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5 Common Causes of Generator Failure to Look Out For

5 Common Causes of Generator Failure to Look Out For

Generators are essential machines in almost every industry. Industrial generators are mainly used to supply backup power to facilities, businesses, and even homes during power outages. In areas where a local electrical grid is unavailable or hard to access, generators are also used as the main power source.

Indeed, generators serve various purposes. For this reason, it is important for generators to be regularly protected, checked, and maintained. Proper maintenance is the key to a long-lasting generator.

To properly maintain generators, it is necessary to know the common failures that can damage them to know when there is a need for a generator overhaul.

Here are some of the most frequent causes of generator failure that should always be on the lookout for.

1. Overheating

Overheating is one of the most common diagnoses for electric motor repairs. In generators, overheating can result from several things, including generator overload, overspeed, winding insulation breakdown, and inadequate bearing oil lubrication.

When the generator begins to overheat, the alternator will overheat as well, and it will drastically reduce the insulating properties of the windings. If left neglected, overheating will then cause further damage to the other parts of the generator, which may necessitate repair or replacement.

2. Fault Current

A fault current is any unintentionally high current flow in an electrical system. These faults can cause many kinds of problems to your generator. They are usually caused by short circuits with low impedance.

If the fault is a short circuit across the generator windings, it is crucial to have your generator immediately checked or repaired since there is a chance for the winding to heat up and become damaged.

3. Motoring

Generator motoring occurs when the prime mover cannot supply adequate power to the generator to account for its load demand. Here, the generator system is forced to compensate for the losses by supplying real power to the prime mover, essentially making the generator act like a motor.

Motoring does not immediately harm the generator. However, if neglected, it can cause the prime mover to overheat. So, it is necessary to have protection against generator motoring, which can be provided by limit switches or exhaust hood temperature detectors.

4. Loss of Residual Magnetism

Residual magnetism refers to the amount of magnetisation left behind after the removal of the external magnetic field from a circuit. It is typically seen in generators and motors. Losing this residual magnetism in a generator can cause some issues to the system.

Loss of residual magnetism happens when a generator is not used for a long time because of ageing or erring connection of field winding. When this residual magnetism is lost, the generator will not produce any power at start-up.

5. Under Voltage

If the voltage cannot rise after the generator has started, then the machine might be facing some serious issues. Generator under voltage can occur randomly for various reasons, including blown voltage-sensing fuses and broken excitation circuits.

Another possible reason behind under voltage in a generator is lack of use. Its alternator uses residual magnetism for the windings to charge the capacitor. If the generator has not been used for an extended period of time, the capacitor will not be charged. An insufficient capacity will then cause a low voltage reading from the generator.

Generator protection and maintenance is necessary. If not fixed immediately, issues such as overheating, fault current, motoring, loss of residual magnetism, and under voltage can cause irreversible damage to the generator.


Generators are the vital backbone of any endeavour that does not have access to the normal power grid, whether it be getting life-preserving hospital machines to continue working during a power outage, or as the primary source of power during outdoor work such as construction and agriculture.

Thus, a generator breaking can have dire consequences. Hence, you should be aware of the most frequent causes of generator failure so that you can catch and fix them before they significantly damage your generator.