C.E. Niehoff & Co. C622 Troubleshooting Guides - Manual (Page 4)

Page 4
TG0011A
A2-307 Regulator
DESCRIPTION AND OPERATION
A2-307 Regulator with OVCO is attached directly to
the outside of alternator. Set point of temperature
compensation regulator is 82.0 V.
Main diagnostic feature of A2-307 regulator 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 84 V
system performance. The two LEDs work indepen-
dently of each other, not in combination with each
other. See Table 2 for diagnostic features and LED
explanations.
OVCO (overvoltage cutout) will trip at any of the
following conditions:
• 28 V side trips at voltage
higher than regulator
setpoint that exists longer than 2 seconds of
reading voltage above 32 V. OVCO feature detects
high voltage and reacts by signaling relay in F+
alternator circuit to open. This turns off alterna-
tor (28 V LED is steady RED light). Restarting
engine resets OVCO circuit. Regulator regains
control of alternator output voltage.
• 84 V side trips at voltage higher than regulator
setpoint that exists longer than 2 seconds of
reading voltage above 85 V. OVCO feature detects
high voltage and reacts by signaling relay in F+
alternator circuit to open. This turns off alterna-
tor (84 V LED is steady RED light). Restarting
engine resets OVCO circuit. Regulator regains
control of alternator output voltage.
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
“high voltage” condition. Inspect condition of electri-
cal system, including loose battery cables, both
positive and negative. If battery disconnects from
system, it could cause “high 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, high voltage spike,
causing OVCO circuit to trip.
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 a third
time, check color of LED while engine is running.
28 V RED LED - go to Chart 1, page 5.
84 V RED LED - go to Chart 2, page 5.
LED COLOR STATUS
TABLE 2 – A2-307 Regulator Diagnostics
Regulator is not energized. Measure E terminal voltage. If voltage above 21 V, regulator is
defective. OFF
Section 3: Advanced Troubleshooting
Respective system voltage is at regulated setting and operating under control.
Respective system voltage is below regulated setting. Alernator is not producing power or circuit
is overloaded.
Respective system voltage is above regulated setting. This may occur intermittently with voltage
transients or with system faults.
FLASHING ( once per second
for respective system voltage)
Green
Amber
STEADY
Amber (84 V LED Only) Alternator is producing only 28 V output current. This will occur if 84 V batteries are discon-
nected. Regulator remains in this mode until reset by restarting engine.
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. 84 V side trips after 2 seconds of reading voltage above
85 V. Regulator remains in this mode until reset by restarting engine.
FAST FLASHING RED
(at least two times per second
for respective system voltage)
Indicates regulator redundant control is lost. Service as soon as possible for alternator,
regulator or wiring fault. High side voltage will continue to produce 84 V, but low voltage side
will default to 26 V regulation to alert operator of control malfunction. Regulator remains in
this mode until reset by restarting engine. See Chart 1, page 5.
HIGH VOLTAGE. Use extreme
caution when working around 84 V
system. Severe personal injury or death will result from contact.
DANGER
Red
Red