Re: super series wheelslip control

[jjjim <jjjim@bigpond.com>]

Blah Wheres the fun in that.

:p

Chris Downs wrote:

> James Robinson <wascana@my-deja.com> wrote in message
> news:3AAE34A8.FE615E21@my-deja.com...
> > niged@bigpond.com wrote:
> > >
> > > can anyone help me with the super series wheel slip control and how it
> > > works .
> >
> > Super Series was introduced by General Motors to take advantage of a
> > phenomenon called wheel creep.  It was where wheel slip control became
> > adhesion control. In short, the highest tractive effort will be obtained
> > from a locomotive when the wheels are allowed to turn slightly faster
> > than the locomotive is moving.  If a locomotive is moving at, say 15
> > km/hr, and the wheels are turning at 16 km/hr, then the locomotive can
> > be said to have 1 km/hr wheel creep. This is a typical value, but the
> > desired amount of creep will vary with the condition of the rail, and
> > can range from practically nothing to 5 or 7 km/hr. The benefit of all
> > of this is that a Super Series locomotive can pull from 25 to 40 percent
> > more up the ruling grade than locomotives with older wheel slip control
> > systems.
> >
> > With the older systems, when a wheelset loses traction, the locomotive
> > would detect this and lower main generator excitation, and therefore the
> > power applied to all driven axles.  Once the spinning wheel was brought
> > under control, then the power would be reapplied.  This results in a
> > loss of average tractive effort.
> >
> > With Super Series, the adhesion control system is always trying to find
> > the maximum tractive effort, and will allow a certain amount of wheel
> > creep to achieve it.  The control system can also quickly detect when a
> > wheelset has lost traction, and can bring it under control more quickly
> > than older systems, so the power cuts are not as deep or as long,
> > resulting in higher average tractive effort.  The control of the power
> > is still handled by main generator excitation, so if one axle slips,
> > then the power still has to be cut to all axles to recover.  The added
> > complexity and cost of separate axle control was not considered
> > justified on DC traction locomotives.  Super Series locomotives also
> > have a doppler radar system which is used to determine actual ground
> > speed of the locomotive.  The radar can occasionally get confused by
> > heavy rain or water between the rail, so the locomotive has a
> > traditional wheel slip control system as a backup for these occasions.
>
> Always thought this'd be perfect for a retro-fit on V-sets, no creep of
> course, just match the power to stop wheel slip.
>
> For anyone in the know how does G7 (CityRail's AC motored set) deal with
> wheelslip compared with DC motored sets?  And of course what are the
> Millennium sets going to use (same as G7)
>
> Ta
>
> Chris
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