Driving quartz clock motors

[oliverb]

I am building a new slave clock for my master clock (see under projects mater clock woth 7 segment dislay).

I have an old 12" dial clock case and plan to use a 30 sec clock motor for the hours and mins and 2 modified quartz clock motors for the seconds and date displays. I have enclosed a mock up picture of how the clock should look.

I have built a driver for the quartz clock motors using a 2 sec pulse from my master and a 4093 chip I had spare.

The cct works fine and has driven the quartz clock motor perfectly over the last couple of days.
I am not sure how to protect the 4093 chip from back emf from the motor coils. I would normally use reverse diodes across the motors but as the cct reverses polarity to the motors every second I don't think ths will work.

Any ideas?
Thanks.
Brett.

 

[JimB]

For your back-EMF protection, try two zener diodes in series.
Where you would normally use one diode, use two zener diodes connected in series opposition. ie connect the cathodes of the diodes together.

JimB

 

[oliverb]

Thanks for that JimB, I'll give it a go.
Brett.

 

[RODALCO]

Did you blow up a 4093 ?
In quarz clocks the IC inside usually does the lot and i doubt it that there is surge protection on the clock motor drive because it is usually low power at around 1.2 / 1.5 volts dc.
If the 4093 didn't fail over the two days you had the clock running it should be ok, but to use two 2.2 or lower value zeners back to back it may work and can't do any harm.
You can also use a led as zener. 1.7 volts for red LED's 2.2 Yellow.

 

[oliverb]

RODALCO

No I did not blow up a 4093. I am just being cautious. I remember seeing a video at work about ICs being damaged by static. The problem was that the chips were not destroyed but had their life span shortened.

I know back emf will prob not be at the same voltage levals as static but being a clock I want 24hrs operation over many years of use.

I have added the 2 zeners and the cct seems fine so I'll just leave them in.

Just got to make the new dial now. I'm using inkjet printed dry transfer paper to make my seconds and date dials. This is the first time I have used this paper but they look like they would work well on project cases and control panels etc.

Brett.

 

[Nigel Goodwin]

This is the first time I have used this paper but they look like they would work well on project cases and control panels etc.

I just print on normal paper, then laminate it - makes a nice tough front panel.

 

[kchriste]

No I did not blow up a 4093. I am just being cautious. I remember seeing a video at work about ICs being damaged by static. The problem was that the chips were not destroyed but had their life span shortened.

The 4093 is being saved by the intrinsic drain/source diodes of the output stages. These diodes clamp the voltage to the supply rails so it is good to have your supply well bypassed. Your Zeners have to be chosen so the max voltage accross them is less than Vdd + 1.4V or the EMF will still end up on the supply rails via the intrinsic drain/source diodes.

 

[RODALCO]

If it works fine it is good practise to be cautious and despike and extend the life of the driver IC.

Still don't forget that LED's work as zeners too and will give you a visual indication.

I use a Bürk masterclock at home which gives 1 minute pulses to my slave clocks which run on 24 volts.
The seconds i generate with a tacho generator which does 60 seconds in 58 real seconds.
These are used in two seconds clocks and can also be used to drive converted quartz clocks with series resistors to drop the 22.5 volts excess voltage to the clock coils.
Then it stops for 2 seconds and awaits to be released by the masterclock's minute pulse.
whole process repeats again, same as on the European railway clocks.

 

[oliverb]

I think I have seen some Bürk masterclocks on Ebay. Are they the ones with the self winding weights? I have been trying to convince my wife we need one in the dining room! The compramise is the English dial slave clock.

I have a GPO clock 36 working in my summer house. A transistor via the pendulem contacts drives a 30 sec clock for the hours and mins and GPO relays drive the seconds display. The relay operating and releasing every other second makes a fantastic tick tock sound.

I have plans in the future to move the clock 36 into the house. I will have to strip off the old orange varnish to tidy up the case. Then I want to power it from a solar panel and a lead acid battery. I have a large sealed lead acid battery I use to power my central heating when we get power cuts.

Brett.

 

[oliverb]

I just print on normal paper, then laminate it - makes a nice tough front panel.

Nigel. That's a good idea. I will not be able to use it on my clock dial but sounds ideal for front panels.
Brett.

 

[RODALCO]

Bürk masterclock

oliverb,
I bought mine on Ebay, 6 off them.

These are very quite in operation and don't clunk as the English 30 seconds clocks with the gravity weight.
Escapement is via graham dead beat escapement.
Get one with the M5 invar pendulum rod which can run at better than ± 0.4 seconds a day on a solid wall and reasonably constant temperature.

I got 4 Bürk master clocks about 2 meters away from our lounge and my wife doesn't complain so that should give you no problems for noise in your house.

Look for the ones with the 2 mercury switches on the left hand side of the mechanism, these will provide the alternating polarity one minute pulses to drive the slave clocks.
These have an inbuilt transformer 220 / 24 volts and rectifier.
Most have the 24 hour programming wheel on them as well which operates an other mercury switch which can drive an external alarm if you wish.
i use it as a pre warning for the kids to be ready for school during school days, a week switch cancells the weekends.
Every minute the fourth mercury switch, behind the dial, drives the winding motor and keeps the weight up for maximum reserve in a powercut.
after power is restored the clock adjusts all the slave dials automatically.


In German these are called Hauptuhr or Mutteruhr

Ebay Germany (Deutschland) will be the best place to get them

Some Turmuhrs are sold too but these haven't got the mercury switches and operate directly on 220 - 240 volts.

Regards from the down under

Raymond RF.

 

[wombweller]

I am building a new slave clock for my master clock (see under projects mater clock woth 7 segment dislay).

I have an old 12" dial clock case and plan to use a 30 sec clock motor for the hours and mins and 2 modified quartz clock motors for the seconds and date displays. I have enclosed a mock up picture of how the clock should look.

I have built a driver for the quartz clock motors using a 2 sec pulse from my master and a 4093 chip I had spare.

The cct works fine and has driven the quartz clock motor perfectly over the last couple of days.
I am not sure how to protect the 4093 chip from back emf from the motor coils. I would normally use reverse diodes across the motors but as the cct reverses polarity to the motors every second I don't think ths will work.

Any ideas?
Thanks.
Brett.

Hello Brett
Great use of the quartz clock.
Did you leave the quartz clock inerds all intact for this and if not what did you remove.I would like to use this but driving from the pendulum of a 1 sec clock. I will use light sensors for the trigger but how would i get the 1 sec ac that the quartz movement requires.

Regards Mark

 

[oliverb]

Hi
All the quartz clocks I have seen come apart very easy. Just disconnect the wires from the circuit board to the coil. Connect your new driver cct to the coil.

The length of pendulem gives the 1 sec swing you require. You can prob get a 1 sec pendulem from a craft shop. Or use a shorter 1/2 or 1/4 second pendulem and use a divider cct to give 1 sec.

The problem is you will need to give the pendulem a tiny kick every now and then to keep it swinging (an electro magnet). This is where it gets more complex.


You could always buy an old electric clock from ebay and use it's pendulem and drive motor.

I did this some time back here under clock 36. **broken link removed**

Hope this helps.

 

[wombweller]

Hi
All the quartz clocks I have seen come apart very easy. Just disconnect the wires from the circuit board to the coil. Connect your new driver cct to the coil.

The length of pendulem gives the 1 sec swing you require. You can prob get a 1 sec pendulem from a craft shop. Or use a shorter 1/2 or 1/4 second pendulem and use a divider cct to give 1 sec.

The problem is you will need to give the pendulem a tiny kick every now and then to keep it swinging (an electro magnet). This is where it gets more complex.


You could always buy an old electric clock from ebay and use it's pendulem and drive motor.

I did this some time back here under clock 36. **broken link removed**

Hope this helps.

Oliver

Thanks for the info.I have all the required parts regards pendulums,I have a couple of gpo 36's I also have another set up with just the pendulum swinging from the hipp/toggle with no outputs for slaves.
I was going to use a quartz movement as in your set up.

Are we removing the quartz circuit board and just keeping the coil? I have taken these appart before and used the quartz circuit for projects that required 1 sec ac pulses.
I am going to use light sensors to trigger the power to the quartz, when the pendulum passes through the beam and breaks it a pulse will be generated.

My main question was about the 4093 chip you used. I would require a 1 sec ac pulse for the modified quartz slave.How would the 4093 chip be wired to give the required pulse for my set up?


Regards Mark

 

[oliverb]

Yes the cct board can be removed or left in it's up to you.
The diagram for the 4093 is at the top of the page just arrange your light sensors to o/p a 2sec pulse. The 4093 will everse the polarity to the drive coil twice for every 2 sec pulse giving your 1 sec drive.

 

[wombweller]

Yes the cct board can be removed or left in it's up to you.
The diagram for the 4093 is at the top of the page just arrange your light sensors to o/p a 2sec pulse.

You say to o/p a 2 sec pulse, sorry I'm a little confused here .Are you saying triggered for a 2 sec period or 1 pulse every 2 secs?

The 4093 will everse the polarity to the drive coil twice for every 2 sec pulse giving your 1 sec drive.

AHHH! Did not realise that I would use the same circuit

Mark

 

[mvs sarma]

use Opto isolator to supply 50Hz pulses at say 5V and after due division it can run as a bus at TTL level. whereever you need put a resistor and Red LED in series and return to ground.
the drop acroos the LED should be suitable to your needs to drive 4093,

 

[wombweller]

I am building a new slave clock for my master clock (see under projects mater clock woth 7 segment dislay).

I have an old 12" dial clock case and plan to use a 30 sec clock motor for the hours and mins and 2 modified quartz clock motors for the seconds and date displays. I have enclosed a mock up picture of how the clock should look.

I have built a driver for the quartz clock motors using a 2 sec pulse from my master and a 4093 chip I had spare.

The cct works fine and has driven the quartz clock motor perfectly over the last couple of days.
I am not sure how to protect the 4093 chip from back emf from the motor coils. I would normally use reverse diodes across the motors but as the cct reverses polarity to the motors every second I don't think ths will work.

Any ideas?
Thanks.
Brett.

Brett

How did you get the callender from the quartz movement to run as it should?

Regards Mark

 

[RODALCO]

Gents GPO 36

oliverb

Hi, I bought a Gents GPO 36 master clock of our local auction side, Trade me a couple of weeks ago.

It is in very good condition and provides 1, 6 and 30 seconds impulses.
The timekeeping is very accurate and the noise is not bad at all.
The drive to the pendulum is via Hipp Toggle.
Mine has a 30 seconds slave dial built in as well.

I will also do some projects to get the one second impulses counted via an electronic counter and perhaps via an opto coupler.

I will keep this thread alive with results,

Kind regards, Raymond