P-9-TM-457-35
T.O. 35 C2-3-442-2
TM-07464A-35
TM 5-6115-457-34
reduce high feedback gain by rotating po-
(b) Before starting engine, ro-
tentiometer (R16) counterclockwise,
tate magamp bias balance adjustment po-
tentiometer R11, feedback null adjustment
( e ) To eliminate a low frequency,
potentiometer R14, feedback gain adjust-
high amplitude hunting condition, reduce
ment potentiometer R16, and frequency
frequency gain by rotating potentiometer
gain adjust potentiometer R18 on electric
R18 counterclockwise When a reduction
governor control unit to a mid-position
of frequency gain does not correct the con-
position. Then rotate load measurement
dition, increase feedback gain by rotating
gain adjustment potentiometer R15 to a
potentiometer R16 clockwise, When a
full-rotation counterclockwise position,
reduction of frequency gain and/or an in-
and the magamp bias level adjustment po-
crease in feedback gain does not eliminate
tentiometer R12 to a three-quarter-rotation
slow hunting, rotate potentiometer r R1 2
counterclockwise position.
more in a counterclockwise direction to
increase magnetic amplifier bias level.
NOTE
Should none of the above adjustments cor-
rect and stabilize the system, increase the
To determine desired rotation posi-
capacitance (non-polarized, 50 vdc, 25 mfd
tion of a potentiometer or rheostat,
to 100 mfd electrolytic) of capacitor C1
turn shaft clockwise to stop. Then
located in the governor resistor assembly
rotate shaft counterclockwise to
A6 in the precise relay box for 50/60 hertz
stop, counting the number of turns
sets or the mode II relay box for 400 hertz
between clockwise and counterclock-
sets Refer to relay box diagram figures
wise stops. Now, rotate shaft
1-16 and 1-20. Alternately change capaci-
clockwise for a given number of
tance value and repeat potentiometer R18,
turns to obtain desired rotation
R16, and R12 adjustments until the system
position.
is stabilized, thus eliminating the low fre-
(c) Start engine and observe fre-
quenc y, high amplitude hunting condition.
quenc y meter and voltmeter readings for
(f) With the engine running and
indication of fluctuation in either voltage or
frequency. Also listen to engine for sound
the system stabilized, insert test probes
of a 0-10 volt DC voltmeter in test jacks
of engine hunting. If high frequency, low
3 and 4 (test jack 4 is positive). Rotate
amplitude engine hunting is observed, pro-
frequency adjust rheostat R1 for a 60-hertz
ceed to step (d) and make the necessary
(400 hertz on 400 hertz unit) reading on the
adjustment; if low frequency, high ampli-
frequency meter. Then adjust potentiom-
tude engine hunting is observed, proceed
eter R14 for a zero voltage reading between
to step (e) and make the necessary adjust-
test jacks 3 and 4 under no load condition.
ments. If frequency and voltage outputs
are stabilized, skip steps (d) and (e), pro-
ceed to step (f) and continue with alignment
(g) Before removing the volt-
meter from test jack 3 and 4, install test
procedures.
probes from a similar voltmeter in test
jacks 1 and 2, (test jack 1 is positive) and
(d) To eliminate a high frequency,
alternately adjust potentiometer R11 and the
low amplitude hunting condition, reduce
frequency adjust rheostat to obtain a zero
magamp bias level by rotating potentiom-
voltage across test points 1 and 2, and 3
eter (R12) in a clockwise direction, and
Change 3
6-180
