**1. Diesel Generator Set Air Filter Contamination**  

Unclean air filters increase resistance, reduce airflow, lower charging efficiency, and result in insufficient engine power.

Clean the air filter element as required, remove dust from paper filter elements, and replace the filter if necessary.

**2. Diesel Generator Set Exhaust Pipe Blockage**  

Exhaust pipe blockage restricts exhaust flow, reduces fuel efficiency, and diminishes power.

Check if excessive carbon buildup inside the exhaust pipe increases exhaust resistance. Generally,

exhaust backpressure should not exceed 3.3 kPa. Regularly clean carbon deposits from the exhaust pipe.

**3. Incorrect Fuel Injection Timing in Diesel Generator Sets**  

Injection timing that is too advanced or too retarded (advanced timing leads to incomplete fuel combustion,

while retarded timing causes white smoke and also incomplete combustion) prevents optimal combustion.

Check if the fuel injection drive shaft coupling screws are loose. If so, readjust the injection timing as specified and tighten the screws.

**4. Scoring or Wear of Piston and Cylinder Liner in Diesel Generator Sets**  

Severe scoring or wear between the piston and cylinder liner, or piston ring coking, increases friction losses,

raises the engine's mechanical losses, reduces compression ratio, causes ignition difficulties or incomplete combustion,

increases blow-by, and leads to significant air leakage. Replace the cylinder liner, piston, and piston rings.

**5. Faults in the Diesel Generator Set Fuel System**  

(1) Air ingress or blockages in the fuel filter or fuel lines restrict fuel flow, reduce power, and may even cause ignition difficulties.

     Bleed air from the fuel lines, clean the diesel filter element, and replace it if necessary.  

(2) Damaged injection components cause fuel leakage, sticking, or poor atomization, often leading to cylinder misfiring

     and reduced engine power. Clean, recondition, or replace the components promptly.  

(3) Insufficient fuel supply from the injection pump also reduces power. Inspect, repair, or replace the components as needed,

     and readjust the injection pump's fuel supply.

**6. Faults in the Diesel Generator Set Cooling and Lubrication Systems**  

Overheating in diesel engines is often caused by faults in the cooling or lubrication systems, leading to elevated water

and oil temperatures and increasing the risk of cylinder scoring or piston ring sticking. When exhaust temperature rises,

inspect the cooler and radiator, and remove scale deposits.

**7. Faults in the Diesel Generator Set Cylinder Head Assembly**  

(1) Exhaust leakage reduces intake air volume or allows exhaust gas to mix with intake air,

     leading to incomplete fuel combustion and power loss. Recondition the contact surfaces of

     valves and valve seats to improve sealing, or replace them if necessary.  

(2) Leakage at the joint between the cylinder head and engine block allows air from the cylinder into the water or oil passages,

    causing coolant to enter the engine. If not detected promptly, this can lead to bearing seizure or black smoke emissions,

    reducing engine power. If the cylinder head gasket is damaged, airflow may escape during speed changes, and bubbles may

    appear at the gasket during operation. Tighten the cylinder head nuts to the specified torque or replace the cylinder head gasket.  

(3) Incorrect valve clearance causes air leakage, reducing engine power and potentially causing ignition difficulties. Readjust the valve clearance.  

(4) Damaged valve springs impede valve return, cause air leakage, and reduce combustion compression ratio,

     leading to insufficient engine power. Replace damaged valve springs promptly.  

(5) Air leakage at the injector installation hole or damaged copper gaskets can cause cylinder misfiring and reduce engine power.

     Dismantle for inspection and replace any damaged parts. If the coolant inlet temperature is too low, heat dissipation losses increase.

     Adjust the inlet temperature to meet the specified value.

**8. Seizing of Diesel Engine Connecting Rod Bearings and Crankshaft Journal Surfaces**  

This condition is accompanied by abnormal noises and a drop in oil pressure, often due to blocked oil passages,

a faulty oil pump, a clogged oil filter, or insufficient or absent oil pressure. Remove the diesel engine side cover,

inspect the side clearance of the connecting rod big end, and check if it can move back and forth. If movement is restricted,

seizing has occurred, and the connecting rod bearings should be repaired or replaced.

**9. Additional Causes for Turbocharged Diesel Engines**  

For turbocharged diesel engines, aside from the aforementioned causes, power loss can also result from worn turbocharger bearings,

blocked or leaking intake passages for the compressor and turbine due to dirt. In such cases, repair or replace the bearings,

clean the intake passages and housing, wipe the impellers clean, and tighten joint nuts and clamps.

**For a diesel generator with a known rated power of 500 kW, what are its output power and maximum current? 

   How are they calculated?**  

Output power is obtained by multiplying the rated power by the power factor. Power is calculated as √3 × current × voltage.

The maximum current can be roughly estimated as 500 × 1.5.

On construction sites using generator power, the output power is often calculated as Rated Power × 80%, which is an empirical value.

The prime power (continuous or long-term power) is commonly used in China to label diesel generator sets, while internationally,

standby power (maximum power) is often used. Irresponsible manufacturers sometimes misleadingly label maximum power as continuous power,

causing confusion. In China, diesel generator sets are labeled with prime power, which refers to the maximum power the set can continuously

deliver within 24 hours. According to standards, the set can be overloaded by 10% above the continuous power for 1 hour within a 12-hour period.

This overloaded power is referred to as maximum power or standby power. For example, if you purchase a 400 kW prime power set, it can operate

at 440 kW for 1 hour within 12 hours. However, if you purchase a 400 kW standby power set and operate it continuously at 400 kW without overloading,

the set is actually operating in an overloaded state (since its actual rated power is only 360 kW), which can shorten its lifespan and increase failure rates.

Diesel generator power is not labeled in terms of capacity. Diesel generators range from 10 kW to 1500 kW.

To calculate the rated current, take a 500 kW generator as an example:  

500 kW = 500,000 W. Divide this power by the voltage (nominally 380 V, but generators typically output slightly below 400 V):  

500,000 / 400 = 1250 A (amperes).  

This is the current. However, diesel engines cannot operate at full load continuously, similar to how a car labeled for 220 km/h

is not driven at that speed constantly. Similarly, for diesel generators, a reliable generator typically operates at 80% of this value:  

1250 × 0.8 = 1000 A, which is the rated current.  

Even operating a 500 kW generator continuously at 1000 A is risky. Domestic generators are even less suitable for such conditions,

as the diesel engine cannot withstand it. Diesel generators can also be categorized into mobile and silent types, which may further reduce current output.

**Guangzhou Generators | Yuchai Generators | Foshan Generators — Guangdong Longhong Electromechanical Equipment Co., Ltd.**  

**www.longhongpower.com**