C.E. Niehoff & Co. N1601/N1602/N1603/N1604 Troubleshooting Guides - Manual (Page 2)

Page 2 TG29D
Section A: Wiring Diagrams
CEN N1601, N1602, N1603, N1604
Alternator and Regulator Description
and Operation
The alternators listed below are self-rectifying. All wind-
ings and current-transmitting components are non-
moving, so there are no brushes or slip rings to wear
out. Energize switch activates regulator. Field coil is
then energized.
• N1601
28 V 400 A
• N1602 28 V 400 A with optional 28 V/ 14 V
(50 A maximum on 14 V)
• N1603 28 V 450 A
• N1604 28 V 400 A
N3107 regulator used on some N1601, N1603, and
N1604 alternators maintains alternator output voltage
at regulated setting as vehicle electrical loads are
switched on and off. Alternator output current is self-
limiting and will not exceed rated capacity of alternator.
The regulator has:
• an AC terminal to provide optional AC voltage
output tap.
• overvoltage cutout (OVCO). Regulators with OVCO
(overvoltage cutout) will trip at vehicle electrical
system voltages above 32 volts that exist longer than
3 seconds. OVCO feature detects high voltage and
reacts by signaling relay in field control circuit to
open. This turns off alternator. Restarting engine
resets OVCO circuit.
The following regulators receive energize signal after
engine is running:
• N3118—used on some N1602 alternators
•
N3211—used on some N1601 and N1603 alternators
• N3223—used on some N1602 alternators
• N3236—used on some N1604 alternators
• N3237—used on some N1602 and N1603 alternators
• N3245—used on some N1602 and N1603 alternators
Regulator monitors alternator rotation and provides
field current only when it detects alternator shaft rotat-
ing at suitable speed. After regulator detects alternator
rotation, it gradually applies field current, preventing an
abrupt mechanical load on accessory drive system. The
soft start may take up to 10 seconds at full electrical
load. These regulators:
• are negative temperature compensated. Setpoints
are 28.0 ± 0.2 V (and on N3118 and N3223, 14.0 ±
0.2 V. See below.) at 75F. N3237 and N3245 regula-
tors are negative temperature compensated accord-
ing to switch-selected battery type. Customer selects
position per application.
• provide 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
3 seconds. OVCO feature detects high voltage and
signals the field circuit to open, turning off alterna-
tor. Restarting engine resets OVCO circuit.
• maintain alternator output voltage at regulated
settings as vehicle electrical loads are switched
on and off.
N3118 and N3223 regulators can be used in single
28 V or dual voltage applications. The regulators:
• allow single-voltage operation (28 V only). 14 V
single voltage application is not available with
these regulators.
• provide optional 28 V/14 V output only from the
regulator when phase cable from alternator is
connected to regulator.