Overload trip

If you could mount the motor so that it is able to pivot - like the dynamos and alternators on cars - you could use a spring to hold the motor on one side of the slack, with a switch to turn off the input if the motor moved to the stalled side. You would need to adjust the spring tension so that in the stall condition, as the motor tries to haul itself towards the driven side, the stalled movement always operates the switch. Use a switch that turns off and stays off (not a microswitch) to avoid any tendency for the motor and spring to bounce to and fro when stalled.

Not the best explanation I have offered, but I hope you see what I mean.

Regards, Tim

In the absence of a picture of Stephen's mechanism ... this might be a useful reference: **LINK**

https://www.bonhams.com/auctions/18836/lot/286/

[ ignore the green movement, that's not a Wilding clock ]

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I would like, if I may, to expand a little on yesterday's suggestion:

My thinking is that a 'missing pulse detector' would be the optimum solution.

The logic would be very simple:

• IF the Mercury Switch is closed AND the pulse train is active THEN all is well, so allow it to continue.
• IF the Mercury Switch is closed AND the pulse train is NOT active THEN there is a jam, so isolate the motor.

The pulse generator could sense motor rotation, chain movement, or wheel rotation [etc.] according to taste.

MichaelG.

Edited By Michael Gilligan on 09/02/2019 13:20:48

You overlooking the even faster fuses. They have three legs. We usually call them transistors.

Isn't that kind of comment called a 'low blow' . Groan.

I should be on the stage. There's one leaving right now...

Dave

Dear very helpful people,

I started to reply to individuals not being used to this sort of thing. perhaps being born in 1935 has something to do with it.

I am absolutely amazed at the number of people offering to help. And again the vast variety of suggested solutions.

I really aught to go and sit in the corner and try to digest it all.

Are you all single people having no one saying " shall we go and do the shopping now ? "

Should I suggest driving lessons. Perhaps not, we all need to keep safe.

I might have taken pics of he set up and maybe the problem if only I can remember how to post them. I will have a look.

Michael Gilligan's link shows the electric winding set up but not very clearly

Because this problem seemed to be one that I was not going to solve. I have started to alter the clock to hand wind. But will certainly reinstate the electric winding as soon as possible.

Many thanks to all who are trying to help and the mind boggles when you consider the vast number of people who are actually looking and perhaps not taking part.

Stephen ( Old Spice )

Stephen ... We love this sort of thing !!

If you could give details of the motor, that would probably help.

[Sorry; I've just been searching on the BHI archive, but still can't find the specified item]

MichaelG.

I like the suggestion of using a geared synchronous motor of the type used to operate central heating valves.

Rather than winding a chain/weights, have a spiral spring remontoir. If this was selected and properly geared it could drive the great wheel arbor, running at the same speed so the spring is always kept would the same. Or, use an arrangement as on Clock B where the motor runs a worm lifting a weight on a lever applying torque to the great wheel, with a mercury switch to control its level.

If you took the first approach, you could even dispense with most of the clock and just drive the hands direct...

I'll get my coat...

Shirley while raising the weights, all gravitational derived force is removed from the mechanism, so the clock would lose time while winding- (or stop if the raising took a long time)?

.

Huygens sussed how to avoid that problem ... a while back.

MichaelG.

.

Edit: This video is longer than it needs to be, but demonstrates the action nicely:

https://www.youtube.com/watch?v=4JV1IXvoULs

Edited By Michael Gilligan on 10/02/2019 12:18:54

Michael,

Your youtube demonstrates exactly how this works.

My photo's will show two bobbins operating the mercury switch and with a weight resting on the clock weight and a second tension weight. As the main weight raises or falls the switch is tilted.

Stephen S.

Nice clock! I particularly enjoyed this touch:

Must be a grasshopper escapement...

Dave

Rotation detectors are used in industry to detect belt or shaft breakage in critical applications and as posters above have suggested could be an approach to monitoring this application. A thermistor to monitor temperature could work but it really needs to be embedded in the windings to offer the best protection, it could be game over by the time the frame reaches a critical temperature.

Mike

I am resurrecting this thread just to add reference to a two-page article in Horological Journal, dated September 2019

Brian Robertson writes about making the 'Claude Reeve Four-Legged Gravity Escapement Regulator' and includes brief details of his 'Huygens Loop' electric winding.

MichaelG.