Project Journals > RossW

Timer replacement.

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rossw:
Not strictly renewable energy, but it has lots of RE applications.

About 20 years ago, I had a mechanical 24-hour timer whose sole purpose in life was to cycle a pump and filter for a period (typically an hour or so a day). The timer in question was marketed under the brand "Clipsal", and the same switch plate had two additional switches - "Auto/Manual" and "On/Off".


Well, the timer packed up. I was horrified to find a replacement was over $200

So I had a quick search on Ebay and found a small digital one that could switch 16 amps AC 240V. The electronics could be powered from either 12V or 220V (same price, different models). 7 days timer, with 17 on and 17 off events per week, each event can be every day, weekends, odd days, mon-sat, etc. FAR more flexible than I could ever need. It would just about do to control a solar tracker even :)  And the best thing is that it was $9 including shipping!

The only downside was that it's a small timer, designed to fit through a panel and be screwed in from behind. Also, the spade connectors were not going to suit my application.

After thinking about it a bit and looking at it, I took an old switch plate (that I was removing anyway, because it was cracked in the centre). I hoped that I could machine the plastic and not have it shatter and tear. Put the 4-jaw chuck on the lathe, centred the switch plate and nipped it up just firmly. With a boring bar I came in from the face and slowly worked in and across, making what I hoped would be a nice, clean hole 0.25mm smaller than the diameter of the timer. I went only JUST far enough to be through the face.


A quick snip of the support ribs in the back:


And I was left with a fairly clean hole. Some deburring required...


Even at this stage, it was almost a press-fit.


With nothing to screw it to, I needed another way. I was going to pour in some 2-part epoxy, but it was pretty cold, and I was impatient. Ghurd to the rescue:


Next was to drill some holes for the cables so I could do away with the spade connectors.


That worked quite nicely


All that remained then was to put in a connector block, wire it in, screw it to the wall, program and test it.



So all in all, for under $10 and half an hour of my time, I made something that is far more functional and looks pretty schmick into the bargain.

Wolvenar:
Impressive as usual Ross
Nice work

ghurd:
Looks good.

Always kind of surprised how people will pay $250 for something they could do for $10.
G-

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