> Main reason was that the board supply (battery) can change
> from 12..14V based
> on the revs of the alternator/dynamo, and this showed in things like
> temperature reading etc.
Only when using voltage-sensitive gauges. It's not difficult to build a
gauge that effectively compares the current through the sender with the
current through a known resistor; making it relatively insensitive to
changes in supply voltage. However, such gauges are relatively complicated
internally. (see Barney Gaylord's excellent series on the MGA fuel gauge at
http://mgaguru.com/mgtech/electric/fg_01.htm )
The introduction of the "voltage stabilizer" was an attempt to cut costs by
using a much simpler meter movement combined with the relatively simple
external stabilizer that could service multiple gauges.
> With the rise of the alternator (with a stabilzed 14.0V
> output)
Early Lucas alternators were only slightly better at maintaining voltage at
idle than the old DC generator. They still did not reach rated output until
well above idle (3000 rpm) and the rated output was still somewhat marginal
IMO. And the regulated voltage varied with temperature.
> in the old days, drivers
> probably didn't
> care they can use the temp gauge as an (very) averaging rev
> counter.
In the case of the TR3, the temperature gauge is mechanical and so reads
correctly even with no voltage at all.
<G>
Randall
56 TR3 TS13571L current project
59 TR3A TS39781LO (now totaled :(
71 Stag LE1473L awaiting engine rebuild
71 Stag LE2013LBW awaiting (manual) gearbox rebuild
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