should be exercised and the length of each exercise.
d. In addition to exercising the units, it is also
National and local codes may enter into this consid-
desirable to periodically perform an operational
eration.
test. This test is accomplished by opening the cir-
c. The procedures used for exercising the units
cuit breaker from the electric utility and verify-
will also vary from station to station. The most
ing that the necessary relays and contactors ener-
desirable condition is to use the actual load. How-
gize such that the emergency generator breaker
ever, this is not always possible and in these cases a
closes and starts the auxiliary power generating
load bank can be used. A load bank is generally a
system. Performance of the test simulates a loss of
portable set of resistors that allows a generator to
commercial power. The frequency of this test is de-
be tested under load by disconnecting the generator
pendent on the nature of the load, i.e., critical or
from the actual load and connecting it to the load
non critical, but is usually performed on a monthly
bank. In those stations that permit paralleling with
basis.
6-5
TM 5-685/NAVFAC MO-912
ROUTINE MAINTENANCE
7-1. Instructions.
station log sheets, related records, and the manu-
a. Manufacturers provide specific instructions for
facturer’s recommendations.
the use and care of each of their products. Their
(2) Checklist.
instructions are the result of wide experience ob-
(a) Values. Check valve operation.
tained under varying conditions and should be fol-
(b) Fuel injection nozzles. Check fuel injec-
lowed closely. Maintenance personnel should always
tion nozzles for secure mounting and connections
check equipment first for signs of physical damage
each time the engine is shut down. Torque down the
before performing any other checks.
nozzles according to the manufacturer’s instruc-
b. Routine maintenance instructions consist of
tions.
scheduled inspections of prime movers, generators
(c) Starting system. Check the general condi-
and exciters, and switchgear. When a need for ser-
tion of the air compressor, air lines, and valves,
vice or repair is indicated, refer to the manufactur-
when applicable. Briefly pop open the system’s
er’s literature for specific information. Service
safety valve weekly. Check for proper operation. Re-
records of the auxiliary power systems are filed in
fer to manufacturer’s instructions for details.
the installation’s engineering office.
(d) Governor alarms and instruments. Check
c. Maintenance information provided in this
operation of governor alarms and instruments. Re-
manual supplements the manufacturer’s instruc-
fer to manufacturer’s instructions‘
tions but does not supersede them. Checklists and
(e) Pressure gauges. Check pressure gauges
schedules furnished herein are intended as guides
and clean exposed indicating elements. Refer to
for operators and service personnel.
manufacturer’s instructions.
d. Since auxiliary power systems are operated
(f) Intake and exhaust systems. Check air fil-
ters and engine exhaust. A smoking exhaust indi-
I--
intermittently, the usual time frames for routine
maintenance such as weekly, monthly, quarterly,
cates incorrect adjustments. Clean air filters as nec-
annually may not apply. Accordingly, “short-term” is
essary.
used for tasks to be performed less frequently. Ex-
(g) Exhaust Lines. Clean and inspect exhaust
ceptions are noted in the manufacturer’s manual.
lines. On two-cycle engines, remove carbon from
e. Electrical systems acceptance tests are func-
exhaust ports and clean thermocouples. Refer to
tional tests to verify the proper interaction on all
manufacturer’s instructions for frequency of checks.
sensing, processing, and action electrical devices. It
(h) Evaporative cooling. Refer to manufac-
is critical that these tests be performed on standby
turer’s instructions for cooling tower maintenance.
generator power systems to ascertain the safe and
Inspect and oil fanshaft bearings, oil damper bear-
operational reliability of a system. A system must be
ings and linkage. Inspect spray nozzles; clean as
tested as a united series of devices in addition to the
necessary. Clean pump suction screen. Clean sump
testing of individual components. For systems that
pan. Inspect cooling coil. If scale has formed, circu-
include auto-start, auto-transfer, and/or auto-
late cleaning solution. Do not operate fan while
synchronizing equipment, every six months utility
cleaning coil. Check belts for condition and proper
electrical power should be removed (open main cir-
tension. Refer to manufacturer’s instructions.
cuit breaker) from a building, or part of the facility
that is supplied electrical power by commercial
(i) Fuel oil system. Clean fuel oil strainers as
power/generation combination to ascertain that the
required by operating conditions. Check the system
system will operate under abnormal conditions.
components for clean condition. Refer to manufac-
turer’s recommendations.
7-2. Prime mover maintenance.
(j) Fuel filters and centrifuges. Check fuel oil
Routine maintenance instructions for prime movers
filters and centrifuges. Check fuel oil system for
consist of short- and long-term checklists for diesel
leaks and correct as required. Refer to manufactur-
and gas turbine engines.
er’s instructions.
a. Short-term (diesels). Short-term checklist for (k) Lubricating systems. Check mechanical
diesel engines.
lubrication hourly during operation. Oil all hand
(1) General comments. Before performing any
lubrication points, following manufacturer’s in-
tasks required by the following checklist, review the
structions. Correct leaks.
7-1
TM 5-685/NAVFAC MO-912
(l) Sight-feed Lubricators. Clean sight-feed
(d) Camshaft and drive. Check and adjust
lubricating oil strainers as necessary. Check for ad-
gears and/or timing chain. Refer to manufacturer’s
equate lubricant supply.
instructions.
(m) Lubricating oil filters. Check lubricating
(e) Camshaft bearings. Inspect and adjust
oil filters. Clean and replace filter elements as nec-
camshaft bearing clearances. Refer to manufactur-
essary.
er’s instructions.
(n) Piston assembly and connecting rods. On
(f) Fuel injection nozzle inspection. A f t e r
two-cycle engines, remove upper handhole inspec-
2000 hours of use, remove and check nozzles in the
tion cover from side of engine immediately after the
test stand. Service and adjust nozzles following
engine is shut down, and inspect the piston for
manufacturer’s instruction.
proper lubrication.
(g) Fuel injection pumps. Inspect fuel injec-
(o) Cylinders and cylinder heads. Use com-
tion pumps for secure mounting, cleanliness, and
pressed air to blow out indicator connections. Clean
proper operation.
indicators and install. Refer to manufacturer’s in-
(h) Fuel injection pump inspection. Disas-
structions.
semble and recondition all injection pump nozzles
(p) Crankshaft, crankpin and main bearings.
after 2000 hours of use. Repair or replace worn or
Remove crankcase covers immediately after engine
damaged parts. Reassemble and adjust, following
is shut down. Check main and crankpin bearings for
the manufacturer’s instructions.
proper lubrication. Check bearing temperatures for
(i) Air Lines. Drain water from air lines and
excessive heat by hand-touch. Refer to manufactur-
tank monthly or as necessary. Drain valves are usu-
er’s instructions for frequency of checks.
ally located at the lowest point(s) in the air feed
(q) Gauges and instruments. Verify that
system.
gauges and instruments have up-to-date calibration
(j) Air valves. Clean air valves and reseat if
certifications. Read and record all indications of
necessary. Refer to manufacturer’s instructions.
gauges, thermometers and other instruments at
(k) Air compressor. Disassemble and over-
regular intervals as required by the operating log.
haul the air compressor and starting equipment
(r) Turbocharger. Observe every four hours
every five years based on frequency of use of the
during operation. Check for general condition and
auxiliary power plant.
signs of vibration. Evaluate vibration if present.
(l) Pressure gauge inspection. Check the date
(s) Turbocharger impeller. Check turbo-
of calibration. Verify that gauges have valid calibra-
charger impeller for accumulated dirt and axial
tion certification. Calibrate per manufacturer’s in-
endplay. Dirt may indicate faulty filtering equip-
structions as required.
ment. Clean and service according to manufactur-
(m) Governor overhaul. Overhaul the gover-
er’s instructions.
nor after 2000 hours of use or when needed as
b. Long- term (diesels). Long-term checklist for
indicated. Repair or replace worn or damaged parts.
diesel engines. Performance of checklist tasks is
Reassemble and adjust, following the manufactur-
related to frequency and extent of use of the auxil-
er’s instructions.
iary power plant.
(n) Muffler (silencer). Keep the muffler and
(1) General comments. The following tasks
waste heat equipment, boiler or heat exchange
should be performed annually, unless otherwise
clean. Accumulations of unburned lubricating oil
noted, following performance of short-term checks.
and soot or carbon are potential fire hazards. Make
(2) Checklist and schedule.
sure fuel combustion is as efficient as possible. Re-
(a) Valve inspection. Inspect exhaust valves;
fer to manufacturer’s instructions.
clean and remove carbon on two-cycle engines and
(o) Cooling systems. Inspect piping and
valves as necessary. Refer to manufacturer’s in-
valves for leaks and clean the heat exchanger. Per-
structions.
form cooling system maintenance, refer to appendix
(b) Inlet valves. . Inspect and regrind inlet and
D, herein, and manufacturer’s instructions.
exhaust valves and valve seats as necessary. Refer
(p) Cooling tower. Drain and clean cooling
to manufacturer’s instructions.
tower; clean and inspect piping, circulating pumps
(c) Valve springs and guides. Check valve
and equipment. Refer to appendix D.
spring length and tension and inspect valve stems,
(q) Cooling system service. Clean and inspect
bushings, and guides annually or after 2000 hours
entire cooling system yearly. Overhaul pumps and
of use, whichever comes first. Replace parts as nec-
recondition valves and other equipment as neces-
essary. Refer to manufacturer’s instructions.
sary. Refer to manufacturer’s instructions.
7-2
TM 5-685/NAVFAC MO-912
(r) Fuel oil tanks and lines. Drain service crankwebs for crankshaft deflection. Check journal tanks and lines. Remove water and sediment.
level and clean oil passages. Replace bearings as
Check heating coil for proper operation. Refer to necessary and adjust running clearance following appendix B. the manufacturer’s instructions.
(s) Lubricating oil cooler. Clean and inspect (ad) Turbocharger inspection. Disassemble,
lubricating oil cooler for leaks and good condition.
clean and inspect entire turbocharger following the
Clean outer surfaces more often under dusty oper-
manufacturer’s instructions and specifications.
ating conditions for more efficient cooling. Refer to
(ae) General overhaul. Overhaul diesel en-
manufacturer’s instructions.
gines and driven equipment every ten years or
(t) Crankcase. Drain crankcase semi- annu-
about 16,000 hours of auxiliary use. Follow the
ally or more frequent based on number of hours run
manufacturer’s recommendations and instructions.
per manufacturer’s recommendations or acceptable
Comply with the manufacturer’s specifications.
industrial engine maintenance procedures. Inspect
c. Short-term (gas turbines). Short-term checklist lubricating oil pumps; flush crankcase and refill.
for gas turbines. Checks are limited to inspection
Refer to manufacturer’s instructions and to the
and cleaning tasks that can be performed on the
Army Oil Analysis Program (TB 43-0210) for in-
exterior of an engine.
structions.
(1) General Comments. Before performing any
(u) Lubricating oil pump. Inspect the pump
tasks required by the following checklist, review the
after 2000 hours of use for proper operation. Refer
station log sheets, related records and the manufac-
to manufacturer’s specifications for the pump.
turer’s recommendations.
(v) Cylinder heads. Remove cylinder heads
(2) The following precautions must be met.
according to the manufacturer’s instructions after
2000 hours of use. Inspect cylinder liners. Clean
Shut the engine down. Apply “Do not operate” tags
and inspect water jackets. Remove scale&and corro-
to the operating controls. Open the engine auto-
sion as necessary. Inspect and measure diameter of
matic start circuit. Deactivate the fire extinguishing
cylinder liners. Check gaskets for annealing, brittle-
system. Keep all engine enclosure doors open while
ness or cracks. Install new gaskets if necessary.
working on the engine. Allow engine to cool down
(w) Piston assembly inspection. On four-
before working on it.
cycle engines, pull one piston after 2000 hours of
(3) Checklist.
use and inspect for proper cooling, lubrication and
(a) Inlet inspection. Verify that the inlet
carbon deposits. Inspect piston rings and wrist pin
drain at lower part of duct is open and free of any
and the cylinder liner for compliance with engine
obstruction so that moisture (rain or condensation)
manufacturer’s specifications.
can run off. Check inlet temperature sensor for
(x) Inspection of pistons. Pull pistons after
signs of damage. Clean sensor and surrounding
4000 hours of engine use. Clean and inspect all
area with approved solvent to remove dirt and con-
parts for wear, proper lubrication and cooling.
taminants. Refer to manufacturer’s instructions.
Verify that rings and ring clearances comply with
Make sure sensor is securely attached to engine.
engine manufacturer’s specifications.
(b) Exhaust inspection. Visually inspect en-
(y) Cylinder inspection. Use the barring de-
gine exhaust casing, struts, and center body for
vice (jacking bar) to turn each piston to top dead
cracks, nicks and other signs of damage. Refer to
center during step x. Inspect each cylinder liner for
manufacturer’s instructions. Inspect exhaust stack
scoring. Refer to manufacturer’s instructions.
for freedom from obstructions and general good con-
(z) Anchor bolts. Check anchor bolts for
dition.
proper torque value.
(c) Chip detectors. Engines usually have
(aa) Flywheel bolts. Check flywheel bolts for
plugs with magnetic chip detectors at lubrication
proper torque value. Refer to manufacturer’s in-
sumps. During normal operation, some fuzz-like
structions. Verify alignment and coupling to genera-
particles will be found on the detectors. Also, other
tor, comply with specifications.
materials (non-metallic sludge and/or flakes, bronze
(ab) Main and crankpin bearings. Remove
powder, aluminum chips, etc.) may accumulate on
bearing caps; check journals and bearings for
the plugs. Refer to manufacturer’s literature for
proper lubrication, wear or scoring. Check main
specific information. Check chip detectors for elec-
bearings for proper alignment. Refer to manufactur-
trical continuity while installed. Continuity is an
er’s instructions.
indication of contamination. Remove chip detectors
(ac) Crankshaft. Verify compliance with en-
if contaminated. Discard packing and clean chip
gine manufacturer’s specifications. Examine crank-
detector. Check chip detector for good thread and
shaft for cracks. Measure distance between
proper magnetism. Place new packings on chip de-
7-3
TM 5-685/NAVFAC MO-912
tectors and install on engine. Tighten to proper
air at about 25 psi monthly. Check brushes for wear
torque.
and indications of arcing and chattering monthly.
(d) External inspection. Inspect engine
Check condition of slip rings. Refer to manufactur-
tubes, hoses, tube/hose fittings, electrical assem-
er’s instructions.
blies and connectors for security, and overheating
(g) Static exciters. Verify that the equipment
and damage due to leakage. Perform inlet and ex-
is clean and free from dirt and moisture. Verify that
haust inspection as described previously. Check
all connections are tight. Check connections for cor-
standoffs, brackets and struts for looseness, cracks,
rosion and clean as required.
and damage. Check ignition exciter, igniter plugs
b. Long-term. Long-term checklists for genera-
and leads for damage, overheating and security.
tors and exciters.
Check mechanical control for signs of excessive
(1) General comments. The following tasks
wear, damage and security. Check fuel manifold for
should be performed annually unless otherwise
leaks, signs of damage and security. Check for rust
noted, following performance of short-term checks.
and/or corrosion.
(2) Checklist and schedule.
d. Long-term (gas turbines). Long-term checks
(a) Coupling Lubrication. Drain lubricant,
usually affect interior areas of the engine and are
disassemble and clean the coupling annually or
seldom performed in the field. Repairs, if necessary,
whenever necessary. Reassemble, using new gas-
may involve changes in component balance relation-
kets and fresh lubricant. Refer to manufacturer’s
ships and should be performed at the designated
instructions for flexible coupling.
overhaul location. Refer to the manufacturer’s lit-
(b) Brush replacement. When brushes have
erature for information.
worn to half their original length, replace, seat
properly and adjust brush rigging tension from 2.5
7-3. Generators and exciters.
to 3.6 psi on brush riding surface. Repair and re-
Routine maintenance instructions for generators
place damaged or worn brush rigging parts. Refer to
and exciters consist of short- and long-term check-
manufacturer’s instructions.
lists for rotating and static type equipment.
(c) Brush electrolysis. Electrolytic action can
a. Short- term. Short-term checklists for genera-
occur at collector ring surfaces. This action forms a
tors and exciters.
greenish coating (verdigris) on brass, bronze or cop-
---
(1) General comments. Before performing any
per. Effects of this action can be reduced or elimi-
tasks required by the following checklist, review the
nated by reversing the polarity annually or as re-
station log sheets, related records and the manufac-
quired. Refer to manufacturer’s instructions.
turer’s recommendations.
(d) Commutator and collector rings. Clean
(2) Checklist .
commutator and collector rings with vacuum. Clean
(a) Air screens or filters. Air screens or filters
oil film and dirt with approved solvent. Dry with
should be changed when the air flow is restricted
compressed air at about 25 psi. Check for rough-
enough to increase generator operating tempera-
ness, hard spots and out-of-round condition. Service
ture. Refer to manufacturer’s literature.
commutator and collector rings as necessary follow-
(b) Exciter coupling (if applicable). When the
ing manufacturer’s instructions.
generator unit is shut down prior to operation, wipe
(e) Rotor winding. Rotor maintenance begins
off excess lubrication from the coupling to prevent
with measuring and recording the insulation resis-
spatter.
tance before the unit is placed in service. Refer to
(c) Coupling Leaks and alignment. When the
manufacturer’s literature for instructions. The rotor
generator has been shut down, check for lubrication
should be thoroughly cleaned annually and in-
leaks and tightness of coupling. Note ahy evidence
spected as follows: Check the damper winding for
of improper alignment and correct if necessary.
loose bars and the connection of each bar to its ring
(d) Axial position. Check axial position of the
segment