Low Load Operation - TEKSAN DIESEL GENERATOR SETS Operation And Maintenance Manual

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• The radiator must be cleaned properly and periodically for the reason above. Low pressure steam should be
used for this cleaning purpose. The radiator can be immersed into an alkaline solution in case of any stronger
sediments. The radiator must be washed with hot water after waiting at least 20 minutes inside this solution.

5.9.Low Load Operation

Besides overloading, running a generator set under too light loading conditions can also be harmful for the
generator set. Running the generator set below a specified loading rate may cause damage on engine and reduce
its reliability. This fact must be taken into consideration, especially in higher capacity generator set applications.
Any generator set to be used in a standby application must be loaded not less than 30% of its full capacity.
Any generator set must not be running under no-load or low-load conditions for a long time. If you really have to run
it in such conditions, then the duration shall be minimized. For example; if the weekly test will be performed without
load, then it should not take more than 10 minutes.
Any engine which has operated under a 30% or less loading condition for 1 hour, must be operated with a 60% load
for 30 minutes in order for the engine to re-gain its performance.
For burning and cleaning any remaining carbon compounds inside the engine and exhaust system, any generator set
must be operated with a 75% load and for a 4 hours duration every year. The load level must be increased gradually.
If the sufficient loading rate cannot be provided for the generator set, then a dummy load can be connected to it.
Maintenance intervals must be more frequent for the generator sets running under low loading conditions. For
example the air filter must be replaced every year, the oil filters must be changed every 6 months if a generator set
is running in standby mode and under low loading conditions.
Here are some problems that may occur in case of running the generator set under low loading conditions;
Oil Leakage at Exhaust or Air Inlet Systems
• Since the temperature inside cylinders will be less than normal level, the fuel delivered to cylinders cannot be
combusted properly. Unburned fuel and oil steam become condensed in the exhaust system.
• Also the turbocharger oil seals cannot function properly due to this lower temperature, so the oil will be leaking
with air to the air inlet and exhaust systems.
• Due to these two reasons above, oil leakage problems can be seen on air inlet and exhaust manifolds and so
the oil consumption of the engine will be higher than normal.
This situation is faced especially on Standby(ESP) generator sets which are operated with no load during weekly
test running.
Carbon Accumulation on Cylinder Covers and Exhausts Manifolds
In case of operating the diesel engine under low load for a long time, the combustion process is performed under
low temperature. As a result of this low quality combustion, there may be oil steam and soot contaminated at
cylinder covers, valves, piston rings, exhaust manifold and injector nozzles. This all will lead up to a lower engine
performance and possibly a serious damage on the engine later.
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