+27 11 824 0001



How Generators Work?

How Generators Work? Electrical generators function as autonomous machines, furnishing electrical energy in instances where the local power grid is inaccessible. Industrial generators, on the other hand, serve as crucial backup power sources for facilities, businesses, and residences during power outages. They can also serve as the primary power supply in regions lacking a local electrical grid or where access is challenging, such as in mining, agriculture, new developments, and construction projects

Generators are available to cater to diverse needs. Some are compact and portable, suited for activities like camping or hobbies, offering power for a limited number of devices. In contrast, others are permanent fixtures capable of powering entire households. Industrial generators exhibit even greater potency, sustaining uninterrupted power for manufacturing plants, hospitals, and office complexes.

The generator landscape includes various types, such as diesel generators, natural gas generators, propane generators, and bi-fuel generators. In the following sections, we’ll delve into the mechanics of electrical generators, as well as the essential information for their installation and maintenance.

How Generators Work Engine

How Do Generators Create Electricity?

Generators, in essence, do not generate electricity per se. Rather, they transform either mechanical or chemical energy into electrical energy. This conversion process involves harnessing kinetic or chemical energy and channeling it into electrical energy by compelling electrons from an external source to traverse an electrical circuit. Effectively, a generator functions as an electrical motor operating in reverse.

In certain instances, such as the massive generators at Hydropower, colossal amounts of energy are produced by converting the kinetic energy derived from water-rotating turbines into electricity. In contrast, residential and commercial generators, typically of smaller scale, rely on conventional fuel sources like diesel, gasoline, or propane to generate mechanical power. This mechanical power is then channeled into an electrical circuit to induce an electrical current.

Once an electrical current is established, it travels through copper wires, delivering power to external machinery, devices, or entire electrical systems.

What Are The Parts Of An Electrical Generator?

A generator comprises nine integral components, each playing a crucial role in delivering power precisely where it is required. These generator components encompass:

  • Engine: The engine serves as the energy source for the generator, and its power output dictates the electrical capacity the generator can provide.
  • Alternator: Also referred to as a “genhead,” the alternator is where the transformation from mechanical energy to electrical energy transpires. It encompasses both moving and stationary elements working in tandem to generate an electromagnetic field and facilitate the movement of electrons that generates electricity.
  • Fuel System: The fuel system is responsible for enabling the generator to generate the necessary energy. Comprising a fuel tank, a fuel pump, connecting pipes between the tank and the engine, and a return pipe, this system ensures a constant fuel supply. Additionally, it incorporates a fuel filter to eliminate debris before reaching the engine, with an injector directing fuel into the combustion chamber.
  • Voltage Regulator: This essential component regulates the voltage of the generated electricity and can convert it from AC to DC as required.
  • Cooling and Exhaust Systems: Generators generate substantial heat during operation. The cooling system prevents overheating, while the exhaust system manages and expels the fumes produced during operation.
  • Lubrication System: A generator contains numerous small, moving parts that require adequate lubrication with engine oil to ensure seamless operation and protect against excessive wear. Regular lubricant level checks, as frequently as every 8 hours of operation, are imperative.
  • Battery Charger: Batteries are employed to initiate generator startup. The battery charger is a fully automated component that maintains the battery’s readiness by supplying a constant, low-level voltage.
  • Control Panel: The control panel oversees all facets of generator functionality, from startup and running speed to output management. Modern units possess the capability to sense power fluctuations or outages and can initiate or halt generator operation automatically.
  • Main Assembly / Frame: This component constitutes the generator’s structural body, the visible and supportive framework that houses all other parts securely.

Together, these nine components collaborate to ensure the generator performs optimally and delivers dependable power where it’s needed most.

How A Generator Work Image

What Kind Of Fuel Do Electrical Generators Need?

Present-day electrical generators offer a diverse array of fuelling choices to cater to various needs. Diesel generators reign supreme as the favored choice among industrial generators. Conversely, residential generators predominantly feature natural gas or propane variants. In the realm of smaller, portable generators, gasoline, diesel fuel, and propane configurations are more common. Additionally, certain generators showcase bi-fuel capabilities, enabling them to operate on both gasoline and diesel fuels.

Generator Fuel Tanks.

The fuel system ensures that the generator has the necessary resources to initiate the internal combustion process, a crucial step for converting mechanical energy into electrical energy. Without fuel, combustion cannot occur, rendering the generator incapable of producing electricity. It is essential to have on-site fuel storage to enable immediate operation when needed.

Fuel tanks vary in placement depending on the generator type and application. They may be affixed to the generator frame or situated externally, at a distance from the actual generator. Generally, larger generators with extended run times necessitate larger fuel tanks. These tanks, with diverse capacities, cater to specific generator uses and power requirements. They can be positioned above ground, underground, or at a sub base level. Sub base tanks, designed for storing less than 1,000 gallons of fuel, are placed above ground but below the generator set’s base.

Above ground and below ground fuel storage tanks are suitable for high-capacity needs. Although underground tanks entail higher installation costs, they tend to have a longer lifespan due to protection from the elements. Decisions regarding fuel storage tanks must align with numerous code requirements and approvals, applicable for both residential and commercial installations.

To determine the minimum fuel tank capacity needed, consider your intended generator usage. For short or infrequent power outages, a backup generator with a smaller storage tank may suffice, but more frequent refilling will be required. Larger storage tanks are recommended for powering large commercial facilities with a primary generator or in areas prone to extended, frequent power disruptions. Your generator supplier can assist in determining the optimal tank size to ensure sufficient fuel availability.

It’s imperative to consider the cost and accessibility of fuels in your location when purchasing a generator and selecting a fuel storage tank. Consult local fuel suppliers to gain a better understanding of the logistics and expenses involved.

Generator Exhaust Systems and Emissions Controls.

Generators, as continuous-running machines powered by fossil fuels, require components for cooling and emissions filtration. Cooling and ventilation systems serve to reduce and expel heat: 

  • Water: Used selectively or for very large units, water serves as a coolant to regulate generator temperature.
  • Hydrogen: An efficient coolant, hydrogen absorbs heat emitted by the generator, transferring it to a secondary cooling circuit.
  • Radiators and fans: Smaller generators rely on a combination of radiators and fans for cooling.

Emissions from generators, akin to those of other gas- or diesel-powered engines, contain harmful chemicals like carbon dioxide. These emissions are filtered and expelled by the generator exhaust system. Exhaust pipes extend from the engine, directing fumes safely away from the generator and its surroundings.

Certain generators are subject to federal emission controls, monitoring Nitrogen Oxide (NOx), Hydrocarbons, Carbon Monoxide (CO), and Particulate Matter. While emergency generators and those running less than 100 hours annually usually bypass federal regulations, permanently installed prime generators and standby generators adhere to federal emissions requirements under specific EPA rules. Many modern generators already meet these emissions standards, owing to manufacturing advancements. Older units may be exempt based on grandfathering clauses, making them subject only to state and local emissions standards. Emissions control specifications vary by manufacturer, generator size, and production date, necessitating consultation with your generator dealer or manufacturer for precise requirements.

Generator Engine

The Generator Control Panel And Automatic Transfer Switch (ATS).

One of the pivotal components within modern generators is the generator control panel. This control panel serves as both the generator’s intelligence center and the user interface, allowing you to access and manage generator operations.

Many control panels incorporate an Automatic Transfer Switch (ATS) that continuously monitors incoming power. When the power level decreases or experiences an outage, the ATS sends a signal to the control panel, prompting the generator to start. Conversely, when incoming power is restored, the ATS instructs the control panel to shut down the generator and reconnect to the power grid.

Beyond round-the-clock monitoring, the generator control panel offers a wealth of information for site managers:

Engine gauges provide crucial details regarding oil and fluid levels, battery voltage, engine speed, and operational hours. In numerous generator sets, the panel can even automatically halt the engine if it detects issues with fluid levels or other aspects of generator operation.

Generator gauges supply valuable data on output current, voltage, and operating frequency.

What Kind of Generator Maintenance is Necessary?

Generators function as engines and thus necessitate routine engine maintenance to ensure optimal performance. Given that many generators serve as backup power sources during emergencies, it is imperative for operators to regularly inspect and maintain their generators to ensure they operate reliably when needed.

The ideal generator maintenance routine aligns with the manufacturer’s recommendations. At a minimum, all generator maintenance plans should encompass regular and routine tasks:

  • Inspection and replacement of worn components.
  • Checking fluid levels, including coolant and fuel.
  • Examination and cleaning of the battery.
  • Conducting load bank tests on the generator and automatic transfer switch.
  • Verification of the control panel for accurate readings and indicators.
  • Replacement of air and fuel filters.
  • Inspection of the cooling system.
  • Lubrication of parts as required.

Maintaining a comprehensive maintenance log is essential for record-keeping purposes. Include all readings, fluid levels, and other relevant information, along with the date and the generator’s hour meter reading. These records can be compared with future data, aiding in the early detection of abnormalities or operational changes that might hint at underlying issues, which, if unaddressed, could escalate into major problems.

With proper maintenance, generators can endure for decades. These simple yet essential investments pay dividends over time by averting costly repairs or the need for complete generator replacements. If in-house generator maintenance is impractical, many generator dealers offer maintenance contracts or can recommend qualified technicians to ensure your generator remains in peak condition year after year. It’s a wise allocation of time and resources, safeguarding your business’s continuity in the event of power outages.

Generator Maintenance

How Do I Size A Generator?

The foremost consideration when installing a backup or prime generator is getting the size precisely right. Undersized generators fall short in delivering the required power, necessitating selective allocation of power to electrical components. This can strain the generator, leading to mid-operation shutdowns, premature generator wear, and potential damage to connected devices.

Some might believe that installing a smaller standby generator is acceptable, reasoning that it won’t run continuously. However, this is flawed logic because, during an emergency, the standby generator must power the entire facility. In essence, a certain power capacity is essential whether the generator operates continuously or only in emergencies.

While it’s generally advisable to err on the side of a slightly larger generator, oversized generators also have drawbacks. Installing a generator with significantly more power than needed wastes resources. It results in higher initial costs, increased fuel and consumable expenses, and the risk of damaging connected devices.

Generators span a power spectrum, from 5 kW to 50 kW in the residential sector and from 50 kW to over 3 Megawatts in the commercial and industrial sectors. This extensive range offers choices but can be bewildering when selecting the right generator. The correct sizing involves multiple factors and considerations. To ensure accurate sizing, consulting a certified electrician is paramount. An electrician can assess your precise power requirements, evaluate your electrical system’s capacity and any necessary upgrades, and recommend the most suitable generator installation.

However, you can estimate your power needs by:

  • Compiling a list of all devices requiring power from the generator.
  • Recording the starting and running wattage for each item, usually found on the device’s identification plate or owner’s manual.
  • Calculating the total power requirements in kVA or kW. Some devices provide power requirements in amps, which can be converted to kW or kVA to determine overall power demands.


Once you have the facility’s total power requirements, you can procure a generator that aligns with your needs. Used and surplus generators offer cost-effective options while ensuring quality performance. Generators are robust and durable, so even well-maintained used units have plenty of operational life remaining. Reputable generator suppliers typically inspect these units for issues, review maintenance records, and make necessary repairs before sale. If you have a maintenance record and knowledge of the generator’s history, there’s no reason to shy away from used generators. Surplus generators, with minimal or no running hours, provide similar advantages, offering a cost-effective solution for your power needs.