Adjustment -706881076

TM 5-4210-233-14&P-1

5-79. APU GOVERNOR - Continued

d. Adjustment.

(1)

Adjust engine speed (rpm) by turning engine speed adjustment nut. Use screw driver to prevent

stud from turning and turn nut clockwise to increase speed, counterclockwise to decrease speed.

(2)

Sensitivity (no load to full load speed drop) is adjusted by turning the sensitivity adjusting ratchet

nut accessible through hole in side of blower housing. 'If speed drops too much when full load is

applied, turn the ratchet nut counterclockwise to increase spring tension and compensate for

reduced rpm. An over-sensitive adjustment, approaching no speed drop when load is applied may

result in a hunting condition (alternate increase and decrease in speed). Adjust for maximum

sensitivity without hunting. The use of a reed-type frequency meter will give the most accurate

results. A mechanical tachometer can be used on the generator thru stud, but this is not generally

as accurate. It should be possible to adjust for a sensitivity of less than 3 cps, and 2 cps is usually

attainable.

(3)

After adjusting speed and sensitivity, secure speed stud lock nut and replace dot button in blower

housing.

e. Follow-on Maintenance.

(1)

Install gear cover (see para 5-68).

(2)

Install APU (see para 4-207).

5-405