Onan MJA Series Service Manual page 60

~8
GOVERNOR SYS'l'EM
3.4.:t MA.lNTENANCE
Per~odically
clean and check for wear. Do not lubricate plastic type
socket ba 11 joints. Use lubricating graphite on other jOints.
3.4.2 ADJUSTlV1ENTS
Both the gO\,(i~rned speed and the governor sensitivity can be adjusted
with the stud and nut on the front of the engine air housing.
3.4.2.1 Speed Adjustment. - To adjust the engine's governed
hold the governor spring stud in position and adjust the governor spring
nut with a wrench. For accurate speed adjustment, use a reed type
frequency meter on the generator's ac output. A mechanicai tachome­
ter can be used, but this usually isn't as accurate. Set speed within ­
the range shown in Fig 3. 4. B .
3.4.2.2 Sensitivity Adjustment. - To adjust the governor sensitivity,
turn the governor spring stud; counterclockwise gives more sensitivity,
-c
less speed drop.
If
the governor is too sensitive, a hunting condi­
tion occurs (alternate increasing and decreasing speed). Adjust for
range in Fig 3.4.B. After sensitivity adjustment, the speed will re ­
quire readjustment.
If
the governor is either too sensitive or not sensitive enough and can't
be adjusted with the stud the sensitivity can be coarsely adjusted by
moving the point where the spring attaches to the governor arm. Mov ­
ing this pOint farther from the governor shaft decreases the governor's
sensitiyHy .
Preferred
freg. spread
Freq. Ma."'!;. freq. Min.
Ma::x.
NoIllinal
preferred spread-no
Model freg.
allowablE allowable
Plant.
I
output
-no load to
(cps)
load to full
freq. - no load
freq.
(cps) ­
full load
to full load load (cps)
E.e ­
61 .. 59 3 1.5
volying
63 59 60
(45)
(90) (1770) (1830 .. 1770)
(18S0)
3­
48 51.. 49 52
1
I
I
Arm­
50
ature
(1440) (1530-1470)
(1560) (90) {3~)
2
E.e""
_,;.:,,6~
..
59 3
64 57
.,:~
60
(60)
valying
(90)
(1920)
(17'Z~9r.
\
fl8\3,Q~1770)
4f[ -",
;;"~;;,~[:i 1':.<4 ~
3 1
54
Field
50
(1410)
;(:jl~~O .. 1{7G)
(90)
(30)
(1620)
...
~:'
".:
Numbers
in
pal'e~:es~§ ar~~:p1ant
speed
in
rpm.
FIq.
3_.4. B -
FREQ1lENeYAND
SPEED TABLE
!
4
' 1
,~)