Analysis and Handling of Common Faults of Small Generators
Small gasoline or diesel generators are widely used as backup or mobile power sources in homes, shops or outdoor operations. However, during the usage process, it is inevitable to encounter faults such as failure to start and unstable output. A systematic analysis of it can quickly locate the problem, saving maintenance time and costs.
1. The generator fails to start or has difficulty starting
This is the most common malfunction, usually caused by problems with the fuel, ignition and intake systems.
1. Fuel system issues
· Insufficient or deteriorated fuel: Check the fuel level in the tank and ensure that the fuel valve is open. More importantly, gasoline stored for more than three months may deteriorate and form gum that clogs the carburetor. The old oil should be drained, the carburetor cleaned and fresh fuel added.
· Carburetor blockage: Impurities or gum in the fuel can clog the orifice and fuel passage of the carburetor, preventing the fuel from being injected normally. The carburetor needs to be disassembled and thoroughly cleaned.
· Spark plug failure: Remove the spark plug and check whether the electrode gap is normal (usually 0.7-0.8mm), and whether there is carbon deposit, oil stains or erosion. Clean or replace when necessary.
2. Ignition and intake system issues:
· Air filter clogging: A too dirty air filter can seriously affect the intake efficiency, causing the mixture to be too rich and preventing the engine from starting. The air filter should be cleaned or replaced regularly.
Improper start-up operation: For models with manual dampers, if the damper (choke) is not closed during cold start-up, it will cause the mixture to be too thin and make it difficult to start.
2. Insufficient output power of the generator or unstable voltage
If the generator can start but cannot drive the load, or if the lights flicker, it is considered an abnormal output.
1. Excessive load: Check whether the total rated power of the connected equipment exceeds the maximum output power of the generator. Overload operation should be avoided.
2. Unstable engine speed: The engine speed is directly related to the output voltage and frequency. Unstable rotational speed is usually caused by the following reasons:
· Improper carburetor adjustment: Poor fuel supply through the idle screw or the main fuel gauge hole.
· Poor fuel supply: The fuel filter is slightly clogged or there is moisture in the fuel line.
· Governor failure: The connecting rod of the mechanical governor is stuck or the spring is loose, causing the throttle to be unable to stabilize at the rated speed.
3. Generator body failure
· Carbon brush wear: For brushed generators, excessive wear of carbon brushes can lead to poor contact with slip rings and unstable output voltage. The carbon brushes need to be inspected and replaced.
· Excitation loss: Generators that have been idle for a long time may lose residual magnetism, resulting in the inability to establish voltage. Magnetization operation is required.
· AVR (Automatic Voltage Regulator) damage: The AVR is the core component for stabilizing the output voltage. If it is damaged, it will cause the voltage to be too high, too low or have no output at all.
Iii. Abnormal operation of the generator and sudden shutdown
1. Overheating shutdown: Check whether the air intake of the cooling fan and the heat sink are blocked by dust or debris, which may cause poor heat dissipation. Make sure the generator operates in a well-ventilated environment.
2. Oil alarm: Most small generators are equipped with a low oil level shutdown protection system. When the engine oil is insufficient, the system will automatically cut off the ignition to protect the engine. The oil level should be checked and replenished in time.
3. Abnormal noise and vibration: Possible causes include loose engine fixing screws, wear and damage of internal moving parts (such as bearings), or fan blades touching the casing, etc. The machine should be stopped immediately for inspection.
Summary
When conducting fault analysis on small generators, the principle of “from simple to complex and from outside to inside” should be followed. First, check the daily maintenance items such as fuel, engine oil, air filter and spark plugs, and then conduct a thorough inspection of the carburetor, governor and electrical components (such as AVR). Regular maintenance is the best way to prevent faults, which can effectively extend the service life of the generator and ensure its reliable operation at critical moments. (Honda)
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