Load bank testing is a key part of a comprehensive maintenance program. Either annually or on a one off basis the load bank will test both the engine and alternator at varying loads up to a maximum load. Typically the length of the testing is between of 2-4 hours duration.
The generator is connected to an electrical load that provides an adjustable electrical resistance, or resistance and reactance to simulate the actual electrical load of the generator. This facility is especially important when operational restrictions limit the opportunity for testing standby generators on light on no-load conditions. The diesel engine in particular can be affected from periods of running on low electrical loads.