TM 10-5410-228-24
e.
Calibration/Adjustment (Refer to Figure 2-21)
Once all components of the EPG system are installed, calibration/adjustment of this system is
accomplished by the EPG control unit (3). Remove EPG control unit cover by loosening four captive
screws (1).
The EPG control unit has two switch selections (S1 and S2), and four potentiometer adjustments
(DROOP, I, GAIN, and SPEED) provided on its front panel.
(1)
Switch Selections
(a)
Set S1 to OFF.
(b)
Set S2 to OFF.
(2)
Potentiometer Adjustments (System Calibration)
(a)
Set DROOP to 0.
(b)
Set I to 6 marks from zero.
(c)
Set GAIN to 5 marks from zero.
(3)
Start engine.
(4)
Set EPG switch to ON position.
(5)
Adjust SPEED potentiometer on the EPG control unit until the engine is operating at desired
engine RPM (approximately 1,475 RPM). Clockwise increases engine RPM.
(6)
If engine RPM is unstable, adjust I and GAIN settings as described in steps 7 through 11 until
engine RPM is stable, otherwise skip to step 12.
(7)
Turn GAIN clockwise slowly until actuator lever oscillates.
(8)
Turn GAIN setting counterclockwise until actuator lever is stable.
(9)
Upset lever by hand.
(10) If lever oscillates one to three times and stops, setting is correct (on warm engine). If engine is
cold, three to five times is acceptable.
(11) Reduce GAIN setting counterclockwise one division. Turn I adjustment fully clockwise while
observing actuator lever. If lever does not become unstable, upset it by hand. When lever slowly
oscillates, turn I adjustment counterclockwise slowly until lever is stable. Upset lever again; it
should oscillate one to three times and become stable for optimum response (three to five times
if engine is cold).
(12) Refer to subparagraph 2.14.5.d., steps 1 through 8, to check NBC fan speed.
(13) Install EPG control unit cover (2) by tightening four captive screws (1).
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