Allen Nugent writes:
>Dear Listers,
>I have a 2-year old Lucas alternator on my TR7 Sprint. It has been
repaired
>no fewer than 3 times (rectifier, then brushes, then bearing)!
>Now I find that with the lights on, I run hotter (the temp gauge goes to a
>bit past 3/8 of the range, whereas without lights it sits at about 1/4
even
>on hot days). The alternator certainly qualifies as "the usual suspect",
but
>the battery terminals show 14 V at idle, whether the lights are on or off,
>and the idle rpm goes down only a fraction with the lights on. Is this a
>lousy test for an alternator?
>Alternatively, could this be caused by a partial short (low-resistance
>link?) in the light circuit? (But then, the above tests should have
revealed
>something!)
>I'm about ready to test the survivability of Lucas alternators to repeated
>blows from a large crowbar.
>Any suggestions from you electrical wizards out there?
>Allen Nugent
>Graduate School of Biomedical Engineering
>University of New South Wales
>Sydney 2052 Australia
Allen,
My guess is that the temp doesn't change at all. I'll bet that the temp
and the fuel both raise when the lights are on. Also, the headlights
are not required, only the running lights. More specifically, the dash
lights. If this is so, check for a bad ground to the dashboard. A dirty
ground will cause an undesirable voltage differential between the ground
connection to the voltage stabilizer and the real ground.
Good luck
Dave Massey, Electrical Engineer, Foster's drinker
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