TM 5-3825-213-35
volts. If the voltage drops when the
adjustable resistor.
Operate
full load is applied, turn the contact
under these conditions for 30
screw assembly (22) counterclockwise,
minutes.
apply a load of 100 amperes instan-
(4)
Preliminary voltage adjustment.
taneously, and check the voltage. If
(a) With the generator operating at 1,000
the voltage rises when a full load is
rpm, turn the adjusting knob of the 5-
applied, turn the contact screw
ohm adjustable resistor assembly
assembly clockwise, apply a load 100
clockwise. Turn the contact screw
amperes instantaneously, and check
assembly (22, fig. 1) clockwise until a
the voltage. Repeat the procedure
stable voltage is reached. As the
until voltage remains at 28 0.5 volts
screw is turned in, the voltage will rise,
under both battery ind full load
then drop, and then start to rise again.
conditions.
Proper point of adjustment is just
(e) Increase the alternating current
before the voltage starts to rise the
generator speed to 6,000 rpm and
second time. Vary the load from the
apply a load of 100 amperes
battery load to full load (100 amperes);
instantaneously.
After applying
voltage should remain about the same.
several loads of 100 amperes
(b) Remove the end plate (27, fig. 1) and
instantaneously, the voltage should not
loosen screw (32). Adjust the voltage
rise or drop more than 0.5 volts. If the
regulator to 26.5 volts by turning the
voltage drops more than 0.5 volts, turn
coil core (35). If the voltage is high,
the contact screw assembly (22)
turn the coil core clockwise; if the
counterclockwise and apply a load of
voltage is low, turn the coil core
100 amperes instantaneously. Check
counterclockwise. Turn the adjusting
the voltage. If the voltage varies more
knob of the 5-ohm adjustable resistor
than 0.5 volts, turn the contact screw
assembly
from
its
completely
assembly clockwise and apply a load
counterclockwise position (minimum
of 100 amperes instantaneously.
resistance) to its completely clockwise
Repeat the procedure until the voltage
position (maximum resistance). The
remains at 28 0.5 volts under both
voltage range should be from 25 to 30
battery and full load conditions.
volts. Tighten the screw to secure the
(f) Reduce
the
alternating
current
coil.
generator speed to 3,200 rpm and
Note
apply a load of 100 amperes
When the regulator is in proper
instantaneously several times. With
battery load only, voltage should now
adjustment, point marks on the coil
read 28 0.2 volts.
core (35) and coil pot end plate (31)
(5)
Final voltage adjustment.
should not be more than one-eighth
(a) Operate the generator at a speed of
of a turn apart.
2,600 rpm under a 100 ampere load.
Set the generator voltage to 28 volts
(c)
Reduce the alternator speed until
by means of the 5-ohm adjustable
regulator voltage is 26.4 to 26.6 volts,
resistor assembly. Apply a load of 100
and then measure the alternator field
amperes instantaneously and see that
current and carbon pile voltage. To
the voltage has remained constant.
measure the carbon pile voltage,
Increase the generator speed to 2,000
(d)
connect a voltmeter across B and C
rpm and apply a full load of 100
pins of the 5 cable receptacle
amperes.
The generator regulator
assembly. Divide the carbon pile
voltage should remain at 28 0.5
129