[time-nuts] The need for quartz crystals and mains frequency

[Jeremy Nichols]

Interesting comment about non-self-starting clocks. I have an old “FDR”
clock with a synchronous motor; it has to be started by spinning a knob on
the back. The case has molded into it the words, “F.D.R., The Man of the
Hour.” I suppose it dates from just after 1933 when Roosevelt became
President.

A couple of my HP quartz frequency standards use non-self-starting dividers
to take 1 MHz down to 100 KHz. Failure of either power or signal causes the
divider to stop; a manual restart button is used to start the divider. Loss
of the 100 KHz output is thus a signal there has been an interruption.

J


On Sat, Feb 13, 2021 at 12:55 PM Thomas D. Erb <tde at electrictime.com> wrote:

> My firm has electrictime.com  - sold power station master clock as part
> of Telechron - now we just make big tower and street clocks.
>
> We have a bunch of master clocks in our museum - two in our on-line
> exhibit - I'm hoping to get a small article in IEEE Spectrum. One master
> clock was made in an vacuum chamber with an invar pendulum.
>
> My clocks are shown
> https://electricclock.omeka.net/items/show/6
> https://electricclock.omeka.net/items/show/12
>
> Mark Frank has some restored units at
>
> http://www.my-time-machines.net/master_clocks.ht
>
> In the 1970's we made a cheap power station clock for some islands - it
> consisted of a synchronous wall clock next to a quartz battery power clock
> - the operator keep the synchronous clock in phase with the quart clock.
>
> BTW the little red flag was a part of a patent fight - Telechron had a
> patent  on self-starting synchronous motor the non-self-starting clock
> companies got a law or regulation that a clock had to had a notification
> power had been off - they thought they had him - but he came up with a
> creative solution.
>
>
>
> Thomas D. Erb
> p:        508-359-4396
> f:        508-359-4482
> a:        97 West Street, Medfield, MA 02052 USA
> e:         tde at electrictime.com
> w:        www.electrictime.com
> Tower & Street Clocks Since 1928
>
> _______________________________________________
> time-nuts mailing list -- time-nuts at lists.febo.com
> To unsubscribe, go to
> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
> and follow the instructions there.
>
-- 
Jeremy Nichols
Sent from my iPad 6.