Where would I look for a timer that would turn on an AC circuit for a short
time. Slightly different than the outdoor light timers, for I would like to
turn if on for small amounts of time, say five minutes every two hours.
Some of the digital timers can do this, but it's very hard to find them
in a "local store" and very hard to tell in any detail what the timing
limitations are on ones you buy mail-order until you actually get them.
Let's see if I can find a link to the one exception I found (there may
be many I did not find) to that rule, but with the added disincentive of
a price too rich for my budget.
Not the same one, but at a much better price than the one I recall and
from MSC (so probably available elsewhere, cheaper) is the Intermatic
DT17C, claiming 14 on/off cycles per day with a minimum ON time of 1
minute, at $36.83 (not all that high-powered, but you haven't said what
Actually, some sort of low end PLC might be the ticket, but I don't have
any direct personal experience with them.
What are you trying to do exactly? Please use as much white space
as needed to explain... ;-)
If it has to be at actual and precise times each day, my first
thought is an electronic timer like the Intermatic Digitals - Bad news
the ET100 only does 8 operations (4 cycles) per day, but good news
they are in one minute increments. The ET171 series will do 20
operations per day (10 on, 10 off...) They have fancier ones, but
they get more expensive.
If you just want to run a battery charger once or twice a day, you
can use something cheap like a plug-in wall timer.
If you need to have a piece of equipment start, they have little
solid state cube time delay relays that can be wired as a really long
period interval timer. Two hours off, five minutes on. But they are
not precise, so that period will slip around the clock - it won't
always be at 2 AM, 4 AM, 6 AM, 8 AM 10 AM...
Their site sucks, and so does their customer service.
Unfortunately some of their products can only be obtained through
them, but for me, never again.
Fortunately other people carry most of what he might want.
Lots of industrial timers will do what you want. They mostly come
with a decent range of selectable of values/units, with timing on
each range from 1 to 999 as I recall. Have a peek at :
For instance, if you select 0.001 seconds, you can time from .001 to
1 second, or select the 10 second range and you can time from 1 to 999
seconds (16-1/2 minutes). The ones shown at the above will do from
.001 seconds minimum with the minimum unit size selected, to 300
hours maximum with the maximum unit size selected.
All very easy to "program" too. Availability at any electrical
wholesaler in the brand(s) he deals with.
I used an analog clock for similar purposes, my latest variation turns
on a 12vdc pump for 3 min every 15 min. I soldered wires to the hands
and used aluminum foil on the face to make contact to operate a relay.
Really crude but cheap & worked.
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