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Load Bank Testing

The purpose of an emergency generator set is to provide a reliable source of power to your facility or commercial operation during an emergency situation when power from the grid is suddenly lost or is not available. In the event of a power failure, you should have peace of mind that your backup power source will kick into action on a moment's notice. But what happens when the power goes out and your genset does not function as expected? The result can often be costly and sometimes catastrophic.

This is precisely the reason generator load bank testing is a vital piece of a comprehensive preventative generator maintenance plan, which you should  have conducted on your genset(s) each year. Load bank testing helps to ensure that your generator will be fully dependable and operational, as well as completely capable of the handling the load it may be required to handle at any point in time.

What is Generator Load Bank Testing?

A generator load bank test involves an examination and assessment of a genset.  It verifies that all primary components of the generator set are in proper working condition under loaded conditions. The equipment used to conduct a load bank test applies a load to the genset, allowing the engine to reach the same normal operating temperatures and pressures it would need to maintain during an actual event.  This is especially important for standby and emergency generator sets that do not run very often and/or may not be exposed to carrying heavy loads on a frequent basis.  The general rule is - if your generator is not exposed to higher than 30% of its rated kW load then you should be considering a load test.

A load bank test ensures that your generator will run properly when it’s needed, and that you can fully depend on it during an emergency situation. The key to a proper load bank test is that it tests your generator at its full kilowatt (kW) output rating. Because many generators do not regularly operate at their full kW rating, it's important that you verify your generator can actually produce the rated output - while at the same time maintaining adequate temperature and pressure levels that will allow it to run as long as necessary.

How does a Load Bank Test Work?

When a load bank test is implemented, a simulated load is applied to the generator. The test is timed and gradually increases the kW load in specific increments. Each time the kW load is increased, engine and alternator parameters are recorded. This tests the generator's ability to continue functioning at the full rated output for a sustained period of time.



When a diesel engine powered generator is not used frequently or only run on light loads, unburned fuel and soot buildup in the exhaust system. This is called 'wet-stacking.' When wet-stacking occurs, the genset is likely to perform poorly, to endure damage, can become a fire hazard, and can even lead to complete failure. During a load bank test, the generator is allowed to run at full power and full temperature. This will cause any build up to burn off. For a diesel unit, load bank test actually serves two purposes: 1) it tests the generator to ensure it will function properly and efficiently on all levels; and 2) it eliminates wet-stacking.

Benefits of Load Bank Testing

There are multiple reasons gensets should undergo a load bank test on an annual basis, including the following:

• Verifies the genset is capable of handling it's full rated load.
• Problems discovered early can be less expensive and prevents future issues.
• Helps to avoid wet-stacking and cleans out carbon deposits.
• Verifies the engine cooling systems will perform while under load.
• Provides assurance that the genset will work properly when you need it most.

Contact Gentrak today to schedule your next Load Bank Test!


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