C.E. Niehoff & Co. N1224 Standard Troubleshooting Guides - Manual (Page 3)

Page 3
TG0045A
Section 2: Regulator Operation Modes
N3221/N3229/N3232 Regulator
DESCRIPTION AND OPERATION
N3221/N3229/N3232 Regulators with OVCO are at-
tached 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.
Once generating power, the alternator will continue
to do so, even if external energize signal is removed.
Once energize signal is removed, the alternator will
shut down approximately 5 seconds after it stops
rotating.
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 1 for diagnostic features and
LED explanations.
OVCO (overvoltage cutout) will trip at any of the fol-
lowing conditions:
• 14 V side trips at voltage
higher than regula-
tor 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 regula-
tor 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. OVCO will
automatically
reset.
TROUBLESHOOTING
Shut down vehicle and restart engine. If alternator
functions normally after restart, a “no output condi-
tion” was normal response of voltage regulator to
overvoltage condition. Inspect condition of electrical
system, including loose battery cables, both positive
and negative. If battery 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.
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.
28 V RED LED - go to Chart 3, page 7.
14 V RED LED - go to Chart 4, page 7.
LED COLOR STATUS
TABLE 1 – N3221/N3229/N3232 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 6 for 28 V systems, Chart 2 on page 7 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 3 on page 7 for 28V systems, Chart 4 for 14 V systems.
Red