Re: Engine Voltage

[mauried@tpg.com.au (Maurie Daly)]

On Tue, 26 Sep 2000 20:36:29 +1100, "Deano" <dsma@pigpond.com> wrote:

>I went for a spin in an 81 class (Goulburn-Wollongong and return) the other
>day and being curious was wondering if anyone can fill me in on the
>electrics. I noted the max amps was up to 1200 with a continuous figure
>somewhere near 800. I understand these locos produce about 2400kw which at
>1200 amps would equate to 2000 volts DC. A voltage this high would seem to
>carry a significant risk of arcing and I was wondering if this really is a
>problem or have I got the numbers wrong. I learned from the driver that the
>engine is connected to an AC generator which is then rectified to a DC
>voltage but he was not sure what it was. All in all it was a sensational
>experience and the escarpment was nothing short of spectacular in either
>direction. I have some electrical qualifications and am just curious, was
>wondering if anyone is familiar with the numbers applicable to these locos.
>regards Deano
>
>
>
81s have an AR16 alternator and the traction motors are parallel
connected.
This means that the total traction motor current as indicated on the
load meter is multiplied by 6 ,(6 traction motors).
The nominal output of the alternator is around 600 volts , but varies
with speed.(drops as the speed drops ,particularily when the speed
gets below 15 km/h ).

81s are transitionless (thanks to solid state power control) , but
some of the older locos provide for switching of the traction motors
into various combinations like series - parallel.
In these cases you need to know the motor combinations in order to
work out the total load current.

Some of the Vline Gs have only an AR11 alternator ,and I think that
these locos still do have switched transition for the motors,anyone
know for sure ??

MD