[time-nuts] Mains Frequency

[d.schuecker at avm.de]

The Berlin grid was isolated from '48 until begin of the '80s. Berlins 
BEWAG was very proud of running a stable net on this island. They used a 
big bunch of energy storage devices: steam under pressure, batteries etc. 
to keep the frequency and phase stable. In begin/mid '80s they built a 
380kV power line from West-Germany (Buschhaus) to Berlin crossing the GDR. 
So Berlin was hooked to the west-european frequency. 

After the fall of the wall they disconnected this line and hooked up to 
then USSR driven east german grid. That was for commercial reason, 
reportedly they saved a Million Marks a day. So Berlin had the same grid 
frequency as Moscow, and many clocks on churches, towers, the city hall, 
public clocks on poles etc. ran on that frequency. The USSR grid had a 
much bigger limit on the phase, so the grid driven clocks sometimes lost 
or won 15min a day, as far as I remember. Sometime in the '90 they 
switched to the west-european grid for then reunified Germany. 

There were similar developments for other european satellite states of the 
USSR, i.e. Hungary. They had a long direct 750kV DC-connection, for a 
great distance you use DC. In '92 I visited the DC/AC converter in 
Budapest, installed in a rather big hall. It was cooled by de-ionized 
water, which was so aggressive to get ions that they could not use any 
metal for fittings but they had to use glass. In this big hall there was a 
fairytale castle made of glass pipes, tubes, coolers etc., very 
impressing.

In the old times :-|
Cheers
Detlef Schücker


"time-nuts" <time-nuts-bounces at lists.febo.com> schrieb am 12.02.2021 
20:41:25:

> Von: "Alex Pummer" <alex at pcscons.com>
> An: time-nuts at lists.febo.com
> Datum: 12.02.2021 22:39
> Betreff: Re: [time-nuts] Mains Frequency
> Gesendet von: "time-nuts" <time-nuts-bounces at lists.febo.com>
> 
> at the time I grew up in Eastern Europe -- "communist time" -- they kept 

> he clocks using the line frequency as reference -- by counting the 
> periods during the day and week and for longer time for equal time 
> interval the "provided" equal number of line frequency periods, as 
> longer the time interval was as more precise was the time.  That way the 

> clocks were relative accurate. They could do it since everything was 
> "central governed".
> 
> On 2/12/2021 9:24 AM, Lux, Jim wrote:
> > On 2/12/21 8:23 AM, Thomas D. Erb wrote:
> >> "I would think they try to hold it over 1 day, so that mains driven
> >>
> >> clocks don't run slow or fast.? That being said, I wonder how many
> >>
> >> clocks are still being built using a synchronous motor drive? Given 
that
> >>
> >> all the clocks on appliances in my kitchen have drifted apart, I'll 
bet
> >>
> >> they use their internal microcontroller crystal as a reference."
> >>
> >> Actually I think all of my kitchen appliances use line frequency for 
> >> time reference - it's so easy to count.
> >
> >
> > Maybe.. you've got to condition the AC from the secondary side of the 
> > transformer and use a pin to bring it in on, which requires at least 2 

> > or 3 passive components, and you already have a crystal for the 
> > microcontroller (thinking here of oven timers and the like, which have 

> > a numeric display).  These applications are super price sensitive, and 

> > those 2 or 3 components cost money, in components, in board space, and 

> > in assembly costs. Pennies to be sure, but...
> >
> > And the fact that my appliances drift on the order of a minute in a 
> > month, differently. So maybe some count cycles and some have a rock.
> >
> >
> >
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