Re: 82's Leading Patricks West- Question on 82 cl gear ratios & what about using the Cs and the DLs

["Grahame Ferguson" <grahamef@users.mcmedia.com.au>]

On 17/8/99 John MacCullum wrote:-
>Yes Mauire , I was somewhat puzzled by the difference in the Tractive
>effort between 81 and 82 classes but I was even more surprised about the
>lack of tractive effort available from NRs.
>
>It was when pondering this and some other information I had
>read on the subject that it occurred to me that adhesion is the
>main reason for the difference in tractive effort between these
>engines.
>
>I can't comment much about the NR class because I don't have much data
>available for them but with the 81s and 82s have a very high
>adhesive ability. The 82 class because it weighs more has more
>adhesive weight and therefore can provide more tractive effort.
>
>Traction motor heating is still a problem however because as the
>speed falls off Back EMF falls and therefore traction motor currents
>rise dramatically. An example from memory is an 81 class which
>at around 20 kph has about 900 amps of traction motor current.
>If the speed drops to 15 kph the current rises to about 1100
>amps and the engine is in the time limited load range. If the
>engine was able to continue to slow down without losing adhesion
>it will either have an Alternator over current or overheat the
>traction motors and have a ground relay at the very least.
>
>The 82 class produces similar currents ,although the traction
>motors are slightly higher geared. If the loading was increased
>to take advantage of the higher tractive effort then the speed
>will fall below that of an 81 and the traction motor currents
>would be considerably higher than that of an 81 class.
>The continuos current rating for the Main alternator on an 82
>class is 7020 amps. Thus as its traction motors are in parallel
>this gives 1170 max available to the traction motors. So as you
>can see from this somewhere just below 15 kph the available
>current from the Alternator will be exceeded and the unit will
>have a Alternator over current and shed the load.
>
>When next I have a look at an 82 class loadmeter I will check to
>see at what current the time de-rating starts.
>
>--
>
>Pope
>
>Alias John MacCallum
>
>remove MY from MYlisp to get the real email address.

John, for my information and of others, what is the gear ratio of the 82 and
90 classes, their maximum speed,  their maximum continuous rating, and their
maximum rating.
If I am not mistaken, I think they both have the D87BTR traction motors, and
AR11 alternators as does the DL class?

It seems that the 82 class is the best performer for a 3000 hp locomotive,
bar possibly the C class as they were heavy monsters .

The C class lacked super-series, but still having IDAC.  The C class had a
59:18 gear ratio giving them at best a theoretical maximum speed of
145km/h(I know that the manuals always show a lower speed)- ideal for a fast
heavy passenger train on decent track.

One question that I can never find an answer to, is why weren't the DLs ever
considered by NRC for GSR passenger train working?
They have a 153 km/h maximum speed(faster than a BL), weigh 118 tonnes(the
same as an N class), have a high rated  traction motor(much higher than an
NR or EL), and have super-series wheel slip control.  Granted that a single
DL would be hard pushed to lift the IP over the Blue Mountains, they would
be ideal elsewhere.  Instead they have been literally shafted.  They only
ever lead on the Shellharbour stone trains, and  some cases are mothballed
at Islington SA.

If GSR might be concerned about the ability to turn DLs at Melbourne(or even
Sydney or Perth), then why are they considering using ELs for the Overland,
so then why speculate on spending  money on rebuilding ??  But probably the
reasoning behind it all is that  the hire rate for an EL from CFCL, is lower
than that for a DL or BL hire from the NRC.

regards, GF