C.E. Niehoff & Co. N1387 Alternator/EPM Operating Reference Card User Manual
Page 2
N3225 LEDs COLOR
N3225 STATUS
TABLE 2 – N3225 Regulator LEDs Diagnostics
Regulator is not energized. Measure IGN terminal voltage.
If voltage is above 21 V, regulator is defective.
Off (Clear)
Respective system voltage is below regulated setting or is
processing soft start (20-second delay).
Steady
AMBER
Respective system voltage is reading high voltage.
Flashing
AMBER
(either 28 V or 14 V)
GREEN
Normal operation (respective system voltage is at regulated
setting)
Alternator is shut down and is not producing power for either
voltage. 28 V side trips after 2 seconds of reading voltage
above 32 V. 14 V side trips after 2 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 9 of Troubleshooting
Guide for 28V systems, Chart 4 for 14 V systems.
EPM LED COLOR
EPM STATUS
TABLE 3 – EPM LED Diagnostics
EPM is not energized or EPM is defective.
Off (Clear)
Flashing GREEN
Steady
EPM has connected the batteries during start-up and has
prevented automatic disconnection for 3 minutes after vehicle
shuts down when only vehicle battery-connect button is
pressed.
Normal operation (batteries are connected to the system and
engine is running)
GREEN
AMBER
(either 28 V or 14 V
with the other LED
off)
GREEN
(both flashing once
every 5 sec.)
Regulator is energized, but waiting for AC signal from
alternator.
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