I would suggest perhaps the clock in question was not synchronous with 
the power system but a "slave" clock which may have been tied to a 
master clock ,which may have been synchronous to the power system (most 
of the time). The master clock could send extra pulses to advance slave 
clock(s) to advance thee time. I don't think the power main could change 
frequency a drastic amount.

On 11/29/2015 12:09 PM, Robert Cham wrote:
> 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!
>

-- 
John Gledhill
BIT WORKS Inc.
905 881 2733
[log in to unmask]