Re: super series wheelslip control

["Chris Downs" <cvdowns@ozemail.com.au>]

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