Burk Electric clock with Pendulum

[Sean Williams]

Morning all,

I recently purchased a Burk clock, that is both electric and pendulum.

i will show my complete ignorance in these matters, and say I do not see how this works.

The clock is dual voltage (110 and 220) so I think I need to wire both of the clock motor coils in series.

I am wondering what the purpose of the motor is, if there is a pendulum as well, surely if the motor drives the clock, then the prndulum is a little redundant?

Any help or advice gratefully received

Cheers
Sean

[Station X]

Does it actually have a motor Sean?

Some electric pendulum clocks use electromagnets to periodically attract the pendulum and maintain its swing.

[Sean Williams]

Yes, it has a small shaded pole type motor

[Station X]

In that case it'll be no different to a weight driven pendulum clock, except that its driven by a motor rather than gravity.

[broadgage]

Weight driven and spring driven clocks were manufactured that used an electric motor controlled by limit switches, to wind up the weight or spring.

The merit of this system was that the clock would continue to run during a power failure, And that timekeeping was not reliant on the mains frequency, or even on the supply being AC.

Although domestic sized clocks working on this principle were made, it was more commonly applied to large external clocks on public buildings.
The weight to be wound up for a large clock could be half a ton or so, an irksome task for hand-winding.

[Sean Williams]

Ah, studying the mechanism makes more sense now, the motor winds the mainspring, this then drives the pendulum movement, which uses the swinging weight to regulate the speed of the spring unwinding.

Having studied the motor closer the correct method of connecting the two windings means I am now happy to leave the motor to run for a bit to charge the spring.

It is a very clever bit of engineering, with a mechanical brake on the motor to stop rotation once the mainspring is wound.

[M0FYA Andy]

Sean,
Is your Burk a Master clock, providing electrical impulses at 30 seconds or, more likely, 1 minute intervals to drive slave dials?
Contrary to the English manufacturers of such clocks, such as Synchronome or Gents, who tended to go for electrically-reset gravity-arm mechanisms, the European, Scandinavian and US manufacturers used electrically-rewound conventional clock movements. They usually have a cunning mechanism to automatically advance the slaves after a short-term power outage, whereas the English systems were normally battery-powered with a float-charger.

Andy

[Sean Williams]

No, it certainly isn't a master clock, I will put a picture up later.

It has a pair of signal contacts actuated by a mercury switch though that can be triggered by pins that press in around a 24H rotating wheel.

It dated from the 1960s and is very Germanic in styling.

It is ticking away merrily now

[M0FYA Andy]

Sean,

Is it anything like this one? http://www.hvtesla.com/masters/burk.html

Andy

[Sean Williams]

Hi Andy,

Very similar, but just a straight forward clock, visually amost identical though.

[8 Tracker]

Nice find, Sean. I'm sure you know, but these would have been used in schools, factories or any building where a regular time signal was needed (school bells etc.) The pin in the wheel would actuate a contact. The mercury switch was needed to act as a timer to give a 2 or 3 second output to the bells as the pin would produce far too long an output on its' own as it slowly moved past the contacts.
I have a Gents C69, which is just the timer part on its own. It needs to be driven by a master. They are quite interesting things to watch. The mercury switch tilts every 5 minutes, but is wired in series with the contacts operated by the pins. Is yours similar or is the mercury switch operated by the pins directly?

Mark.

[Sean Williams]

I've not worked out just how the Mercury switch operates, it seems to be triggered by a quite coarse gear on the hour hand drive, there are three levers that are activated by the pin sets on the day indicator, the alarm wheel has no drive pins fitted, si is difficult to trigger.

Will do some more research when time permits