TM 5-3810-307-24-1-2
If voltage is lower than reading previously
Residual magnetism in the rotor is
-
recorded with engine stopped, there is no
sometimes lost during servicing of the
generator output. Proceed to section on "No
generator. If the generator has no "R" or
Output."
"RELAY" terminal, proceed to step 2. If the
generator has an "R" terminal, the rotor can
-
If voltage is higher than previous reading with
be remagnetized without removing generator
engine stopped, generator output is present.
from application. To remagnetize rotor, make
Proceed to section on "Rated Output Check".
sure the normal connections are made to the
generator BAT terminal and to the ground
2.
If battery is overcharged (as evidenced by
circuit. Disconnect the wiring harness from
excessive water use or electrolyte spewing
the "R" terminal. Momentarily connect a
from battery vents), light bulbs or other
jumper lead from battery positive to the
electrical equipment have shortened life due
generator "R" terminal. This will cause field
to suspected high system voltage, or system
current to momentarily flow through the rotor
voltmeter reads above normal range:
in the proper direction and restore
magnetism. Reconnect wiring harness to "R"
With fully charged battery, engine running at
terminal, then recheck generator for output.
moderate speed and all electrical loads off,
use voltmeter to check voltage at battery
2.
If no conditions have been found that might
terminals.
prevent the generator from turning on,
remove and replace the generator.
For a 24-volt system, readings should be
stable, around 27 - 28 volts and in no case
D.
RATED OUTPUT CHECK
go above 31 volts.
TEST EQUIPMENT NEEDED:
-
One-wire system: If voltage is erratic or goes
above 31 volts on 24-volt system replace
Voltmeter
regulator as described under "Unit Repair".
Ammeter (current capability at least 15
amperes higher than generator rating)
Variable Carbon Pile Load Test
C.
NO OUTPUT
TEST EQUIPMENT NEEDED:
WARNING
Voltmeter
Failure to disconnect negative
Jumper Lead (18 ga. mm; no fuse)
battery cable at battery before
removing or attaching generator
NOTE
"BAT" terminal lead may result in an
injury. If a tool is shorted at
21-SI generators must be connected to
generator "BAT" terminal, the tool
a battery for the voltage sensing circuit
can quickly heat enough to cause a
to allow initial turn on (refer to section
skin burn.
on
Features).
When
properly
connected and system checks indicate
1.
Refer to Fig. 6 for test equipment hookups as
a "no output" condition, use the
described in following steps. If inductive
following steps to determine if the
pick-up ("clamp on") type ammeter is used,
generator requires repair:
place current clamp on generator output lead
and skip to step 4. If series ammeter is
For one-wire systems without an "I" terminal,
1.
used, disconnect negative battery cable at
battery positive voltage at the "BAT"
battery.
terminal and residual magnetism in rotor are
necessary for generator to turn on. Use
2.
Install ammeter in series with generator
voltmeter to verify that battery voltage is
"BAT" terminal.
present at "BAT" terminal. If not, locate and
correct cause of voltage loss.
