This seems like another case where gas might simplify things...
Think I'll save this kind of automation for when I have a big still.
Thermostats on Still
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junkyard dawg
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Uncle Remus
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How long does it take an element to heat up? When I plug in my element at the beginning of a run, I get some fizz (carbon dioxide) within a second or two. This tells me that the element doesn't have enough thermal inertia to keep the power level from changing over the time frame of a second or two. So if you are doing "smooth" power control by doing fast on/off switching, you'd better be flipping it at least several times a second.Although elements possess thermal inertia ...
Flipping at the zero crossings of your 60hz (or 50Hz) AC provides some nice electrical benefits, and should be sufficiently fast. The thermal inertia of the element is probably enough to smooth out 60hz on/off flipping. I have no experience to support this claim.
I'm using 2 seconds cycle time (i.e. 2 secs divided into percentual on/off time) and it works well. You can barely notice small fluctuation in power in my see through boiler. With 1 sec cycle time it's unnoticeable. The point is that small fluctuations in power are masked by the liquid mass of the mash and with longer cycle time you get more accuracy when using large heating element. With hotplate you can use even longer cycle time as the plate in itself has enough mass to absorb a lot of fluctuation.
How long does it take an element to heat up? When I plug in my element at the beginning of a run, I get some fizz (carbon dioxide) within a second or two. This tells me that the element doesn't have enough thermal inertia to keep the power level from changing over the time frame of a second or two. So if you are doing "smooth" power control by doing fast on/off switching, you'd better be flipping it at least several times a second.
Flipping at the zero crossings of your 60hz (or 50Hz) AC provides some nice electrical benefits, and should be sufficiently fast. The thermal inertia of the element is probably enough to smooth out 60hz on/off flipping. I have no experience to support this claim.
Cheers, Riku