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How to generator load bank testing?

How to generator load bank testing?  This test is a performance check that puts the generator under full load to verify its overall health and operation.

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In the world of power generation, it is vital to ensure the reliability and efficiency of your equipment. One way to accomplish this is through generator load bank testing – a process that sounds specialized but is actually quite simple.

How to generator load bank testing? This test is a performance check that puts the generator under full load to verify its overall health and operation. Not only does this help to identify potential problems before they become major issues, but it also ensures that your generator will be able to meet the demand for power when you need it most.

In today’s blog, BISON generator suppliers going to dive into the specifics of how to perform a generator load bank test. So if you’ve ever wondered about specific ways to ensure optimal generator performance, buckle up – you’re in for a treat!

Basics of load bank testing

Load bank testing is a critical process that tests the generator’s ability to produce maximum output in terms of amps and voltage. It reveals potential problems within the generator system that may not be noticeable during light loads or no-load conditions. Load bank testing ensures that our generator will work as expected when the power goes out.

how to generator load bank testing

types of load banks

Each type of load banks serves a specific purpose and helps paint a complete picture of a generator’s health and readiness. By understanding how these work, you can ensure your generator will perform when you most need it.

  1. Resistive Load Banks: The most common type, these apply a load to the engine and alternator, similar to what would occur under normal operational conditions. Resistive load banks are typically used for testing at 100% of the generator’s full kilowatt (kW) rating.

  2. Reactive Load Banks: These are used to simulate the lagging power factor of commercial loads and are used in combination with resistive load banks. Reactive load banks test the kVA (kilovolt-ampere) rating of a generator, rather than just the kW rating.

  3. Inductive Load Banks: A type of reactive load bank, these create a lagging power factor load. They are commonly used in combination with resistive load banks to simulate mixed commercial loads consisting of lighting, heating, and motor loads.

  4. Capacitive Load Banks: These are used to create a leading power factor load. This type of load bank is primarily used for testing generators that will be used for certain types of electronic or non-linear loads.

connecting to a circuit breaker

The Load Bank Testing Process

Understanding the Load Bank Testing process is crucial to ensure the reliability and longevity of your generator. The process can be broken down into three main stages: Preparation, Testing, and Post-test Inspection.


Before you dive into testing, proper preparation is essential:

  1. Select the Correct Load Bank Type and Size: Based on the type and capacity of your generator, select an appropriate load bank. The load bank should be capable of loading the generator to its full kilowatt or kilovolt-ampere rating.

  2. Disconnect the Generator from the Load: To prevent any unforeseen issues or power interruptions, disconnect the generator from the load it normally serves.

  3. Connect the Load Bank to the Generator: Ensure that the load bank is correctly connected to the generator as per the manufacturer’s instructions.

  4. Warm-up the Generator: Start the generator and allow it to reach its normal operating temperature before applying any load.

generator connected to load box


Once you’ve prepared, you can proceed to the actual testing:

  1. Apply Load in Increments: Start by applying a small load to the generator, gradually increasing it until the generator is operating at 80-100% of its rated capacity.

  2. Monitor Performance: Throughout the test, monitor the generator’s performance parameters such as voltage, frequency, amperage, and temperature. Any anomalies could indicate potential issues.

  3. Reduce Load and Disconnect Load Bank: If the generator performs satisfactorily under full load, gradually reduce the load, let the generator cool down, then disconnect the load bank.

Post-test Inspection

After the test, some post-test procedures need to be followed:

  1. Inspect the Generator: Check for signs of damage or wear. Look for any leaks, unusual noises, vibration, or other irregularities.

  2. Record the Test Results: Record all data and observations for future reference. This will help track the generator’s performance over time.

Safety Considerations

Safety should always be paramount during load bank testing:

  1. Qualified Personnel: Only trained and qualified personnel should perform generator load bank testing to prevent accidents or damage to the equipment.

  2. Use of Personal Protective Equipment (PPE): Always use appropriate PPE, such as gloves and safety glasses, when working with generators and load banks.

  3. Follow Manufacturer’s Instructions: Abide by all safety precautions provided in the manufacturer’s instructions. This includes maintaining a safe distance from the load bank during operation due to the heat generated.

By following these steps, you can effectively conduct a generator load bank test, ensuring your generator is ready to perform when it’s needed most.

generator load test in progress

Why Generator Load Bank Testing?

Performing a generator load bank test is a critical procedure that ensures your generator will perform optimally when it’s needed the most. The process involves applying a simulated load to a generator, gradually increasing until it reaches its full operating capacity. This helps to identify any potential issues that may not be apparent under normal or no-load conditions.

benefits of conducting a generator load bank

Load bank testing a generator is a vital procedure that ensures your power system’s reliability and longevity. It helps to identify and rectify potential issues before they become serious problems, ensuring that your generator is always ready to perform when you need it.

  1. Preventing Wet Stacking: Generators that frequently run at less than their full load capacity can suffer from a condition known as wet stacking. This occurs when unburned fuel deposits in the exhaust system, leading to decreased performance and potential damage. Load bank testing helps to burn off these deposits, thereby preventing wet stacking.

  2. Verifying Total System Operation: Load bank tests verify not only the generator’s performance but also the correct operation of the transfer switch, circuit breaker trips, and engine control system. It’s a comprehensive test of your entire power supply system.

  3. Identifying Potential Problems: By pushing the generator to its maximum capacity, load bank testing can reveal issues that might go unnoticed under lighter loads. These could include problems with the fuel system, cooling system, or alternator.

  4. Maintaining Battery System Performance: During a load bank test, the battery charging system is also under load, which can help to identify potential deficiencies in the battery system.

  5. Providing Assurance: Load bank testing gives you peace of mind that your generator will work as expected in an emergency. You can be confident that your generator will be able to handle the load when it’s most needed.


Generator load bank testing is an indispensable process in ensuring the optimal performance and longevity of your generator. BISON generator suppliers will take you through the intricacies of the process, from explaining the concept of load bank testing to detailing the different types of load banks such as resistive, reactive, inductive and capacitive load banks.

BISON also walked you through the step-by-step process of conducting a load bank test, which includes preparation, testing, post-test inspection, and important safety considerations. Each step is crucial in ensuring the test’s effectiveness and maintaining the safety of the personnel involved.

In conclusion, regular generator load bank testing is an investment in reliability. It gives you peace of mind knowing that when the time comes, your generator will be ready to perform at its best.

How to generator load bank testing FAQ

A generator should typically undergo load bank testing once a year. However, if your generator doesn’t often run at full capacity, or if it’s primarily used as a backup power source, you might want to consider testing it more frequently.

To size a load bank for generator testing, you should match or exceed the generator’s maximum output capacity. This means if your generator’s rated output is 100kW, your load bank should also be able to handle at least 100kW. This allows you to fully test the generator at 100% of its rated capacity.

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