What is a load bank?


A load bank is a piece of equipment that tests an uninterruptible power supply (UPS) by replicating the load that is produced by power supply units.  During the testing process, the load bank will identify any faults or potential interruptions allowing corrections before a power outage occurs.  Load banks test load, electrical, mechanical and voltage by pulling all controls and systems into one unit, using the power supply as its energy source.  Common applications are generators, battery systems, ground power units and wind generators.

When are load banks used?

Load banks are used to test both new and old equipment.  Engine manufacturers will use a load bank to put a new engine through its paces, trying out a variety of mechanical loads and testing performance.  Standby generator manufacturers also use a load bank to measure the endurance and stability of each unit and to calibrate the generator to ensure it meets the expected tolerance and specifications.  

Load testing is commonly applied to generators in the field to ensure they are maintaining performance.  This is vital to ensure plants, pumps and mining operations are not interrupted by power shut downs.  Wet-stacking or the build-up of grease and oils can occur in diesel generators and affect performance – a load bank test will be able to identify and prevent this from happening in any of the units.  

Load bank categories

Different types of load banks are applied to suit the type of supply being tested.  

Resistive load banks

Resistive load banks simulate real life resistive loads and are most suited to portable and small generators and UPS.  They operate by converting electrical energy to heat, which is then dissipated by convection or forced means.  The resistive load bank provides an equivalent loading to the power supply.  Resistive load banks come in multiple sizes and power levels and are available as either portable or rack mounted. 

Reactive load banks

Reactive load banks simulate systems of motor-driven equipment, transformers and other electromagnetic equipment found on a power network.  They operate by converting the electrical current to a magnetic field using an inductor or capacitor.  Reactive and resistive loads are also found in combination units.  

Inductive Load Banks 

An inductive load bank is applied for simulation of real-life combined commercial loads which include heating, lighting, transformers and engines, for example.  Individually these load banks will only test up to 75% of full power, and they are often used in combination with resistive systems to provide full power testing. 

Capacitive Load Bank

The capacitive load bank also stimulates power supplies and applications, however these load banks employ capacitors containing two conductive surfaces divided by an insulator to retain potential energy in an electrical field.  Capacitive load banks are often employed at research institutions to evaluate newly developed power systems.   They are becoming more commonly used in industry with the inclusion of complex electronics in equipment and machinery. 

To go for more detailed information about the right load bank for your equipment, head to RS Components to learn more.


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