A load bank is a device that generates a prescribed amount of electricity draw to test the reliability of electrical switching, generator output, uninterruptable power supply (UPS) systems and cooling in a data center.
Rack-mount server-simulating load banks discharge heat while consuming power to accurately mimic the load of a server processing a workload. Data centers test cooling and power supply operation with load banks rather than software simulations for more real-world accuracy, such as air-flow blockage in the rack caused by the server-sized load bank, or dust in the air from improper filtration. Avtron, ComRent and Mosebach are server simulator load bank manufacturers.
A load bank test simulates real operation by applying the load in situ, with real temperatures and relative humidity, but it is not an exact reproduction. The load bank only draws power (current and voltage) to test the infrastructure, and then dissipates it safely as heat.
Load banks are either portable or fixed. Fixed load banks suit outdoor use, while portable load banks can move around the data center and between sites to test specific power setups.
Load banks cannot mimic the random peaks and lulls of real data center equipment power usage, but they can approximate the equipment's requirements in a controlled setting with high levels of accuracy.
Load testing should be included on UPS maintenance schedules. Capacitive load banks, or capacitor banks, commonly test UPS and other electronic loads by creating a leading power factor. Some power supply vendors, such as Emerson Network Power and Power Systems Specialists, offer load bank testing as a service.
Inductive load banks, by contrast, create a lagging power factor. The third common load bank type is resistive, with a lagging power factor. Resistive load banks, used frequently for industrial purposes, provide equivalent loading on the generator, and are usually portable.