SCADA (was Re: Help to identify a computer?)

[Bob Bradlee]

On Sat, 17 Feb 2007 20:48:33 -0800, Brent Hilpert wrote:

>Chuck Guzis wrote:
>> coke-oven (producer) gas.  For some reason never made clear to me,
>> one of the competing "standards" for AC distribution was 25Hz (both
>> 50 and 110v).

>Didn't the 25 Hz stuff have it's origins in turn-of-the-century
>electric-train/streetcar technology? ..such established systems then being
>extended into residential/industrial use in some areas. There were a few
>30's-era radios made for 25Hz, distinguished by their oversize power transformers.

I remember commenting about the lightbulbs flickering in the NY subway and my dad tellling me that the 
subway operated on 25 cycle. this was close to 50 years ago. I asume it has been upgraded by now.

Bob