Re: Tie Lines was Re: Foreign Exchange (FX) Lines Still in Use?

In article ,

[TELECOM Digest Editor's Note: City of Chicago used DC power (rather > than AC) -- at least in the downtown area -- until sometime around > 1930. That's at least one reason why there were so many WUTCO clocks > everywhere, instead of 'regular' wall clocks. Clocks cannot run on > direct current; they require alternating current at 60 cycles.

I wonder what they did in territory where the generated A.C. power was at 25 cycles.

Or how a battery-operated clock works.

The design _is_ significantly different, because you don't have the 'frequency standard' of the A.C. power to stabilize the timing,

A D.C. powered clock has to employ some other form of a 'regulator' mechanism, rather than relying on the power-line. This is typically a pendulum, or a 'balance wheel', controlling an 'escapement' mechanism. Basically identical to that of a wind-up clock, just using the power-line to keep the mainspring wound up.

A.C. powered designs _are_ 'simpler'. And *MUCH* easier to ensure that multiple clocks keep the same 'rate' of time -- they all link back to the same *single* timing source, the power utility. With D.C. clocks, you have to adjust the 'regulation' on each one, independently. Politely described as a pain in the nether portions of the anatomy. :)

[TELECOM Digest Editor's Note: I will confine my remarks to only your comment on 'how a battery operated clock works' . See my earlier message to Daryl. Wall clocks for example, use the battery to wind the mainspring only. If this were not so, then as the battery ran down, the clock would run slower and slower wouldn't it? Most wall clocks keep on running as long as the battery has the necessary 'juice' to continue winding the spring, and you may note that when the battery begins to get weak, the spring takes a couple seconds longer to wind, but wind it does, and that is what keeps the clock hands moving, _not_ the battery. Truely, when the 'battery runs out' the clock also within a minute or two will stop, but the two events are not connected. You could reach in the back of the battery operated wall clock and rewind the spring by hand. And a true electrical clock does not have to be mounted in a level way; you lay it upside down on the floor for all anyone cared; if plugged in it would continue to run correctly. But try that with a battery/spring wound clock (not having it hung level on a flat surface.) PAT]