particular device!

ADJUSTING TIME

The time can be adjusted by pressing the push button. The device will send a
single pulse every time you press the button. If you keep the button pressed, the
device sends successive pulses at the interval of two pulse length times.

CONTROL PROGRAM

By default the device will send a bipolar pulse every minute with a pulse length
of 500 ms. If the default settings are not suitable for your slave clock, an easy to
use Windows program can be used to configure the device. The [Product] is a stand‐alone device, thus the USB
cable needs to be connected only when configuring the device. The [Product] is visible to the host computer as a human interface device,

Specifications
Input voltage 6‐12 VDC
Output voltage ± 24 V
Maximum output current 50 mA
Operating temperature 0 – 50 C
Dimensions 45 mm x 45 mm x 10 mm
Weight 30 g
Supported operating systems Windows 7 / 8 / 10

1627165584124.png
 

Tim Orr

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Good evening!

Please call me "Tim"!

My first suggestion is to lengthen the pulse length from 500 ms to at least 1000 ms (1 second), and see what happens. As the instructions say, even if you press the "advance" button, the pulse length is whatever it is set to, not continuous. It continues to send the same length of pulse, but after 2 pulse intervals (1 second) if you hold the button down. So you get: Pulse: Delay(2 Pulse Length): Pulse: Delay(2 Pulse Length): Pulse: Delay(2 Pulse Length): Pulse: Delay(2 Pulse Length): Pulse: Delay(2 Pulse Length): ... etc. when you hold the button down.

If you set the pulse too long, it will do no harm, but it will deplete the battery more quickly. So, once you get it working reliably, you start dialing back the pulse length until it's no longer reliable, then increase it again.

You won't need the "bipolar" option, I don't think. (Some English clocks require alternating polarity.) You'll want pulses at 1 minute apart. Do you have 2 or 3 wires out of the clock itself? You can follow the instructions there.

Did it come with the 8 AA battery pack as well?

Best regards!

Tim
 
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LCampbell

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Good evening!

Please call me "Tim"!

My first suggestion is to lengthen the pulse length from 500 ms to at least 1000 ms (1 second), and see what happens. As the instructions say, even if you press the "advance" button, the pulse length is whatever it is set to, not continuous contact closure. It continues to send the same length of pulse, but after 2 pulse intervals (1 second) if you hold the button down. So you get: Pulse: Delay(2 Pulse Length): Pulse: Delay(2 Pulse Length): Pulse: Delay(2 Pulse Length): Pulse: Delay(2 Pulse Length): Pulse: Delay(2 Pulse Length): ... etc. when you hold the button down.

If you have the pulse too long, it will do no harm, but it will deplete the batteries more quickly. So, once you get it working reliably, you start dialing back the pulse length until it's no longer reliable, then increase it again.

You won't need the "bipolar" option, I don't think. Some English clocks require alternating polarity. You'll want pulses at 1 minute apart. Do you have 2 or 3 wires out of the clock itself? You can follow the directions there.

Did it come with the 8 AA battery pack as well?

Best regards!

Tim
Thank you, Tim, I will try doing just that and see if it works. There are only two wires out of the clock. No, the 8 AA was extra and the 9V was standard with the board.
 

Tim Orr

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Good evening!

If you've got 24 volts at the output, then I'm betting it's the pulse length that is wrong, especially since the pawl quivers. What did you use to measure the voltage?

And I too would like to see a photo of the clock. Not having a third wire makes it easier in some respects, but signifies that there's no mechanism for synching the clock at the top of the hour.

Best regards!

Tim
 

davefr

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Have you measured the resistance of the clock's solenoid coil? 50 mA max. output current of the pulser may simply be too weak for your specific clock. (the fluttering may reflect that). Ohms law would say that your coil needs to be 480 ohms or greater given the specs of your pulser. I would try to increase the pulse per Tim's suggestion and also get an ohms reading from the clock's coil.

I know the pulser that Ken Reindel sells puts out 4 watts (ie about .170 amps at 24 VDC) and will drive a coil down to about 150 ohms.
 
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LCampbell

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Good evening!

If you've got 24 volts at the output, then I'm betting it's the pulse length that is wrong, especially since the pawl quivers. What did you use to measure the voltage?

And I too would like to see a photo of the clock. Not having a third wire makes it easier in some respects, but signifies that there's no mechanism for synching the clock at the top of the hour.

Best regards!

Tim
I just used a digital volt meter as I held the pulse button down after setting it to 5 seconds, it clearly read 24V. Once again, after a few tries, the circuit board rapidly got too hot to hold onto and I stopped testing it for the night.

Clock photos are below, no there was no master clock with it, or anything else, just what is shown, tossed in box with some other estate sale "junk" and miscellaneous stuff they didn't really know how to identify. I think I paid 10 bucks for it.

There is a little buzzer at the bottom, which also works when energized but with the exception of the red and black wires I added for testing, what is shown is what was there when I bought it.
 

LCampbell

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Have you measured the resistance of the clock's solenoid coil? 50 mA max. output current of the pulser may simply be too weak for your specific clock. (the fluttering may reflect that). Ohms law would say that your coil needs to be 480 ohms or greater given the specs of your pulser. I would try to increase the pulse per Tim's suggestion and also get an ohms reading from the clock's coil.

I know the pulser that Ken Reindel sells puts out 4 watts (ie about .170 amps at 24 VDC) and will drive a coil down to about 150 ohms.
I got some ridiculously low number like 10 ohms when I tried to measure it, which is obviously incorrect or the coil is defective. I was probably not testing it at the right points, but I know nothing about these clocks, it was just an impulse buy, if you'll pardon the pun.
 

davefr

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I got some ridiculously low number like 10 ohms when I tried to measure it, which is obviously incorrect or the coil is defective. I was probably not testing it at the right points, but I know nothing about these clocks, it was just an impulse buy, if you'll pardon the pun.
That coil sure looks like it could be 10 ohms. (Fairly large gauge wire and not very many turns.) If it is 10 ohms and 24V then it's asking for a 2.5 amp pulse to actuate.
 
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Tim Orr

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Good afternoon!

Probably a very good buy at $10! I'll bet the synchronizer cost more. Good idea to lengthen the pulse to 5 seconds to make the measurement. That's why I mentioned an analog meter earlier – at least you would have seen the needle jump. At 500 ms, it would have been probably too short to successfully measure the output voltage on a digital, unless it was a very good one. I think your learned more in your physics class than you are letting on!

I had a couple of these, and the buzzers in them worked on "doorbell" AC, or about 16 VAC. They were loud enough to wake up the neighbors!

Did you get the synchronizer to drive the clock successfully?

Best regards!

Tim
 

skruft

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A side thought might be, connect this device to the coil of a miniature 24v relay rather than the clock itself. Then you can choose whatever voltage and amperage the clock needs and send it through the relay.
 
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LCampbell

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That coil sure looks like it could be 10 ohms. (Fairly large gauge wire and not very many turns.) If it is 10 ohms and 24V then it's asking for a 2.5 amp pulse to actuate.
I tested the resistance at the two posts where the output wires would go to the clock, figuring the coil wires went to those (otherwise, what would be the point, ) and got a steady 10 ohms.
 

LCampbell

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Good afternoon!

Probably a very good buy at $10! I'll bet the synchronizer cost more. Good idea to lengthen the pulse to 5 seconds to make the measurement. That's why I mentioned an analog meter earlier – at least you would have seen the needle jump. At 500 ms, it would have been probably too short to successfully measure the output voltage on a digital, unless it was a very good one. I think your learned more in your physics class than you are letting on!

I had a couple of these, and the buzzers in them worked on "doorbell" AC, or about 16 VAC. They were loud enough to wake up the neighbors!

Did you get the synchronizer to drive the clock successfully?

Best regards!

Tim

No, nothing thus far has worked. All that happens is the synchronizer board gets very hot. This may have been one of those expensive life-lessons.

The little buzzer produces a disproportionately large and jarring sound for its size.
 

davefr

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No, nothing thus far has worked. All that happens is the synchronizer board gets very hot. This may have been one of those expensive life-lessons.

The little buzzer produces a disproportionately large and jarring sound for its size.
That means the output of the synchronizer is being overloaded by a 10 ohm load. Skruft is right. You need the synchronizer to drive a secondary circuit that can power the coil. A 24 VDC power supply and amp meter will tell you how much current the coil needs when it actuates. Ohms law would suggest about 2.4 amps.
 

LCampbell

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That means the output of the synchronizer is being overloaded by a 10 ohm load. Skruft is right. You need the synchronizer to drive a secondary circuit that can power the coil. A 24 VDC power supply and amp meter will tell you how much current the coil needs when it actuates. Ohms law would suggest about 2.4 amps.
Thank you, looks like this is a somewhat bigger project than I thought. So putting a resistor in to reduce the voltage output won't fix this, or will it? That's the manufacturer/seller's recommendation: Put a resistor in to get the voltage to where you need it.
 

davefr

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Thank you, looks like this is a somewhat bigger project than I thought. So putting a resistor in to reduce the voltage output won't fix this, or will it? That's the manufacturer/seller's recommendation: Put a resistor in to get the voltage to where you need it.
No, that will make is worse. You need the full 24 VDC but more amps. Adding a resistor will reduce the voltage AND the amps.
 

LCampbell

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No, that will make is worse. You need the full 24 VDC but more amps. Adding a resistor will reduce the voltage AND the amps.
Thank you. Looks like I shoulda done more research before I picked "most inexpensive" at the auction site. :/

Either I have some more small electronics purchases to research or put this one back in the projects box.
 

Toughtool

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It seems to me that the resistance of the coil at 10 ohms is really low and would suggest to me that there is a problem with the coil. I can't imagine a 24 volt secondary requiring 2.5 amps to operate. However I am not familiar with Standard Electric Time movements.

Even IBM's 24 volt DC program magnet, which is pretty hefty and moves a large mass, only draws 0.280 amps. That means it's coil resistance is about 85 ohms.

The reason the driver is getting hot is because it sees a near short at 24 volts. Maybe the coil voltage is closer to 2.4 volts , not 24, resulting in about 0.200 amps. I thought these movements were around 1.5 volts and wired in a series circuit. See if this web site will be of any use to you.


There you will find this:
"SERIES type clocks have a resistance of around 8 ohms and will operate alone on less than 2 volts, except in the larger sizes. A dozen or so series type clocks may be connected in series and operated from a 24 VDC master. In school installations, they would figure on allowing 2 volts per clock, to include the resistance of the interconnecting wires. In a typical collector residence installation, the interconnecting wires are much shorter, so up to around 15 series clocks may be run on 24 volts DC. The current should be in a range from 180 to 200 milliamperes and if it exceeds this, as it will with a smaller number of clocks than the optimum amount for the voltage supplied..."
and
"A single 1.5 volt "D" cell is satisfactory for running a series slave having a self-contained electronic switching-only master (one supplying no output from its own battery cells)..."
 
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davefr

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It seems to me that the resistance of the coil at 10 ohms is really low and would suggest to me that there is a problem with the coil. I can't imagine a 24 volt secondary requiring 2.5 amps to operate. However I am not familiar with Standard Electric Time movements.

Even IBM's 24 volt DC program magnet, which is pretty hefty and moves a large mass, only draws 0.280 amps. That means it's coil resistance is about 85 ohms.

The reason the driver is getting hot is because it sees a near short at 24 volts. Maybe the coil voltage is closer to 2.4 volts , not 24, resulting in about 0.200 amps. I thought these movements were around 1.5 volts and wired in a series circuit. See if this web site will be of any use to you.


There you will find this:
"SERIES type clocks have a resistance of around 8 ohms and will operate alone on less than 2 volts, except in the larger sizes. A dozen or so series type clocks may be connected in series and operated from a 24 VDC master. In school installations, they would figure on allowing 2 volts per clock, to include the resistance of the interconnecting wires. In a typical collector residence installation, the interconnecting wires are much shorter, so up to around 15 series clocks may be run on 24 volts DC. The current should be in a range from 180 to 200 milliamperes and if it exceeds this, as it will with a smaller number of clocks than the optimum amount for the voltage supplied..."
and
"A single 1.5 volt "D" cell is satisfactory for running a series slave having a self-contained electronic switching-only master (one supplying no output from its own battery cells)..."
^^^That might be the answer. The OP should try and actuate the clock with one or two D batteries and measure the amps with his meter. In any event, his 50 ma pulser won't provide the power without a secondary circuit to boost the power.
 

Toughtool

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I agree with using a D cell battery to test the coil and the OP mentions a 1.5 volt AA battery will operate the coil. This supports the 1.5-2 volt coil at 8 to 10 ohms mentioned in the web site information I posted.

The clock itself will advance if I connect the wires across as low as a 1.5V AA battery. Does the same with 9V or any combination thereof, so the coil mechanism seems to still be capable of performing its function when a pulse of electricity is delivered.
Most likely the buzzers are a 24 volt parallel circuit and the secondaries were wired in series, (at 1.5-2.0 volts each), as a one minute impulse circuit. A series resistor would in fact work to divide the voltage and limit the current to 200 mA (0.200 amps) but 200mA is four times the rated output of his driver circuit board.

"Specifications
Input voltage 6‐12 VDC
Output voltage ± 24 V
Maximum output current 50 mA"

So his circuit board driver is not going to work without a circuit following his circuit board driver/timer. He needs a driver that has a variable output voltage which will allow for a 1.5 to 2 volt output and maybe allow more than one secondary to be connected. One solution is using a DC to DC converter to convert the 24 volts to an adjustable voltage of 1.5 to 24 volts output. Something like this: Amazon.com: Valefod 6 Pack LM2596 DC to DC High Efficiency Voltage Regulator 3.0-40V to 1.5-35V Buck Converter DIY Power Supply Step Down Module: Automotive
Then adjusting it's output ti the 1.5 volts needed to drive the movement.
 
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LCampbell

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Thanks to all who have replied, it took me a couple days to get back to this. So I again measured the resistance at the terminals on the back of the clock where the wires would be attached and got a solid 9.9-10 ohms resistance.

Then, setting my voltmeter to mA, I advanced the minute hand using a 1.5V AA battery for a power source, which gave a reading of 350 mA each time I tried it (maybe 10-20 times). This fits pretty closely with the info from this source:


""Coil Electrical Properties
Inductance 390 mH, Resistance 10 Ohms, pull in current 260 ma, drop out current 30 ma. This is with a small piece of 3x5 card stock adding tension to the spring. Without adding tension the clock will not move the hands, but with the card the clock keeps time and the pull in current is about 60 ma and drop out current is 10 ma."

(I didn't use any card stock to tension the spring, etc, just took the measurements. Also, decided to go for broke, put a 9v battery on the coil and my volt meter made a rapid beeping noise and went dark when I advanced the hand.)

Thus, as many of you have said, the board I have just isn't gonna carry the mail, or in this case, the current I need without some additional mods. Might be back to just buying another commercially available product and starting again.
 

Toughtool

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Yep the 9 volt battery is way too much. I=E/R (Ohms Law). Increase E and I goes up proportionally. Increase the voltage by nine times and current will increase nine times. Since this is a DC circuit the inductance only enters the picture with the counter EMF that is generated when the circuit is closed or opened.

So, using the power formula P=E*I, 1.5 volts X 0.260amps, we get a secondary that consumes about 0.39 watts. Your pulser's maximum output is (P=E*I) 24 volts X 0.050amps, we get 1.2 watts, or three times the consumption. So if I haven't made any glaring errors in thinking here, your pulser should work with my DC to DC converter scheme. Here is a link to where I used a DC to DC boost converter to boost the voltage from 12 to 24 volts for my IBM secondaries. You would need a buck converter, a step down voltage.



Your connections would be simpler. First connect a 9, 12, or 24 volt source into the converter and adjust the output to 1.5 volts. Then connect the + and - outputs of your pulser to the + and - inputs of the DC to DC converter. Then connect the + and - outputs of the DC to DC Converter to your secondary's coil. Don't forget the Diode across the output I mentioned in the article. Done
 
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davefr

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Thanks to all who have replied, it took me a couple days to get back to this. So I again measured the resistance at the terminals on the back of the clock where the wires would be attached and got a solid 9.9-10 ohms resistance.

Then, setting my voltmeter to mA, I advanced the minute hand using a 1.5V AA battery for a power source, which gave a reading of 350 mA each time I tried it (maybe 10-20 times). This fits pretty closely with the info from this source:


""Coil Electrical Properties
Inductance 390 mH, Resistance 10 Ohms, pull in current 260 ma, drop out current 30 ma. This is with a small piece of 3x5 card stock adding tension to the spring. Without adding tension the clock will not move the hands, but with the card the clock keeps time and the pull in current is about 60 ma and drop out current is 10 ma."

(I didn't use any card stock to tension the spring, etc, just took the measurements. Also, decided to go for broke, put a 9v battery on the coil and my volt meter made a rapid beeping noise and went dark when I advanced the hand.)

Thus, as many of you have said, the board I have just isn't gonna carry the mail, or in this case, the current I need without some additional mods. Might be back to just buying another commercially available product and starting again.

My next step would be to contact Ken Reindel and see if his pulser would work. He claims it's capable of 1.5 to 25 V and it's 4 watts. At 1.5 V that would be more then enough current. He also mentions Standard Electric in the specs. I have Ken's pulser and it's been flawless.

Here's the link:
 

John Sidlauskas

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Dear Writer / Campbell,
I wish I got to this sooner! This clock is from around the 1920s. If you got this slave clock to move at 1.5v AA battery, PLEASE DO NOT USE the 24v circuit board. Not all of these used 24v. This uses for me usually around 1.5 - 2.7v to power. If you use too much voltage, u will burn the coils over time, and / or ruin the equipment such asaccelerated wear! I have many of these clocks ranging from Voltages. If you would like, I believe I know what master clock / pulser u are using. I saw them going for around 100 dollars on ebay. You have to program them first I think. I would buy a relay that uses 24vd and step down the voltage to around 3volts MAX. AC and DC - AC= Direct Current :What the house plug uses: and (DC which is Direct Current which is what this Clock uses.)
 

John Sidlauskas

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It seems to me that the resistance of the coil at 10 ohms is really low and would suggest to me that there is a problem with the coil. I can't imagine a 24 volt secondary requiring 2.5 amps to operate. However I am not familiar with Standard Electric Time movements.

Even IBM's 24 volt DC program magnet, which is pretty hefty and moves a large mass, only draws 0.280 amps. That means it's coil resistance is about 85 ohms.

The reason the driver is getting hot is because it sees a near short at 24 volts. Maybe the coil voltage is closer to 2.4 volts , not 24, resulting in about 0.200 amps. I thought these movements were around 1.5 volts and wired in a series circuit. See if this web site will be of any use to you.


There you will find this:
"SERIES type clocks have a resistance of around 8 ohms and will operate alone on less than 2 volts, except in the larger sizes. A dozen or so series type clocks may be connected in series and operated from a 24 VDC master. In school installations, they would figure on allowing 2 volts per clock, to include the resistance of the interconnecting wires. In a typical collector residence installation, the interconnecting wires are much shorter, so up to around 15 series clocks may be run on 24 volts DC. The current should be in a range from 180 to 200 milliamperes and if it exceeds this, as it will with a smaller number of clocks than the optimum amount for the voltage supplied..."
and
"A single 1.5 volt "D" cell is satisfactory for running a series slave having a self-contained electronic switching-only master (one supplying no output from its own battery cells)..."

I just realized you notioned this! As soon as I saw people saying to use 24v my mind almost blew Up hahah! EDUCATION is KEY! Its so sad that a lot of this stuff is so sparce!
 

John Sidlauskas

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Sometimes, when you are without master, the greatest solution is to get a 1RPM Syncronous motor, hook up a lever to it so as it rotates each minute, it can hit a limit switch to activate whatever you want! Simple and easy!
 

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