C.E. Niehoff & Co. N1313 Troubleshooting Guides - Manual (Page 4)

Page 4
TG16F
Section C: Advanced Troubleshooting
N3222 Regulator
DESCRIPTION AND OPERATION
N3222 Regulator with OVCO is attached directly to
the outside of alternator. Regulator setpoint has flat
temperature compensation. Voltage setpoint is 28.0
±1.0 V and 14.0 ±0.5.
Main diagnostic feature of regulators consists of two
tricolored (red, amber, green) LEDs located on the
side of the regulator. One LED indicates 28 V system
performance, the other LED indicates 14 V system
performance. The two LEDs work independently of
each other. See Table 2 for diagnostic features and
LED explanations.
OVCO (overvoltage cutout) will trip at any of the
following conditions:
• 14 V side trips at voltage
higher than regulator
setpoint that exists longer than 3 seconds of reading
voltage above 16 V. OVCO feature detects overvoltage
and reacts by disabling the alternator field circuit.
This turns off alternator (14 V LED is steady RED
light). OVCO circuit will reset by either:
— Restarting engine (regulator regains control of
alternator output voltage) OR
— System voltage falling below 11 V. OVCO will
automatically reset.
• 28 V side trips at voltage higher than regulator
setpoint that exists longer than 3 seconds of reading
voltage above 32 V. OVCO feature detects overvoltage
and reacts by disabling the alternator field circuit.
This turns off alternator (28 V LED is steady RED
light). OVCO circuit will reset by either:
— Restarting engine (regulator regains control of
alternator output voltage) OR
— System voltage falling below 22 V.
Troubleshooting
Shut down vehicle and restart engine. If alternator func-
tions normally after restart, a “no output condition” was
normal response of voltage regulator to overvoltage con-
dition. Inspect condition of electrical system, including
loose battery cables, both positive and negative. If bat-
tery disconnects from system, it could cause overvoltage
condition in electrical system, causing OVCO circuit to
trip.
If you have reset alternator once, and electrical system
returns to normal charge voltage condition, there may
have been a one time, overvoltage spike that caused
OVCO circuit to trip.
N3039 only: If OVCO circuit repeats cutout a second
time in short succession and shuts off alternator F–
circuit, try third restart. If OVCO circuit repeats cutout,
go to Chart 3, page 7.
N3222 only: If OVCO circuit repeats cutout a second
time in short succession and shuts off alternator field
circuit, try third restart. If OVCO circuit repeats cutout
a third time, check color of LED while engine is running
and go to Chart 3a or 3b, page 7.
LED COLOR STATUS
TABLE 2 – N3222 Regulator LED Operation Modes
Regulator is not energized. Measure E terminal voltage. If voltage above 21 V, regulator is defective. OFF
Respective system voltage is at regulated setting and operating under control.
Respective system voltage is below regulated setting. Alternator is not producing power or circuit
is overloaded. See Chart 1 on page 5 for 28 V systems, Chart 2 on page 6 for 14 V systems.
Respective system voltage is above regulated setting. This may occur intermittently with voltage
transients or with system faults.
FLASHING
Green
Amber
STEADY
Red Alternator is shut down and is not producing power for either voltage. 28 V side trips after
3 seconds of reading voltage above 32 V. 14 V side trips after 3 seconds of reading voltage above
16 V. Regulator remains in this mode until reset by restarting engine or if system voltage drops
below 22 V or 11 V, respectively. See Chart 3a or 3b on page 7.
Red