[time-nuts] Low cost synchronization, kitchen appliances

Chuck Harris cfharris at erols.com
Sun Aug 21 11:00:10 EDT 2005


Tom Van Baak wrote:

>>still the powerline.  Basically, any appliance, or device that plugs into
> 
> the powerline is likely to
> 
>>use the powerline for its timing function.
>>
>>-chuck
> 
> 
> Correct, my measurements clearly show that
> mains power is steered to UTC. See:
> http://www.leapsecond.com/pages/mains/
> 
> If there's anyone from the power industry on the
> list I'd be interested to hear first-person technical
> details of how phase is synchronized, both short-
> and long-term.
> 
> But I'm not sure I agree with your claim about
> kitchen appliances. It seems to me almost every
> kitchen, electronic, wall-clock, and entertainment
> appliance being sold these days uses quartz-based
> clocks, regardless if they are mains, wall-wart, or
> battery powered. I'm not sure how to confirm the
> accuracy of this hunch, though.

I am just relating my experience with having mucked about
in the insides of these appliances.  Some are quartz,
but those are generally the sort that have an alarm clock
feature (coffee makers)  Any that blink up at 12:00, or,
lose time while the power is off are most certainly AC
derived.

My most recent exposure to an appliance clock is in a
high end electric "double oven" made by DCS.  It uses
a powerline derived clock on its controller board.  The DCS
uses the same controller board as do the GE, Dacor, Kenmore,
and numerous other ovens.  The ovens are of current manufacture.

You can be almost 100% certain that all domestic ovens
will use line derived clocks.  It would take one heck of a
crystal to remain accurate when exposed to the temperature
variations that exist around such a device's controller board.

-Chuck



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