RE: Boosters/Slugs

["Melanie J. Dennis" <meld.asg@netspeed.com.au>]

Aus loco discussion mailing list

Hi Steve   Some Q & A for you:

>>>Thanks Melanie.  You've answered a question that's been in my mind for a
while, namely did later  12 cylinder EEs (12CSVT Mk II & III engines) have
the generator/alternator current capacity to operate with a slug, and so
better utilize their "excess" power at lower speeds.<<<

With the YS proposal, capacity of the alternator would have been OK (subject to test confirmation).  With the ZS proposal, things would have been far more marginal and more stringent tests were recommended to verify the alternator capacity - don't know how far they actually went.  Will ask some more questions when (ever) I get back to Tassie.

>>>Had the YS idea been pursued, would the Z's equipped to work with them also
have required larger auxiliary generators?  AFAIK, the Z's and ZA's, like
many late EE designs, had all-shaft driven auxiliaries including TM blowers,
and so very likely a quite small (around 10 kW) auxiliary generator.  The YS
slug would necessarily have had motor-driven TM blowers (and I'm guessing
that these would have been original Y equipment, with +/-110 volt motors).
Unless the blowers could be powered from the traction circuit (and I don't
know if this is feasible) then they'd have to be powered at 110 V from the Z
battery/control/auxiliary circuit.  Each blower would probably draw about 10
kW, give or take.  So even one YS blower powered from an adjacent Z might
strain the auxiliary electrical system.<<<

To quote the discussion paper that was circulated:  "The ZS slug is a little more complex than the YS as provision has to be made for electric blowers."  From this, I assume that the YS, because it was only cut in when the system was at Full Field may not have required blowers for short duration operation - hope the traction motor insulation is in good condition!
Nothing more was said regarding this aspect.  All traction motors (loco and slug) were rated at 200hp for their calculations.

The ZS proposal was interesting.  It postulated operation with either a single ZA / ZB or in a ZA / ZB + ZS slug + ZC trio where the ZA / ZB were rated at 2000hp and powered 4 traction motors of the slug whilst the trailing ZC was 1600hp and fed two slug traction motors.  The configurations calculated were as follows:

ZA or ZB + YS + ZA or ZB	Total load 1540t (up 28%)

ZA or ZB + YS 	  Total load 940t (up 56%)

ZA or ZB + ZS 	  Total load 1100t (up 84%)

ZA or ZB + ZS + ZC	Total load 1500t (up 45%)

Despite the YS proposal being favoured, and the ready availability of eight Y class (75% of which were redundant because of vacuum brakes), the whole idea quietly died.

Melanie Dennis
Australian Steam Group
meld.asg@netspeed.com.au

-----Original Message-----
From:	Steve Palmano [SMTP:steve719@GTE.net]
Sent:	Thursday, 24 February, 2000 10:31 AM
To:	Aus loco discussion mailing list
Subject:	Re: Boosters/Slugs (Was RE: BU1)

Aus loco discussion mailing list


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