Table of Contents
Advertisement
OM-2040 / Operation and Maintenance Manual
90D20 / Generator Sets
(44) Check 400-Hz generator bearings. Use a stethoscope or metal sounding rod to listen for
unusual noises. If using a metal rod, place one end on the generator housing and hold the other
end near the ear. Hold the rod with three fingers and use the index finger and thumb to form a
"sounding chamber" between the rod and the ear. Do NOT allow the rod to touch the ear. Listen
for "grinding" or pounding sounds which would indicate a defective bearing. An engine noise
may be "telegraphed" to the generator and misinterpreted as a generator noise. If in doubt of
bearing service ability, send unit to be overhauled.
WARNING
3. Generator Set Adjustment
a. Generator Adjustment
The 400 Hz generator is a brushless type requiring no adjustments of any kind.
b. Generator Control Adjustments
The following items may require adjustment of some time during life of the equipment.
(1) Adjust manual voltage control, variable resistor.
The adjustment of this resistor (Ref. 1-1; 1, Fig. 8) determines the maximum generator output
voltage obtainable when using the manual control rheostat for voltage control. To adjust
maximum voltage potential, proceed as follows:
a. Loosen slider-band clamping screw.
b. Move the slide-band toward the single wire end of the resistor to increase voltage potential.
Move the band towards the double wire end (two wires connected) to decrease voltage
potential.
c. Tighten slider-band clamping screw.
(2) Adjust 400-Hz voltage regulator
When a voltage regulator is first put into service, or when output (generator-to-aircraft) cables
are changed, the regulator may require adjustment. To make these adjustments, refer to the
appropriate voltage regulator manual in Chapter 6 of this manual.
Hobart Manual TM-759 covers the magnetic-amplifier type voltage regulator, Part No.
430391C, which is used on many of the generator set specifications covered by this manual.
Hobart Manual OM-2020 covers the newer solid state voltage regulators, Part Numbers 489812
and 489812A.
c. Basic Engine Adjustments
Adjustment procedures applicable to the diesel engine are included in the Deutz Diesel Operator's
Manual, which is located in Chapter 6. Specific information for this particular engine application is
listed in Figure 4.
(1) Exhaust valve adjustment.
(2) Exhaust valve bridge adjustment.
(3) Fuel injector timing adjustment.
(4) Idle speed, speed limiting, and overspeed adjustments.
Use instructions which apply to a single weight governor. Recommended idle speed for this
application is 650 to 700 RPM.
NOTE: A stroboscope is required for engine speed test.
The limiting speed governor should be set at a speed just below the overspeed governor trip
point, or approximately 2350-2400 RPM.
February 28/94 Revised
Electric shock, moving parts, and noise can kill or injure! If a metal sounding
rod is used to detect bearing noises, exercise extreme care to avoid injury.
Chapter 2-3
Page 9
Advertisement
Table of Contents
Troubleshooting
