C.E. Niehoff & Co. N1246-1 Troubleshooting Guides - Manual (Page 2)

Page 2
TG0049A
Section 1: Wiring Diagram
CEN N1246-1 Dual Voltage Alternator
Description and Operation
N1246-1 28 V 200 A alternator with optional 28 V/
14 V (50 A maximum on 14 V) is internally rectified.
All windings and current-transmitting components
are non-moving, so there are no brushes or slip rings
to wear out.
After engine is running, remote-mounted
N3231
regulator receives energize signal. Regulator
monitors alternator rotation and provides field
current only when it detects alternator shaft rotating
at suitable speed.
After regulator detects alternator rotation, it gradually
applies field current, preventing an abrupt mechani-
cal load on accessory drive system. The soft start
may take up to 10 seconds at full electrical load.
N3231 regulator used with these units also
• is negative temperature compensated. Setpoints
are 28.0 ± 0.2 V and 14.0 ± 0.2 V at 75° F.
• provides overvoltage cutout (OVCO). Regulator will
trip OVCO when system voltage rises above 32 V
in a 28 V system (16 V in a 14 V system) for longer
than 2 seconds. OVCO feature detects high voltage
and reacts by signaling relay in F– alternator
circuit to open, turning off alternator. Restarting
engine resets OVCO circuit.
B– terminal
Figure 2 — N1246-1 Alternator with N3231 Regulator Wiring Diagram
Figure 1 — N1246-1 Alternator and
N3231 Regulator Terminals
14 V B+ terminal
28 V B+ terminal
T
T
T
D+ terminal
T
IGN terminal
T
• maintains alternator output voltage at regulated
settings as vehicle electrical loads are switched
on and off.
• can be used in single or dual voltage with these
alternators.
— Allows single-voltage operation (28 V only).
14 V is not available as a single voltage appli-
cation with this regulator.
(ADE shown)