TM 5-3810-307-24-1-2
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If reading is higher than 31 volts on 24-volt
3. Reconnect negative battery cable at battery.
system, refer to section on "High Voltage
Output".
CAUTION
When a 12-volt carbon pile load test
9. Turn carbon pile load on and adjust to obtain
is used to diagnose a 24-volt system,
maximum generator output on ammeter
attach load test only to 12-volt
without allowing voltage at battery positive
potential in battery pack. Attaching a
terminal to drop below 25 volts on 24-volt
12-volt load test to a 24-volt potential
system. Record maximum ampere output.
will damage the load test.
With generator still running at maximum
output, check and record voltage drop in
4. With load turned off, attach carbon pile load
ground circuit between generator housing
test across battery.
and battery negative terminal. Turn carbon
pile load off.
5. Attach voltmeter negative to grounded
negative battery terminal. Leave positive
Maximum ampere output should be within 15
meter lead open for checks at various points.
amps of output rating stamped next to part
number on generator drive end (DE) frame, or as
6. Check and record voltage at battery positive
listed in Specifications section of this manual.
terminal. For multi-battery systems, check
Voltage drop should be 0.5 volts or less on a 24-
positive voltage of battery set connected as if
volt system.
in battery charging mode.
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If ground circuit voltage drop is over 0.5 volts
on 24-volt system, clean and tighten all ground
7. With all system electrical loads off, start
circuit connections. If this does not correct
engine and run at moderate speed (rpm).
excessive voltage drop, check ground circuit
cables for improper sizing or high resistance
8. Recheck voltage at battery positive terminal.
conditions. Correct as necessary.
Voltage should be higher than previous reading,
but below 31 volts on 24-volt system.
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If within 15 amps of rating, generator is good.
Look elsewhere for cause of problem.
-
If reading is lower than previous reading
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If more than 15 amps below rating, repair or
(step 6), refer to section on "No Output".
replace generator.
Figure 6. Rated Output Check
D-8 Change-1
