When a diesel generator set operates under overload conditions, the following problems may arise. These impacts often have a cascading effect and require special attention:
- Excessive Wear of Core Components
In an overload state, the combustion temperature inside the engine cylinder may exceed 1000°C, far surpassing the design threshold. The lubricating film between the piston rings and cylinder sleeves may be destroyed, and actual test data shows the wear rate can be 3-5 times higher than under normal conditions. The crankshaft bearings may suffer adhesive wear due to the breakdown of the oil film. In one case, continuous 30 minutes of 110% overload led to a seized crankshaft that required repair. - Multiple Faults in the Power System
When the load exceeds 15% of the generator’s rated capacity, the temperature rise in the windings can reach 130% of the K-class insulation limit. In a hospital backup power case, 25 minutes of overload caused the stator winding insulation to embrittle, leading to an inter-phase short circuit. At the same time, voltage fluctuations reached ±12%, which caused the mainboard of CT equipment to burn out, resulting in repair costs exceeding 200,000 yuan. - Malicious Cycle in the Combustion System
Under overload conditions, the fuel injection volume may increase by 30%, which can lead to poor atomization. Unburned hydrocarbons in the exhaust increase by 2.3 times. A test in a ship’s power station showed that after 2 hours of continuous overload operation, the thickness of the turbocharger carbon deposit reached 1.8mm, reducing intake efficiency by 19%, forming a vicious cycle of increased fuel consumption and decreased power. - Risk of Protection System Failure
When the overload multiple exceeds the instantaneous setting value of the circuit breaker (usually 3-5 times the rated current), if the protection device does not act in time, local hotspots in the windings may reach the copper melting point (1083°C) within 90 seconds. An investigation into an industrial accident showed that contact oxidation in the plastic shell circuit breaker delayed tripping, causing the generator to catch fire. - Significant Increase in Hidden Costs
Statistics show that every 10% increase in the rated load reduces the overhaul cycle by 40%. In one data center calculation, an average of 200 hours of overload operation per year shortened the generator’s lifecycle from 15,000 hours to 9,000 hours, resulting in a 58% increase in operating costs per hour.