Load Bank Testing

Load bank testing is the best way to measure the performance of your generator set. It can reveal problems in your generator set so they can be corrected before your system is called on in a critical emergency. Stowers’ generator technicians can test your power system under simulated operating conditions to ensure that it will perform when needed.

What is Load Bank Testing

A load bank is a self-contained load source sized to exercise both the engine and generator in order to ensure proper performance of the generator set as a system at rated load.

Load bank testing is an important component of an emergency power system’s maintenance program and should be a scheduled part of the maintenance plan. Load bank testing provides proper loading of the emergency system and a record of the system’s fitness, and can identify needed repairs before they render the system unusable in an emergency.

Reasons to use a Load Bank

Load bank testing is perhaps the best way to measure the performance of your generator set. It can reveal problems in your system so they can be corrected before the system is called on in a critical emergency.

When sizing a generator system, engineers typically oversize. There are a couple of reasons for this. The capacity for future load growth may be a requirement, or the load profile may include some loads that need more generator capacity for initial starting. While these practices are acceptable, a diesel engine that has been oversized to accommodate these factors may not be able to achieve loading adequate to clean deposits formed by the fuel in the engine. These deposits often lead to a condition known as “wet stacking.” This condition can be observed as seepage from the exhaust section of the engine, including the turbo and exhaust manifolds. The buildup of these deposits also occurs in combustion chambers, fuel nozzles, piston rings, and exhaust silencers. These deposits can destroy an engine.

A diesel engine should operate for an extended time at loads that will produce exhaust temperatures that meet the manufacturer’s minimum recommendations. This helps rid the engine of deposits and helps keep the exhaust clean, lessening its impact on the environment.

Load Testing Schedule

Typically, engine generator sets are tested on a weekly basis. Often, this is done with no load and is done primarily to ensure that the system will start and come to full frequency and voltage when called on in an emergency. Automatic switching is also tested during this exercise. The down side of this procedure is that the system is usually run for only about 30 minutes per week and doesn’t have a chance to reach its rated output or the exhaust temperature that will properly clean deposits that may have built up in the system.

When inspecting the engine, look for signs of seepage at the exhaust manifold and turbocharger “hot side” joints that may indicate problems. If you have questions, schedule our staff to come for a visit to determine if your engine needs attention. Stowers technicians can recommend ways to address any potential problems and can suggest the best way to develop a load testing schedule that is appropriate for your generator set.

Concerns about Load Bank Testing

If an engine has not been properly loaded for some time, either because it has not been load bank tested has carried only light loads, it is possible to damage the engine during initial load bank testing. Built-up deposits can break free and cause damage to internal parts of the engine. Therefore, we recommended that only an authorized technician be allowed to conduct your load bank test, and only after careful evaluation of the engine’s condition.

While your load bank test is underway, your facility should be disconnected from the emergency generator system. Therefore, during the test, your emergency power system cannot support the loads in your facility. If you emergency power system provides power to life support systems or other mission-critical applications, special planning may be required to minimize the risk to your organization.

Want to Know More?

Contact your Stowers Power Systems product support sales representative for more information on how load bank testing from Stowers can help ensure that your power system will supply you with continuous power when it is needed.