Chapter 3 REPAIR OF GENERATOR SET

CHAPTER 3

R E P A I R OF GENERATOR SET

Section I. CONTROL BOX ASSEMBLY

t h e regulator for overhaul after 1000 hours of

3-1. General

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

voltage regulator.

small tapped hole of the screw holders is clean.

b. Disassembly.

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.

(5)

Remove the magnet cup (39).

(5) Clean the ends of the terminal pins on

(6)

Remove the magnet plate and stop (46).

bracket if necessary with a fine file or crocus cloth

(7)

Remove the base assembly (24).

(6) Discard insulation bushings if broken,

(8)

Remove the spring rest (47).

cracked or chipped.

(9)

Pull the armature assembIy (48) out of the

(7) Discard the coil if the insulation of the

housing.

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,

insulation.

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 25C (77F)

Part

Maximum

Coil

6.0

Potential winding (red and green leads)

4.8

0.44

0.36

Equalizer winding (brown and black leads)

11.0

9.0

Rheostat

32.6

29.5

Potential resistor (25 watts)

550

450

Stabilizing resistor (1 watt)

3-1