Car Audio, auto alternator Voltage Regulators & High Output Alternators

When you upgrade your existing alternator you never need to upgrade your
voltage regulator. When upgrading to a high output alternator you rarely need
to change your voltage regulator. The voltage regulator controls the alternators
output by sending power to the rotor (field). The rotor spins inside of the stator,
the reaction between the two is how power is created. The voltage regulator
senses the battery voltage, if the battery needs more power the voltage regulator
sends power to the rotor coil causing it to become an electro magnet. If the
regulator senses that the battery or system needs a lot of power it sends maximum
voltage to the rotor making it a big electro magnet thus causing the alternator to
produce maximum power. If the regulator senses a small need at the battery it will
send minimal power to the rotor causing the alternator to produce little. Never
does the alternators amperage go thought the voltage regulator. The area of
concern when changing to a high output alternator is the amperage draw of the
rotor. The voltage regulator does have a field amperage rating and because it
has direct contact with the rotor you must be concerned with the amperage draw
of the rotor. If the amperage draw of the rotor is greater than the rating for the
voltage regulator the regulator will fail.

Randy