Onan DYG Series Operator's Manual And Parts Catalog page 32

E X E R C I S E P E R I O D
Generating sets on continuous standby service are
required to be operative at full load from a cold start in
less than 10-seconds in the event of a power outage.
This imposes severe conditions on the engine. Fric-
tion of dry piston rings upon dry cylinder walls causes
scuffing and rapid wearing. These can be relieved by
exercising the set at least once a week for a minimum
time of 30-minutes per exercise period. Preferably,
run the set under at least 50 percent load to allow the
engine to reach normal operating temperature. This
will keep engine parts lubricated, maintain fuel prime,
prevent electrical relay contacts from oxidizing and
insure easy emergency starts. ONAN automatic
transfer switches contain an optional exercise switch
which, by pre-selection, will start, determine run
period and shut down a set on a weekly frequency.
For example, the switch can be set for time of start,
length of run, A.M. or P.M. and day of week.
After each exercise period, refill fuel tank, check
engine for leaks and unit for general condition.
Locate cause of leaks (if any) and correct.
NO LOAD OPERATION
Periods of no load operation should be held to a
minimum. If it is necessary to keep the engine running
for long periods of time when no electric output is
required, best engine performance will be obtained
by connecting a " d u m m y " electrical load. Such a load
could consist of heater elements, etc.
O U T - O F - S E R V I C E P R O T E C T I O N
Generator sets removed from service for extended
periods of time should be protected from rust and
corrosion. The natural lubrication qualities of ASTM
No. 2 Diesel fuel should protect a diesel engine for at
least 30-days when unit is not in service. To protect a
unit that will be out of service over 30 days, Onan
recommends the following procedure:
1. Liquid cooled units. Check coolant, top up if
necessary using recommended anti-freeze.
2. Run set until thoroughly warm; generator under
at least 50% load.
3. Shut down engine and drain oil base while still
warm. Refill and attach a warning tag indicating
viscosity of oil used.
4. Service air cleaner.
5. Clean throttle and governor linkage and protect
by wrapping with a clean cloth.
6. Plug exhaust outlets to prevent entrance of
moisture, bugs, dirt, etc.
7. Clean off dirt and dry entire unit. Coat parts likely
to rust with a light coat of grease or oil.
8. Disconnect battery and follow standard battery
storage procedure. Apply a film of non-
conductive grease (e.g., vaseline) to battery cable
lugs.
9. Fill fuel tank to prevent condensation contamina-
tion.
10. Provide a suitable cover for the entire unit.
RETURNING A UNIT TO S E R V I C E
1. Remove cover and all protective wrapping.
Remove plug from exhaust outlet.
2. Check warning tag on oil base and verify that oil
viscosity is still correct for existing ambient
temperature.
3. Clean and check battery. Measure specific gravity
(1.260 at 77° F (25° C ) ) and verify level to be at
split ring. If specific gravity is low, charge until
correct value is obtained. If level is low, add
distilled water and charge until specific gravity is
correct. DO NOT OVERCHARGE.
WARNING
~\ Do not smoke while servicing batteries.
J Explosive gases are emitted from
batteries in operation. Ignition of these gases can cause
severe personal injury.
4. Check coolant level, adjust if necessary.
5. Connect batteries.
6. Verify that no loads are connected to generator.
7. Start engine.
8. After start, apply load to at least 50% of rated
capacity.
9. Check all gauges to be reading correctly. Unit is
ready for service.
HIGH ALTITUDE
Ratings apply to altitudes up to 1000-feet (305 m),
standard cooling, normal ambients and with No. 2
Diesel fuel. Consult factory or nearest authorized
Onan distributor for operating characteristics under
other conditions.
Engine horsepower loss is approximately 3 percent for each 1000
feet (305 m) of altitude above sea level. Use lower power require-
ment at high altitudes to prevent smoke, over-fueling and high
temperatures.
HIGH T E M P E R A T U R E S
1. See that nothing obstructs air flow to-and-from
the set.
2. Keep cooling system clean.
3. Use correct SAE No. oil for temperature.con-
ditions.
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