What is your source for this ?
I think almost all utility power generation equipment is heavy (as in
massive) and there is no "jumping" going on. Only slow variations.
Who told you about jumping three minutes at noon?
I do remember sitting in public school in Toronto in the 60's and
watching the wall clock above the door advance an hour very quickly
after day light savings switch. I was impressed. Usually I thought the
clock was running very slowly.
I assume they were no connected to the mains but a separate line which
could be used to advance or retard them.
On 11/28/2015 10:47 AM, Robert Cham wrote:
> In the mid '80s in central Vermont, the frequency was highly
> variable. The standard at the time called for X cycles in 12 hours.
> You could watch synchronous clocks jump as much as three minutes at
> noon as they made up the necessary cycles, Hz today.
> Bob Cham
>> For what it's worth, in the early 1950's, from 1951 until 1954, there
>> were times in Minneapolis and Chicago when my father would have to
>> use Fairchild's Pic-Sync system to assure correct pitch/speed in his
>> recording truck. The truck's power panel had a frequency meter that
>> monitored the power line. He said Minneapolis in particular had
>> unreliable power frequency in those days. The tradeoff with the
>> Pic-Sync system as originally designed is that there's a sharp
>> rolloff above 10kHz, because the Pic-Sync signal is at 14kHz.
>> However, using modern methods to lock to and then remove the Pic-Sync
>> signal, in tests done by Jamie Howarth and myself, we recovered
>> usable audio above 10kHz. There seems to be recorded information up
>> to, at and above the 14K frequency, the rolloff occurs only in the
>> playback. When the Plangent Process is used to lock to either bias or
>> the Pic-Sync signal, the band of the tone is very narrow and can be
>> notched out, leaving a lot of audio information that would have been
>> sharply rolled off by Fairchild's Pic-Sync playback system (resolver)
>> or similar devices. We found surprisingly little beating and other
>> interaction with music audio. I have to say, the whole thing
>> surprised and impressed me, the quality and the frequency range of
>> the audio recovered. I would certainly never use an analog Pic-Sync
>> resolver again, for any Pic-Sync tape.
>> In contrast to the variable Midwest power frequencies in the early
>> 50's, another power system story oft-told by my late friend and
>> mentor Bob Eberenz concerned Manhattan during hot summers in the
>> 60's. While the frequency would be rock-solid 60Hz, the voltage could
>> drop as low as 95V in Midtown, overheating the wiring and various
>> pieces of equipment. Bob obtained some massive step-up transformers,
>> and could thus keep the control rooms running on 110-120V under most
>> circumstances. He said the big lines coming into the building in the
>> sub-basement would be so hot you could pour water on them and it
>> would boil right off.
>> -- Tom Fine
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