I watched it happen. CVPS was known at the time as your part time
power company. Not the best by any means.
>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.
>>>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
>BIT WORKS Inc.
>905 881 2733
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