R E P A I R OF GENERATOR SET
Section I. CONTROL BOX ASSEMBLY
t h e regulator for overhaul after 1000 hours of
operating time and accomplish the following:
The control box assembly is located on the left side
(1) Check condition of contact surface of pile
of the generator set. The control box houses the
screw including both ends of the compression piece.
voltage regulator, r e v e r s e current relay, output
If blackened or pitted, clean with fine file or crocus
relay, terminal board assembly, load stud assembly
cloth. If these surfaces cannot be cleaned without
and wiring harness.
wearing through the silver plating, install a new
3-2. Voltage Regulator
part. Also inspect the threads on the pile screw.
a. Removal. Refer to figure 3-1 and remove the
( 2 ) Make sure that the surface around the
small tapped hole of the screw holders is clean.
Scrape if necessary.
(1) Back out the pile screw (5, fig. 3-2) to
(3) Discard the whole carbon pile if any of the
relieve pressure on the carbon pile.
washers are pitted, rough or broken. If in doubt,
(2) Remove the pile screw assembly (5 to 17).
install a new pile. Avoid unnecessary handling if
(3) Remove the carbon pile (18). Keep free
the pile is to be reused.
from dirt and grease on a small rod of screwdriver.
(4) Wipe the insulation tube clean. Discard if
(4) Remove the glass tube (19).
cracked or chipped.
Remove the magnet cup (39).
(5) Clean the ends of the terminal pins on
Remove the magnet plate and stop (46).
bracket if necessary with a fine file or crocus cloth
Remove the base assembly (24).
(6) Discard insulation bushings if broken,
Remove the spring rest (47).
cracked or chipped.
Pull the armature assembIy (48) out of the
(7) Discard the coil if the insulation of the
leads or coil body is damaged.
c. Cleaning. Make sure that all parts are free
(8) Discard the resistors if enamel is broken or
f r o m dust dirt, metal filling and other foreign
charred. Check the small resistor for fatigue ter-
particles. All parts should be free of grease or oil,
minal wires or broken insulation.
except for the spring (59, fig. 3-2) which has a very
( 9 ) Discard the rheostat if the winding is
thin film of oil, for corrosion resistance. This film of
damaged, if there is no contact pressure on the
oil should not be removed. Wipe insulation tube
contact arm, or if rotation is rough or uneven.
clean. No cleaning agents are required.
(10) Discard any wires with chafed or broken
d. Inspection. After 500 hours of operating time,
check the regulator performance, preferably on a
(11) Test the parts with a resistance bridge,
test bench. Adjust the pile screw if necessary. Refer
measure the resistance of the coil windings,
to test procedures (para g below). Then return the
resistors and rheostat.
r e g u l a t o r to service. I f t h e p r o p e r a d j u s t m e n t
(a) Discard any part that does not check
cannot be obtained, install a new carbon pile; oth-
within the following limits shown in table 3-1.
erwise remove the regulator for overhaul. Remove
Table 3-1. Resistance Limits
resistance in Ohms
at 25°C (77°F)
Potential winding (red and green leads)
Equalizer winding (brown and black leads)
Potential resistor (25 watts)
Stabilizing resistor (1 watt)