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What are the hazards of running a diesel generator set in low load mode?

June 16, 2022
We all know that maintaining the best condition of diesel generator set plays a vital role in the operation of the enterprise. Once the generator set fails, it will easily have a huge negative impact on the production business of the enterprise, and lead to the failure of Yuchai diesel generator set. There are many reasons, one of which is low load mode operation.
What is low load?
Diesel generator set manufacturers typically specify the minimum allowable load for diesel generators (by stating a percentage of their rated capacity) in order to provide the operator with a recommended load. For example, the minimum load is set to 40%. If the power required by a diesel generator is 50% of its capacity, it runs at 50% speed. On the other hand, if it’s 30% – it still starts out at 40%. The excess power will be used to charge the battery, used as a delay load, or simply thrown away. In this case, anything below 40% is considered a low load. Running under low load will reduce the performance of Yuchai generators, which may lead to serious failure of the generator set.
Hazards of low-load operation of diesel generator sets
1. Increase the wear of parts
If the diesel generator set runs at low load for a long time, it will cause more serious wear and tear of moving parts and deterioration of engine combustion environment, which will lead to the consequences of early overhaul period.
2. Blue smoke from exhaust
The piston and cylinder liner are not well sealed, the oil runs up, enters the combustion chamber and burns, and the exhaust emits blue smoke.
3. It is easy to cause oil leakage
When the oil in the supercharging chamber of the supercharger accumulates to a certain extent, it will leak out from the joint surface of the supercharger.
4. The oil is running around
For a supercharged diesel engine, the boost pressure is low due to low load and no load. It is easy to cause the sealing effect of the supercharger oil seal to decrease, and the oil escapes into the supercharger chamber and enters the cylinder with the intake air.
5. Carbon deposits
Part of the oil that goes up to the cylinder participates in the combustion, and part of the oil cannot be completely burned, forming carbon deposits on the valve, intake port, piston crown, piston ring, etc., and part of it is discharged with the exhaust. In this way, oil will gradually accumulate in the exhaust port of the cylinder liner, and carbon deposits will also be formed.
Through the above introduction, we know that if the generator is used under low load conditions for a long time, it will easily cause carbon deposition and aggravate the wear of components, which will affect the service life of the machine. To operate in low load mode, it is recommended to use the diesel generator set under low load conditions for no more than 15 minutes.