Maintenance Methods for Diesel Generators

I. Pre-start Inspection (Before Every Use)

1. Engine Oil Inspection

1. After shutting down and standing for 5–10 minutes, pull out the oil dipstick. Maintain the oil level midway between the upper and lower scale marks.
2. Replace the oil immediately if it turns black, becomes thin, or contains impurities.
3. Change engine oil every 250–300 operating hours. Use -10# or -20# antifreeze engine oil in winter.

2. Coolant (Antifreeze) Inspection

1. Keep the water tank liquid level at the marked line. Top up with antifreeze of the same model when low; never add tap water directly.
2. Prevent overheating and boiling in summer; drain all cooling water after shutdown in winter to avoid cylinder block cracking from freezing.

3. Fuel System

1. Use qualified national standard diesel. Regularly drain accumulated water and sediment from the bottom of the fuel tank and diesel filter.
2. Check fuel pipes for damage and oil leakage; fasten all pipe joints and bleed air fully to avoid unexpected shutdown due to fuel supply interruption.

4. Battery Inspection

1. Voltage standard: 24V units shall maintain 24–27V; 12V units shall stay above 12.5V.
2. Check terminal posts for looseness, oxidation or white powder; fasten terminals regularly and clean terminal connectors.
3. For long-term idle storage, charge the battery every 15 days to avoid damage from power depletion.

5. Appearance & Earthing Inspection

1. The main earthing cable of the complete unit must be firmly connected to prevent electric leakage.
2. Clear dust, catkins and debris from fans and heat sinks; inspect exhaust ducts of silent-type units for unobstructed ventilation.

II. In-operation Maintenance (While Running)

1. Monitor dashboard readings: engine oil pressure, coolant temperature, voltage and frequency. Normal coolant temperature ranges from 75℃ to 90℃; standard engine oil pressure is 0.25–0.4 MPa.
2. Strictly prohibit long-term overloaded operation. The optimal load range is 70%–80% of rated power to extend unit service life.
3. Do not start or stop the unit with sudden full load; increase and decrease load gradually.
4. Listen and observe for abnormal noises or exhaust smoke during operation:

• Black smoke: Excessive load or clogged air filter
• Blue smoke: Engine oil burning inside cylinders
• White smoke: Water contained in diesel fuel or cylinder block faults

5. Ensure good ventilation in the generator room. For fully enclosed rooms, guarantee smooth air intake and exhaust.

III. Periodic Scheduled Maintenance (By Operating Hours)

1. 50-Hour Maintenance (Short-term Routine Service)

1. Clean the air filter. In dusty environments, blow compressed air from inside out. Replace the air filter directly if severely clogged.
2. Inspect battery wiring and belt tension (generator drive belt).
3. Drain accumulated water and impurities from diesel filters and water-oil separators.

2. 250–300-Hour Maintenance (Primary Maintenance)

1. Replace engine oil and oil filter.
2. Replace diesel filter and water-oil separator element.
3. Thoroughly clean the air filter; install a brand-new filter under harsh working conditions.
4. Tighten all bolts on the complete unit; inspect oil pipes and water pipes for leakage.

3. 500-Hour Maintenance (Secondary Maintenance)

1. Complete all service items of Primary Maintenance.
2. Replace antifreeze; clear dust from the exterior of the water tank and clean the radiator.
3. Inspect carbon brushes and slip rings of the alternator, remove dust deposits, and replace carbon brushes with excessive wear.
4. Calibrate the Automatic Voltage Regulator (AVR) and check all wire connectors.

4. 1000-Hour Major Overhaul (Comprehensive Deep Maintenance)

1. Replace all filter elements, engine oil and antifreeze.
2. Test and calibrate fuel injectors and high-pressure fuel pumps.
3. Inspect and adjust valve clearance.
4. Remove dust from stator and rotor, and test winding insulation performance.
5. Check clutches and shock-absorbing pads for aging or cracking.

IV. Maintenance for Long-term Idle Storage (Export Standby Units & Stock Units)

1. Run the unit under no load for 15–20 minutes to fully drain residual water from pipelines.
2. Drain all engine oil, diesel fuel and cooling water.
3. Remove the battery for separate storage and charge it once every month.
4. Seal air intake and exhaust openings, cover the entire unit with a rainproof and dustproof cover, and store it in a dry and well-ventilated room.
5. Start the unit once every 30 days and run it for 10–15 minutes.

V. Key Maintenance Points for the Alternator (Electrical Section, Excluding Diesel Engine)

1. Prevent the unit from being soaked by rain; install rainproof covers for outdoor mobile power stations.
2. Keep the interior of the alternator stator dry and free of water ingress or dampness; dry the windings thoroughly before operation if used in humid environments.
3. Avoid long-term overload or short-circuit operation; short circuits can easily burn out the stator windings.
4. Measure insulation resistance of windings once every year.

VI. Operation Prohibitions (For Overseas Customers)

1. Never operate a cold unit under full load immediately; preheat the engine for 3–5 minutes first.
2. Do not shut down the unit right after high-temperature operation; run it under no load for several minutes to cool down before shutdown.
3. Only use lubricating oil, antifreeze and diesel fuel of specifications specified by the original manufacturer.