[OKDXA] A Puzzle For You...

[Nelson Derks]

Sometimes when I wander the web it leads me to unusual places...

A web crawl that started with the Baldwin (Union Pacific) 'Big Boy' steam
locomotive (135,000 pounds of tractive pull at the rear coupler and 80 mph
top speed) ended up with the Pennsylvania RR's venerable GG1 with 70,700
pounds of tractive pull and a 100 mph rating full-throttle. (8,000
horsepower max)

So, here's the question:

The GG1 ran on electric motors powered from steam, diesel or overhead line
generators at 11,000 volts 25 Hz. Why 25 Hz? Wouldn't a higher frequency be
far more efficient in terms of transformer and throttle controls? We all
know aircraft generators run 400 Hz to reduce transformer weight, surely
lead weights added to a locomotive (for traction) would be better placed at
a low center of gravity than higher above the wheels in the form of oversize
transformers...? All I can guess is that the early rectifier designs (circa
1935) had such a slow recovery rate that 25 Hz seemed like a good idea.
Anyone know for sure?

For more on the GG1 see: http://www.spikesys.com/GG1/
Here are the specs: http://www.spikesys.com/GG1/specs.html

Also, if you think K8FU drives a big rig, think again... THIS IS A BIG RIG:
(woof!)

http://www.steamlocomotive.com/bigboy/4019b.jpg

( See more at: http://www.steamlocomotive.com/bigboy/ )

- AC5UP