Magneta Master Clock Question

[Radio_Doctor]

Wasn’t sure whether to post in telephony?
I own a nice Magneta Master. Works perfectly on 4.5V via adaptor wall wart.
I want to set up 2 or 3 slaves. I have attached a photograph of the Dictograph slaves I hoped to wire in. They have 20V on the clocks? Are they suitable for connection? Any advice appreciated.
Many thanks Kneale

[Radio_Doctor]

I clearly need to understand more about this system. I have a great manual somewhere but can’t find it!

I have 2 sorts of slave clocks. Two of the Dictograph types photographed above. 20V, 295 ohms across terminals. One older type, no voltage 31.6V across terminals.

Any advice on where to start wiring these to the master appreciated.

[Robsradio]

Hi,
I don’t have one of these, so can’t provide any help, but ask a few questions.
I believe the movements were 20 v and wired in parallel. Whether the slaves were driven from the master clock contacts would be doubtful as they are only light. The contacts would have driven a relay, which in turn would run the slave circuit with 20v pulses. You mention the clock works on 4.5v, that sounds righty fit the pendulum drive coil, what voltage is stated on the rear of the pilot slave movement?
Rob

Are the Dictograph slaves unipolar or alternate polarity?

[Radio_Doctor]

Many thanks. I used a 4.5v adaptor after reading the manual I can’t find….

The pilot slave (assume meaning one in the master clock has no voltage written on it.

The dictographs have 20V, no voltage on the other older one with bevel glass front.

Not sure about the final question. Have attached photographs of the coils in case that helps?

Kneale

[Robsradio]

Looking at the photos, the first one I’m not certain whether it requires an alternate polarity pulse or uni polarity. The other two photos show a conventional uni polarity ratchet type slave, this will advance with every application and removal of power, the alternate polarity? slave would need the polarity switching every impulse for it to advance.
If you have a lab PSU just apply and remove the power and see what happens, start off with a low voltage if it’s not known what it should be.
Enjoy

[Radio_Doctor]

Many thanks for that. I incredibly don’t have a variable bench power supply but know someone who does. Job for next week I think.

I finally found the site I used when I first fitted the clock. It’s very helpful:
http://www.rogerj.co.uk/PO%2036.htm

I’ve also attached a photo of the current wiring. Looks like the dial slave is running directly off the pendulum supply.

I hope to initially run one slave. If permitted might run the other 2 into the house but that’s still under negotiation!

Thanks again for advice.

[Robsradio]

Hope you find the answers regarding the slaves when you have access to a psu. I wonder if the pilot dial had a special coil wind to suit the pendulum drive supply voltage possibly? I have a Gent PO36 but this doesn't have any dial fitted.
As for the house slaves under negotiation.... me and my wife have lived with a Synchronome master clock in the hallway and slaves in every room, you get immune to hearing them very quickly. The only time you're aware is when a visitor asks 'what's that noise?'
Let us know how you get on, but I would certainly consider driving any clocks via a relay to minimise contact loading.

[matthewhouse]

Do let us know how you get on! Master clock systems are great fun. I have 5 master clocks here. One of the Synchronomes has been clunking away every 30 seconds since I restored it nearly 3 years ago, it's currently accurate to ~5 seconds per month. It's quite mesmerising watching the mechanism, soon got used to to noise...

[Radio_Doctor]

Again many thanks. Have now worked out:
The Dictographs are unipolar and move 1 minute forward for each pulse at about 18v.
The older “ship” type clock is bipolar and goes nicely at a much lower voltage. Again moves 1 minute forward each pulse.

The Magneta master system I have pulses it’s slave dial at 30s intervals.

I am assuming these are therefore incompatible with my master clock sadly therefore?

Kneale

[valveaudio]

Hello Kneale

Why not make a small 'black box' with a simple divide by 2 circuit and a relay to produce 1 minute intervals to drive the slaves?
If you still need a bench PSU I can lend you one.

Trevor

[rambo1152]

Yes, don't give up on this just yet!

I'm sure the divide by 2 can be achieved entirely electro-magnetically, perhaps with a couple of Post Office 3000 type relays!

[Radio_Doctor]

Many thanks again,

Trevor appreciated re: PSU, have already borrowed one. The chap I borrowed it from has sold me modern pulse generator. I bought it anyway as it was cheap enough and may be handy in the future.

I would rather wire these in permanently using the master I have. If either of you were able to circuit advise I’d appreciate it. The PO relays don’t look expensive form what I can see?

Kneale

[Bob_Moss]

It might be worth getting in touch with the Museum of Timekeeping here in Notts. They've got a room full of 'em.

[McMurdo]

will anyone be editing the typo in the title?

[Radio Wrangler]

Thanks, Kevin.

David