Re: (ET) E20 motor at 48V

["Konstanty, Walter (GE Indust, ConsInd)" <Walter Konstanty ge com>]

  I think newer ships use multiple turbines driving generators instead
of a huge diesel.....that way they can maintain a "buss voltage" with
only one or two running in port and more come on line when at sea
underway.  The propulsion motors are ac direct drive (maybe 60RPM) and
run off inverter drives from the buss.  Drill ships and some specialized
vessels have 360 degree thruster pods to move and propel the ship.  It's
all high tech nowadays. 
  Many ports are under scrutiny for pollution because they are close to
cities/population centers and a huge diesel idling while
unloading/loading does make a cloud.  Of course, on container crane
ports, hundreds of diesel trucks moving containers don't help.  Time to
go green !

...Walt
-----Original Message-----
From: elec-trak-bounces cosmos phy tufts edu
[mailto:elec-trak-bounces cosmos phy tufts edu] On Behalf Of SteveS
Sent: Thursday, January 03, 2008 10:17 AM
To: et
Subject: Re: (ET) E20 motor at 48V

I used to work summers in a shipyard. One time we had a freighter in,
the "Marine Electric". It had one of those motors and it was strange how
narrow it was, but huge diameter.  As I recall it was: steam turbine to
generator to electric motor. Seems inefficient, but evidently, gearing
down a turbine is not so efficient and very expensive. The motor drove
the shaft directly.

- SteveS

Konstanty, Walter (GE Indust, ConsInd) wrote:
>      High speed motors are stacked out for low inertia and high speed.
> The Disney Cruise Ships are powered by 2-60,000HP ac motors that are
20'
> high but only 3' long.....low speed, high torque for propeller shafts.
>  ...Walt
>
>   
>
>
>   


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