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Alternator Circuits

TECH TIPS
ALTERNATOR CIRCUITS
COMMON MARINE ALTERNATOR CIRCUITS
Many alternators require ignition voltage to initiate charging. You must verify that all required connections are connected
to the proper terminal and have the correct voltage in order for the alternator to operate properly. Below you will find
the most common alternator circuits used on marine applications.
EARLY MOTOROLA STYLE
FITS WESTERBEKE AND OTHERS
GROUND
B-
IGNITION +
LATE MANDO STYLE
FITS MERCRUISER AND OTHERS
B- GROUND
B+ OUTPUT
DELCO STYLE
FITS MERCRUISER & OMC
RED B+
BATTERY
SENSE
B+
OUTPUT
BLACK
GROUND B-
DELCO SELF EXCITING STYLE
FITS MERCRUISER AND OMC
B- GROUND
B+
BATTERY
OUTPUT
BATTERY -
GROUND
W
TACHOMETER
TERMINAL
D+ OR 61
INDICATOR LIGHT
B+
BATTERY
OUTPUT
VALEO/PARIS RHONE
FITS VOLVO PENTA
RED
IGNITION +
AUX NOT USED
B- GROUND
B+
OUTPUT
EARLY PRESTOLITE STYLE
FITS OMC
S
L2
INDICATOR
LIGHT
P
AC TAP
TACHOMETER
TERMINAL
LATE MOTOROLA/PRESTOLITE STYLE
FITS MERCRUISER & OMC
B+
OUTPUT
D+ INDICATOR
LIGHT
(NOT USED)
GREEN
or YELLOW
FIELD
VOLTAGE
REG
(SENSE)
RED B+
BATTERY
SENSE
(EXC)
PURPLE or
BLACK
IGNITION +
(EXC)
PURPLE or BLACK
WIRE IGNITION TERMINAL
PURPLE or
BLACK
IGNITION +
RED
WIRE BATTERY
+SENSE
B
BATTERY +
OUTPUT
LATE MOTOROLA/PRESTOLITE STYLE
FITS U.S. MARINE
B+
BATTERY
OUTPUT
(EXC)
IGNITION +
AC TAP
TACHOMETER TERMINAL
D+
INDICATOR
LIGHT
AC TAP
TACHOMETER TERMINAL
(NOT USED)
B-
GROUND
B-
GROUND
E GROUND
B-