Subject:
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Re: My EMD SD40-2
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Newsgroups:
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lugnet.trains
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Date:
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Wed, 23 Feb 2000 02:54:37 GMT
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Reply-To:
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{lpieniazek@novera.}spamless{com}
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Viewed:
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1256 times
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Christopher Masi wrote:
> Thanks for the extra info, I'll add the blower information instead of just calling it a
> bulge. I assume blower means supercahrger?
No, the blower is a massive device that provides air, via ducting, to
the traction motors to keep them cool. The ducting can be rather
elaborate, since the motors are mounted on the trucks (side hung and
connected via gears to their drive axle) and the ducting has to wend its
way from the centrally located blower to both trucks via openings in the
frame. Blowers are electrically operated. Traction motors are
transferring (in the case of an SD40) something like 660 HP each (there
are 3 motors per truck on a SD, and therefore 6 motors delivering 4000
HP) which tends to generate a bit of heat in the windings.
A blower failure can be rather spectacular especially if the engine is
on a drag freight (slow speed) and the crew doesn't notice it (if it's
say, not the lead unit). Traction motor heat just builds and builds...
I've heard of windings melting into copper puddles which of course makes
for fireworks displays of electrical shorts... that can burn out the
main generator or the switch gear if not caught in time..
This is rather rare these days, modern locos use microprocessor control
and any rise in traction motor temp would be immediately noticed (as
would amperage draw changes from the blower motor) by the control
program. But I know of at least one FT set it happened to.
Superchargers, when the prime mover is so outfitted, are typically
mounted atop or astride the engine in a position to provide pressure to
the intake air, and are much smaller. A blower can be the size of a
closet. Superchargers are engine belt driven (contrast with
turbochargers, which are exhaust gas driven.)
The hood side bulge is, I believe, actually ducting rather than the
blower itself, the engineers ran out of room to route the ducting neatly
(most designs are incremental and not every component is rearranged or
changed, so sometimes stuff doesn't quite fit)
So what does SNOT mean anyway, Sproat?
--
Larry Pieniazek - lpieniazek@mercator.com - http://my.voyager.net/lar
http://www.mercator.com. Mercator, the e-business transformation company
fund Lugnet(tm): http://www.ebates.com/ ref: lar, 1/2 $$ to lugnet.
Note: this is a family forum!
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Message has 2 Replies:
 | | Re: My EMD SD40-2
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| (...) snip the rest of the answer Thanks, I was basing my guess on the slang blower = supercharger; I couldn't remember if the SD40-2 were turbo/supercharged. No need to answer that one I can look it up when I get home. I have to laugh...what is a (...) (25 years ago, 23-Feb-00, to lugnet.trains)
| | | Re: My EMD SD40-2
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| (...) Oops, sorry so late... It seems someone (;-) introduced this thread into lugnet.build (which I read daily), with followups immediately to lugnet.trains (which I don't normally read). I kept wondering why there was no further discussion on an (...) (25 years ago, 25-Feb-00, to lugnet.trains)
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Message is in Reply To:
| | Re: My EMD SD40-2
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| Thank you, thank you, thank you! Building is great fun, but I have been all smiles reading what you have been saying! Yeah, I have a problem with the railing too. It is just not right, but without the railing it looks unfinished. I was thinking that (...) (25 years ago, 23-Feb-00, to lugnet.trains)
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