B
bitrex
Guest
On 4/14/2022 9:36 AM, bitrex wrote:
Er, DC motor size rather the DD1 was DC-powered. Both AC and DC motors
decreased in size over that time though for similar reasons I think
On 4/13/2022 9:15 PM, Cydrome Leader wrote:
bitrex <user@example.net> wrote:
On 4/13/2022 5:11 PM, Cydrome Leader wrote:
RichD <r_delaney2001@yahoo.com> wrote:
Today the electric cars are the quickest on the road.
The classic petrol muscle cars are vying for the silver medal.
Was it obvious to the designers, from day one,
that this would be the case? Is it simply a power/weight calculation?
I\'m congenitally leery of simple explanations -
--
Rich
electric motors have a far more useful torque curve too. That\'s why
train
locomotives are not direct drive in the civilized world but run a
generator and traction motors. If you want to pickup speed fast,
there\'s
nothing better. If you\'re hauling freight, and need starting torque,
there\'s also still nothing better than an electric motor.
Incidentally there were some torque-converter driven trainsets in the US
for niche applications e.g.
https://en.wikipedia.org/wiki/Budd_Rail_Diesel_Car#Design
Basically a city bus on rails.
The later SPV-2000 was similar but an unreliable and difficult to
service design it seems:
https://en.wikipedia.org/wiki/Budd_SPV-2000
What odd machines. I recall diesel operated light duty railcars in
Ireland about 15 years ago.
They made strangest sounds when operating. I think they were made in
Korea. For the intended
use of moving light weight trains around, I guess the worked fine. The
north american train
standard are unlike anywhere else in the world except maybe russia, so
the entire concept of a
fast light weight train just isn\'t happening here. Essentially
passenger trains have to survive
a very small crash with a freight train, and we have the biggest,
heaviest railcars. They will
obliterate any trains made anywhere with the exception of russia.
The FRA imposed some big-time regulation on passenger rail vehicle
strength after WW2, yeah. I think those are _maybe_ getting finally
relaxed a bit as of the past couple years? Not sure with respect to
diesel rail cars on freight lines maybe I\'m thinking of something else.
It\'s too bad as light weight DRCs that could run alongside freight
equipment would open up possibility of service on under-served routes
like e.g. Worcester MA -> Providence, RI and Boston -> Nashua, NH (just
as local examples I know of) where there\'s some demand but hard to make
the numbers work either as a public service or commercial venture with
heavy rail.
When AC traction motors were still quite large jackshaft-driven
locomotives were pretty cool-looking:
https://en.wikipedia.org/wiki/Jackshaft_(locomotive)#/media/FileRR_DD1_running_gear.jpg
Ha, never seen that before, but it makes sense as that\'s the only way
they made large motors
back then. I\'m not completely sure why though. Were there no motors
with long skinny rotors at
all, sort of like a modern servo motor where minimal inertia is key?
Maybe, there were some DC motors that fit between the wheels then. The
shafts on those in the pic are huge though, I think at the time around
the turn of the century engineers were very conservative with this new
technology and their main concern was ensuring they had enough torque
hence the giant shafts. But there were many improvements in insulation,
core material, bearings etc. from 1910-30 and the AC motor size
decreased rapidly
Er, DC motor size rather the DD1 was DC-powered. Both AC and DC motors
decreased in size over that time though for similar reasons I think