C.E. Niehoff & Co. N1610 Troubleshooting Guides - Manual (Page 4)

Page 4 TG61B
Section C: Advanced Troubleshooting
N3258 Regulator
DeSCrIptION AND OperAtION
N3258 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
bicolored (amber and green) LEDs located on the side
of the regulator. One LED indicates 28 V system perfor-
mance, 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) 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 flashes AMBER).
OVCO circuit will automatically reset when:
— engine is restarted
OR
— system voltage falls below 11 V
• 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 flashes AMBER).
OVCO circuit will automatically reset when:
— engine is restarted
OR
— system voltage falls below 22 V.
Troubleshooting
Shut down vehicle and restart engine. If alternator
functions normally after restart, a “no output condition”
was normal response of voltage regulator to overvoltage
condition. Inspect condition of electrical system, includ-
ing loose battery cables, both positive and negative. If
battery disconnects from system, it could cause over-
voltage 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 and go
to Chart 3, page 7.
LED COLOR STATUS
TABLE 2 – N3258 Regulator LED Operation Modes
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. FLASHING Amber
STEADY
Green
Amber
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 over-
loaded. See Chart 1 on page 5 for 28 V systems, Chart 2 on page 6 for 14 V systems.