Alec Cameron wrote in a message to Roy J. Tellason:
 AC> On (27 Oct 96) Roy J. Tellason wrote to Alec Cameron...
 AC> Maybe you remember the old Tungar chargers- these were a 1/2 
 AC> wave setup, a glass tube mercury diode the size of a 150 watt
 AC> lamp having a plate lead at top and a GES base 
 RJ> What's a "GES base"?  (I probably know these,  but not by that name.)
 AC> Giant Edison Screw. Like your regular 110v lamp bases but 
 AC> larger, about 1 1/4 ins dia, due to the very heavy current for 
 AC> the filament- about 25 amps. 
About what I thought...
The unit I remember my grandfather having didn't seem to be a whole lot 
larger than a pretty standard light bulb,  maybe it wasn't that heavy a 
current charger.
 RJ> I think that if I ever do rig some of these up I'll add some of those
 RJ> variable duty cycle astable circuits (what Don Lancaster showed as being
 RJ> for a "caver's lamp" in his CMOS Cookbook) to give me control over
 RJ> brightness.  They sure do come on bright when I hit that test button!
 AC> For that reason, some large batteries are provided with "end 
 AC> cells". The charger floats across [say] 55 cells but the load 
 AC> is connected across only 50 of these. When an emergency arises 
 AC> and the battery volts fall after [say] 15 minutes loading, a 
 AC> contactor would automatically switch in the rested 5 end cells. 
 AC> Presto! 110 volts at the loads isntead of maybe 125 immediately 
 AC> at the start of the emergency.
Hmm.
 RJ> Even looking in the Sylvania book at the auto parts store I can't find a
 RJ> reference to the bulbs in this thing,  H126 is the number.  I'd be
 RJ> curious to know what kind of power they're drawing at full 
 RJ> briliance.  Probably a bunch.
 AC> Sylvania has no trade here, in auto lamps. 
There's other stuff out there,  I just looked there because the book was 
handy at work...
 RJ> Anyone know how long emergency lights are supposed to stay lit?
 AC> How long is a piece of string!  For cinemas and large stores, 
 AC> this is probably legislated by State or City laws. For 
 AC> submarines, I guess one week. For modern generating stations, 
 AC> just an hour or two- long enough to start up and switch in, the 
 AC> emergency diesel or gas turbine generator. For railroad cars, 
 AC> maybe 4 to 6 hours.   Cheers....ALEC
I guess it would depend on the application.  There must be *some* fairly 
commong standard because these things are all over the place in various 
retail stores,  etc. and the mfr's won't want to make too many different 
kinds.  I guess that's the number I was looking for...
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