[NTLUG:Discuss] OT: Hz

[Fred James]

Steve Baker wrote:
> I'd be very surprised if a small variation in the mains frequency would
> have a huge impact on a normal electrical device.
>
> It is certainly true that in the dim and distant past, things like
> electromechanical alarm clocks depended on the mains frequency to keep
> time - and it's also true that when you use a transformer to convert one
> voltage into another (such as inside the power supply of a PC), then the
> voltage can be affected by a change in the frequency.
>
> However, the change that the power companies are talking about is tiny -
> they aren't talking about letting it vary between (say) 55Hz and 65Hz.
>
> Previous standards required them to keep the frequency between 59.95 to
> 60.05 with an average over a few hours being to withing a gnat's eyebrow
> of 60.000Hz.
>
> What's changing is not the commitment to staying within +/- 0.05Hz but to
> maintaining an AVERAGE of 60.0001 or better over a day.  So your frequency
> might go up to 60.04 for a day or two - where at present, they'd be
> required to drop the frequency back down for a while to compensate.
>
> Overall, that means that those old electromechanical clocks will gain or
> lose time at a rate of a few seconds a day - but nothing else will run any
> differently.
>
> So I REALLY don't believe that anything other than a clock will be able to
> tell the difference.
>
>   -- Steve
>
>
> Fred James wrote:
>   
> (omissions for brevity)
Steve Baker
Thank you for your thoughtful reply.  May I rephrase the question as below?

It would seem logical that since no circuit board is likely to run on 
household current directly, there must be a transformer of some sort in 
the mix.  Might it be reasonable to assume that the resulting voltage 
applied to the circuit board(s) could vary, possibly considerably?  And 
if it does, might that variation be enough to cause the circuit board to 
trip a solenoid, or switch, or some such thing?  If it is of any help in 
consideration of the matter, the appliance causing the most concern at 
the moment is an electric dryer.  And while symptoms might suggest that 
timer switch, diagnostics do not concur.

Thank you again
Regards
Fred James