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I watched it happen. CVPS was known at the time as your part time power company. Not the best by any means. Bob >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 >> > >-- >John Gledhill >BIT WORKS Inc. >905 881 2733 >[log in to unmask] > >!DSPAM:639,5659d7c989736379691430!