Any ideas for how to read this mechanical timer?

[AbdullahS]

Hi all, just came across this timer while on a site-visit. Any idea how to read this thing?

PS: if it is not a right section, please move it to the right one as I was not sure where to post this.

Regards,
Abdullah

 

[Guineafowl]

It looks like the blue ring rotates around the 24hr clock, and lift-up tabs or pins inserted at particular times in the rim toggle the switch at top right on and off. It’s 1 am and the switch is on in the picture.

 

[DaveC426913]

It looks like the blue ring rotates around the 24hr clock, and lift-up tabs or pins inserted at particular times in the rim toggle the switch at top right on and off.

Agree.

It’s 1 am

Not so sure.

There's no indication that this particular timer is supposed to show what time of day it is - simply that it is meant to keep a 24-hour cycle.

It certainly can be, I've just never seen one that doesn't give hints about day/night.

 

[Guineafowl]

Agree.Not so sure.

There's no indication that this particular timer is supposed to show what time of day it is - simply that it is meant to keep a 24-hour cycle.

It certainly can be, I've just never seen one that doesn't give hints about day/night.

I suppose you could set any time you want, and it would run with a constant offset to real time, but it makes more sense to set it to real time, surely?

 

[DaveC426913]

but it makes more sense to set it to real time, surely?

Only if it remains accurate.
If it can't be relied upon to always show the time then it would be folly to set that up as an expectation.

For example, if the system doesn't have a constant power source - or the power is frequently reset - then it's useless as a clock. Indeed, worse than useless.

I have no basis for thinking this is so, simply a feeling, coming from the fact that this dial looks unlike a clock - it doesn't even try to look like a clock. It looks like a 24-hour countdown timer.

AM/PM:

vs.

 

[anorlunda]

It looks like the blue ring rotates around the 24hr clock, and lift-up tabs or pins inserted at particular times in the rim toggle the switch at top right on and off. It’s 1 am and the switch is on in the picture.

Bingo, that's it. It is a user programmable time-of-day on/off switch. I think is supposed to have two kinds of those blue riders, or two positions. One for on, one for off. Multiple pairs of the riders can program multiple on/off periods during one day. Control of a hot water heater would be a good use. Kind of old fashioned, but easy to understand, and it does the job.

It does need constant power to keep accurate time. A more modern switch could use digital electronics and a battery to keep the clock running when power is interrupted. But the modern one needs a user manual, and if the manual is lost, nobody remembers how to program it.

 

[Guineafowl]

Only if it remains accurate.
If it can't be relied upon to always show the time then it would be folly to set that up as an expectation.

For example, if the system doesn't have a constant power source - or the power is frequently reset - then it's useless as a clock. Indeed, worse than useless.

I have no basis for thinking this is so, simply a feeling, coming from the fact that this dial looks unlike a clock - it doesn't even try to look like a clock. It looks like a 24-hour countdown timer.

AM/PM:
View attachment 248389

vs.

View attachment 248387

I’ve just remembered that somewhere I have a timer switch like this. It has an on ring, and an off ring. The dial reads in hours of the day, and it’s intended for things like switching a security light on and off at particular times, like if you’re on holiday and want it to appear like you’re home. You set the pins as required, then spin it so the displayed time matches real time.

For our UK power supply, it’s reasonable enough to assume the power will stay on reliably enough for this to stay in with real time. If you can’t rely on this, then a 24-hour cycle timer, offset or not, isn’t much use.

The mechanical timer can be set intuitively, but I have a digital one as well which requires a hard-to-find manual for operation, or a good 15 minutes’ fiddling.

 

[sophiecentaur]

A trip down memory lane, I think. That is the sort of timer that everyone would have recognised, used and loved, a couple of decades ago. A synchronous motor would probably been inside it which, of course, couldn't have battery backup. But the news is not all bad because it will tell you how many hours the supply was actually on for (modulo 24 of course). Placed downstream of a thermostat, it would tell you how long a heater had been running .
@AbdullahS You can find out exactly how to use that thing by playing with it. Choose any spot or mark on the side for your zero reference for setting the clock and see which way those 'fingers' work (i.e which is on and which is off). Immune from the millennium bug and all malware.

 

[arydberg]

Agree.Not so sure.

There's no indication that this particular timer is supposed to show what time of day it is - simply that it is meant to keep a 24-hour cycle.

It certainly can be, I've just never seen one that doesn't give hints about day/night.

You cannot set a 24 hour cycle if you do not know the time of day.

 

[sophiecentaur]

You cannot set a 24 hour cycle if you do not know the time of day.

That's true for any clock that doesn't have network connection of some kind. Using that sort of timer, you have to make a decision whether a 24 hour cycle - with a hiccup of four random hours is better than losing time altogether. The very early synchronous mains clocks would not start until you pressed a button to get the motor going so they would just stop at the (Hercule Poirot style) time of the crime/

 

[DaveC426913]

You cannot set a 24 hour cycle if you do not know the time of day.

Of course you can.

I need my pool pump to run for 4 hours a day. I do not care what time of day it does so.
The timer, as-shown, will allow me to set a window of 4 hours on, 20 hours off.

 

[sophiecentaur]

The timer, as-shown, will allow me to set a window of 4 hours on, 20 hours off.

It's a matter of 'horses for courses'.

 

[DaveC426913]

It's a matter of 'horses for courses'.

Right.
My primary point being that the timer itself suggests what's important in this application is a 24 hour cycle, whether or not keeping correct time is an issue.

 

[arydberg]

Of course you can.

I need my pool pump to run for 4 hours a day. I do not care what time of day it does so.
The timer, as-shown, will allow me to set a window of 4 hours on, 20 hours off.

Correct. but this is an exception. I usually see these timers switching things like christmas decorations. or driveway lights where time of day is important. Your application is my first encounter of not requireing the time of day.

 

[DaveC426913]

Correct. but this is an exception. I usually see these timers switching things like christmas decorations. or driveway lights where time of day is important. Your application is my first encounter of not requireing the time of day.

In post 5, I attached a pic of a timer (the small pic) that is intended to be set to the correct time. It has several ease-of-use indicators: AM/PM markings, as well as day/night colouring.

The fact that the timer in the OP is lacking these indicators hints that such functionality may not be important for this application. (Not a certainty obviously, simply noting that sometimes an absence of a thing can tell us about a thing.)

 

[anorlunda]

Correct. but this is an exception. I usually see these timers switching things like christmas decorations. or driveway lights where time of day is important. Your application is my first encounter of not requireing the time of day.

Why not have a second device with the correct time?- you can see the timer's time from that.

Just a few decades ago we had billions of clocks and watches with no way to tell if they showed the correct time. That era seems to be forgotten already.

 

[sophiecentaur]

You cannot set a 24 hour cycle if you do not know the time of day.

That's rubbish. If the supply is not interrupted, you will get a 24hour cycle. Clock time is another issue.

I usually see these timers switching things like christmas decorations. or driveway lights where time of day is important.

That is an example of when you need to know approximate local time. But that applies to absolutely any timer system. You seem to be implying that this old mechanical thing is no use. Without the internet or a satellite feed etc, any (even quartz) electronic timer will fail you - moreover, an interrupted supply - even just a minute or two - can lose your fancy electronic job's total knowledge of what time it is (00.00). A short interruption of supply for the mechanical will just give a small slippage and it will do its job quite well enough for many purposes.
Electronic is not always 'better'.

 

[DaveC426913]

... an interrupted supply - even just a minute or two - can lose your fancy electronic job's total knowledge of what time it is (00.00). A short interruption of supply for the mechanical will just give a small slippage and it will do its job quite well enough for many purposes.
Electronic is not always 'better'.