[Milsurplus] Edison/Tesla battle finally ends in NYC.

[Bob Camp]

Hi

The answer I always got on the bulbs was that the thermal time  
constant on a "real" 25 Hz bulb was much longer than what we now get  
on 60 Hz bulbs. For some odd reason GE stopped making real 25 Hz bulbs  
a while back ....

You do occasionally find stuff like military TTY gear rated for 25 Hz  
power if they thought it would be deployed in the Canal Zone.

One of my first electronic puzzles was a gizmo I found up in the  
attic. I now know it to have been a 25 Hz to 28 volt DC converter.  
They were a popular item back in the early days of suburban  
electrification. Apparently the first customers were people who  
already had 28 volt setups in the house.

Bob


On Nov 22, 2007, at 4:57 PM, D C *Mac* Macdonald wrote:

> I remember touring the power plants on the
> Canadian side of the Niagara River back when
> I was young and lived only about 100 miles
> away.  I could actually see the flicker of bulbs
> running on 25 cps.
>
> Mac - K2GKK
> Oklahoma City
>
>
>
> > From: ham at cq.nu
> > To: Radioman390 at cs.com
> > Subject: Re: [Milsurplus] Edison/Tesla battle finally ends in NYC.
> > Date: Thu, 22 Nov 2007 16:43:46 -0500
> > CC: milsurplus at mailman.qth.net
> >
> > Hi
> >
> > I seem to recall that certain of the NYC subways ran on 25 Hz power.
> > You could tell which ones they were by the way the incandescent  
> bulbs
> > flickered.I believe they still generate 25 Hz at Niagara Falls for
> > some large industrial customers. The same thing is true in the  
> Panama
> > Canal Zone.
> >
> > In all these cases the common denominator is the cost to convert
> > motors from 25 Hz to something else.
> >
> > Bob
> >
> >
> >
> > On Nov 22, 2007, at 4:29 PM, Radioman390 at cs.com wrote:
> >
> > > Con Edison, the local electric utility has finally stopped
> > > generating 120 VDC current for an older section of Manhattan.  
> Edison
> > > fought Nichola Tesla's invention of AC current with a vengeance.  
> He
> > > would have public demonstrations where AC was used to electrocute
> > > animals after they survived a DC jolt. (Yes, animals were harmed  
> in
> > > this research).
> > >
> > > AC allowed step-up andd step-down transformers to make for easy  
> long-
> > > range distribution of power; whereas DC networks required motor/
> > > generator setups. (high voltage on long lines also have a lower
> > > voltage drop because of Ohms Law, and recovering lost voltage  
> can be
> > > accomplished by a step-up transformer).
> > >
> > > NYC had for the longest time into the 60s, a second AC system of  
> 25
> > > Hz, which is why older radios have 25-60 Hz ratings. But DC only
> > > radios are doomed.
> > >
> > > BTW, 400 Hz is used in aircraft beceause less iron is need in the
> > > transformers than a 60 Hz design, saving weight.
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