Re: (erielack) Tractive effort and loading characteristics

[Ken <erie910_@_harborbeach.com>]

EMD engines used a Woodward governor.

Ken B.

At 05:01 PM 3/20/2003 -0500, bob gillis wrote:

>Going way back in my memory, I think this is the story.
>
>"Loading" is how fast the diesel engine can get up to full speed and
>load.  It has nothing to do with the electrics.  An EMD 2 stroke engine
>with a roots mechanical blower can rev up faster without excessive smoke
>than can an AlCO or GE 4 cycle engine with a turbocharger .  The rate
>the engine accelerates is controlled by the engine governor.  EMDs and
>the later GE engines used a third party governor whose name escapes me
>but the company was from Rockford IL, and the earlier ALCOs used a GE
>governor.
>
>"Lugging" referred to how much the hard the electrics could take,  GE
>was usually more advanced in generator and traction motor design and
>insulation.  The GE traction motor was a GE752 and may still be.  The
>EMD traction motor was taken from a GE design about a GE72X or GE73x
>version.  The GE731 was used in ALCO switchers. (The GE in the traction
>motor was a series designation for traction motor; I can't remember what
>a generator was but a motor-generator was a GMGxxx)
>
>The EMD motor used a cast frame and the GE752 used a welded frame,
>There was more room in the welded frame and the coils and iron could be
>larger,  Also GE was in the forefront of insulation design and the 752
>could run hotter longer that the EMD.
>
>When GE was competing with ALCO in the domestic locomotive market, the
>traction motors sold to ALCO would have been the same as the ones used
>on the GE locos.  Generators would have been different and the control
>system also.  But the ALCO electrics would have been almost as good as
>the GE locos.
>
>bob gillis
>
>Christopher Thurner wrote:
> >
> > Listers:
> >
> > A great thread and very informative responses from our 'in-the-know' 
> members who attended prestigious institutions such as Stevens Tech and 
> Penn State.  You've removed a lot of the 'fog' from a topic I knew little 
> about and obviously didn't understand until now.
> >
> > I've read in many other publications and heard from former engineers 
> that the EMD's loaded quicker and the GE / Alco's loaded slower, but were 
> better luggers.  I don't doubt this at all, both from the assertions of 
> the people who operated them and the technical people who explain why 
> this is so.   One oddity I find, is, that at first glance it seems 
> counter-intuitive.  It would seem to be the opposite, as one would 
> surmise that EMD's expertise would be in favor of the prime-mover, given 
> that its part of GM.  Likewise, one would expect GE's to load faster, 
> given GE's core expertise was / is in electrical components, not the 
> prime mover (remember Alco's used GE electronics / electrical components, 
> albeit that after GE became serious about building road units before the 
> release of the U25b, Alco was then relegated to receiving GE's second 
> rate components, as GE reserved its newest and best for their units - 
> another factor in both the demise of Alco and why Centuries weren't f!
>ri!
> > endly to mechanical depts.).
> >
> > Now, I also realize that a significant factor that can override this is 
> the design objectives of the builder.  Maybe GE / Alco's design 
> priorities were to build a superior puller and EMD's to build a racehorse.
> >
> > Can anyone on the list shed any light on this?
> >
> > Regards,
> >
> > Chris Thurner
> >
> >
> >
> > ---------------------------------
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> > Yahoo! Platinum - Watch CBS' NCAA March Madness, live on your desktop!
>
>
>
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