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Small current powered by diesel generator set 

Want to know the reasons for a small current powered by a diesel generator set? Then you’ve come to the right place. Read this blog post to know all the reasons.

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If you want to know why a diesel gensets powers a small current, you’ve come to the right place. This blog post will discuss the common reasons behind this issue.

Let’s get started.

There are several reasons why a diesel generator set may produce low current output, including:

a) Load demand

The current output will also be small if the connected load exceeds the generator’s capacity. Diesel generators are designed to produce a specific amount of power, and if a much smaller load is connected, the current output will also be reduced.

b) Generator size

The size of the generator also affects the current output. The current production will be low if the generator is more significant for the connected load.

c) Component failure

Component failure in the generator can also cause low current output. For example, a faulty voltage regulator can prevent the generator from producing the voltage needed to drive the load.

d) Poor fuel quality

Poor fuel quality can also cause low current output. If the fuel is contaminated or has low energy content, the generator may not be able to produce the required power output.

e) Engine wear

Diesel engine wear can also affect the generator’s ability to generate electricity. If the engine is damaged or worn, it may not be able to produce the torque needed to drive the generator at full capacity.

Some other reasons can be:

  • The cable is loose: the lead wire of the silicon diode of the diesel generator is broken, and one or two phases of the armature coil are broken
  • The regulator voltage is low
  • The belt slips
  • Partial short circuit
  • Poor contact leads to increased resistance

Factors affecting generator output rating

All appliances are set for optimum operating conditions. Any fluctuations in these conditions can prevent the equipment from operating less efficiently. Generators are no exception. Generators are typically designed to work most efficiently at or near sea level under standard temperature and pressure (STP) conditions.

Any fluctuations in STP conditions can damage the generator and cause output to drop. In extreme cases, the generator may stop running altogether. Many of these factors are relatively minor for most applications unless the generator set is operated at altitudes greater than 5,000 feet or the ambient temperature remains above 100 degrees Fahrenheit for extended periods. Particular attention should be paid to compensating for these corner cases, as discussed below.

Ambient temperature conditions are essential for the proper ignition and operation of the generator. Regardless of the fuel that powers, all generators need enough air to burn. Reduced air levels can cause a failed start. In a diesel engine, air and fuel are injected together. The compressed air gets hot, and when peak temperature and pressure are reached, diesel fuel is injected and ignited under given conditions. In gasoline-powered generators, a carburetor introduces an air and fuel mixture immediately and creates a spark to ignite the engine. In both cases, however, sufficient air volume is required for proper start and operation.

a) Altitude

At high altitudes, the decrease in air pressure reduces the density of the air. If not taken into account, this can cause problems with the generator starting, as air is vital to the ignition of any generator.

Another factor that is affected is the availability of ambient air to facilitate the generator’s cooling. The combustion process creates heat, which needs to be dissipated into the environment to keep the engine temperature down. Because of the low air density, heat dissipation is much slower at high altitudes than at sea level, causing engine temperatures to continue to rise. The engine is still hot, and overheating is a common problem in this condition.

b) Temperature

High temperatures may also be associated with lower air density and can create similar ignition problems due to insufficient air supply. This burdens the engine that propels itself to deliver the power it was designed for. However, it failed to do so due to inadequate oxygen levels available for combustion. In many of these cases, the engine overheats and sometimes crashes completely.

c) Humidity

Humidity measures the water content in a given volume of air. In highly humid conditions, water vapor in the air displaces oxygen. Low oxygen levels can affect ignition because oxygen is an element in the air that is ignited in the engine to burn fuel.

diesel generators displayed on the lawn

d) Rating generators

BISON Generators come in a variety of sizes. Each of them is preset for a specific output level. Generators are selected and installed according to the electrical requirements of any facility. A standard generator is ideally set to run at 80% of its capacity for continuous use. In an emergency, it can be used with 100% efficiency. Various companies that manufacture generators have now developed standard ratings for these generators, giving buyers an idea of actual generator capacity. Depending on the consumer’s requirements, he can choose between the available brands since the capacity of each brand is standardized according to international standards.

e) Derating generators

We have seen above how non-standard environmental conditions can reduce generator power output. In this case, how to guess the new output level? A “derating” technique determines how the generator will perform under new environmental conditions. Derating is a method employed in power electrical and electronic equipment in which the equipment operates below its rated maximum power consumption.

Generator derating depends on the manufacturer of the equipment. Different manufacturers design generators using materials from various sources. Also, design development is dissimilar, and in many cases, technology is too. All of these contribute to improving the overall efficiency of the generator. Therefore, the derating of the generator depends on the manufacturing process. Different brands have different derating factors for calculating generator output under non-standard environmental conditions.

However, general formulas can be used to calculate approximate estimates of output levels. Standard derating formulas state that gasoline, diesel, or liquid propane generators should typically be derated by 2-3% of their standard output for every 1000 feet of altitude increase. The derating factor for generators running on natural gas is usually closer to 5%.

f) Fuel problems

At low temperatures, insufficient oxygen levels can cause starting problems; another common problem is diesel fuel gelling. Low temperatures can cause diesel fuel to gel, which alters the fuel’s flow characteristics. This gelation is attributed to the paraffin content in the diesel. Certain diesel types, such as low-sulfur diesel, have higher paraffin content than others.

At low temperatures, paraffin can crystallize and clog fuel filters. When the fuel filter becomes clogged, the extra fuel cannot quickly enter the combustion chamber, and the air-fuel ratio changes, resulting in incomplete combustion. In this case, the alternator engine may not start.

Two methods are generally used to avoid gelling: a) Winterizing the fuel and b) adding anti-gelling additives.

diesel generator placed on the street


The process of blending a commercial grade fuel with a more refined fuel in predetermined proportions to reduce the total paraffin content of the fuel. This is usually done at the distribution establishment before the fuel is delivered to the gas station. Different geographical regions have different mixing ratios according to temperature conditions. In areas with very low temperatures or where the paraffin content of the diesel is high, a higher amount of refined diesel is present in the blend.

Anti gelling agents

These agents prevent diesel fuel from gelling. They alter the fuel’s chemical properties to prevent paraffin from crystallizing and diesel from gelling. It is recommended that the anti-gelling agent be added to the tank before filling it up. These additives must also be adequately mixed in the stated proportions. If your fuel filter is already clogged, various anti-gelling additives are available to unclog the filter and prevent further clogging.

g) Load considerations

As stated in the previous sections, it is understood that STP conditions increase the generator power output due to the maximum air availability and required fuel flow quality. Although designed to take 100% load under standard conditions, it is generally recommended that generators be run at around 80% of their total capacity for maximum and continuous use. In an emergency, however, the generator can be pushed to provide 100% output to critical circuits. According to a maintenance point of view, this does not overload the generator, and the lifetime of the generator set is not negatively affected.


In summary, the causes of small currents powered by diesel generator sets can vary widely but typically include load demand, generator size, component failure, poor fuel quality, and engine wear. Proper maintenance and troubleshooting can help identify and resolve these issues to keep your generator running at optimal capacity.

Diesel Genset  FAQ

Unit sizes from 8 to 30 kW (also 8 to 30 kVA single phase) for homes, small shops and offices, larger industrial generators from 8 kW (11 kVA) to 2,000 kW (3 phase 2,500 kVA) used in office buildings, factories and other industrial facilities.

Diesel generators use a series of steps to produce alternating current (AC). The process begins when a diesel (internal combustion) engine converts some of the chemical energy in the fuel into rotational mechanical energy.

Generators are typically designed to operate most efficiently at or near sea level under standard temperature and pressure (STP) conditions. Any fluctuations in STP conditions can damage the generator and cause output to drop. In extreme cases, the generator may stop running altogether.

If the voltage is too low, the amperage will increase, which can cause components to melt or cause the device to malfunction. If the voltage is too high, it will cause the appliance to run “too fast and too high”, shortening its lifespan.

To increase the generator’s power, you can replace the magnets with stronger magnets or replace the coils. The new coil must have more windings than the previous coil. The more windings the coil has, the more power the generator can output.

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