alternator HP

[mark kibort <mkibort@xxxxxxxxxxxxxx>]

My responses to Dave below his:

The engine always spins the alternator; the alternator is always tied int=
o
the =

electrical system (basically in parallel across the battery).  The
alternator =

generally maintains a constant voltage of 12-14 volts, which is higher th=
an
the =

battery voltage.  As long as that is so, the battery plays no significant=

role.
As the electrical load increases, the alternator must generate more curre=
nt
to =

maintain 12-14 volts.  In generating more current, the magnetic forces in=

the a
lternator become much greater, causing the engine to have to work harder =
to
turn =

it.  When there is no current draw, the alternator is real easy for the
engine =

to turn; when there is a lot of current draw, the alternator takes severa=
l =

horsepower to turn. =

>>>>>>>>>>>>>>>>>>>>Yes,  your explanation is basically right.  However, =

if under full load, meaning the battery voltage is very  low .  (the lowe=
r
it
becomes , the more load on the alternator, the more current produced.
Keep in mind , the maximum power that  the alternator could produce is
usually its rated  90 to 120 amps.  at a  maximum that would be about =

2hp.   We did tests with and without the battery with the eRAM on the dyn=
o
. It draws =

30 amps and kicks down the voltage of the elctrical system from
14 volts to about 12.5 then after a few seconds, it creeps up to 13..2 an=
d
stablizes there.
the dyno runs with and without a battery were so small that we couldnt se=
e
a difference.
(looked like a 1 hp gain but it was scattered throughout the curve.)


Am I wrong?
Can someone explain precisely how the alternator is operated by the car?
Is there a voltage "thermostat" that kicks on and off the alternator?
>>>>>>>>>I think you gave a good explanation  of the charging system. at
least as much as we all need to know.   =


Mark

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