A load bank imitates the electricity used by a power source (such as a battery or generator) to test the efficiency of that source. It develops the electrical load, applies it to the source, then dispels it, with the primary goal of ensuring commercial and industrial operations have quality power at all times.
Load banks are used for:
- Exercising generators for engines
- Testing ground power
- Optimising loads
- Wind turbines
- Rejection testing for loads
There are four main types of load banks.
Resistive Load Banks
The most common type of load bank, resistive load banks are used when the power supply and the engine are loaded equally. It mimics a capacitive load and draws it from the generator, depleting the entire generating system of its stored energy and converting the system’s electrical energy into heat, which is then used to generate the load. It draws this power demand, measured in kW, from the generator in order to keep the cooling system, exhaust system, and engine running.
Resistance load banks are generally portable, though they can be installed permanently if necessary. Their portability, however, allows them to be used sequentially on a range of different generators. A fixed resistive load bank also has a shorter lifespan and costs more to repair and replace.
This type is generally used to test generators with a capacity of less than 200 kW, small and portable generators and UPS systems.
Reactive Load Banks
Reactive load banks can simulate both inductive and capacitive loads:
Inductive Load Banks (lagging power) provide a reactive load to create lower power loads. They simulate mixed loads at a ¾ capacity of the resistive load and simulate the “real” conditions of operation. So for every 100KW of resistive load, 75KVAR of inductive load is achieved.
Capacitive Load Banks are similar, but create leading power loads rather than lagging. They are generally used with non-linear loads in industries that require an uninterrupted power supply (such as data centres).
Reactive load banks are ideal for testing transformers and motor-driven devices. They’re common in the UPS and telco industries.
Combined Load Banks
These have elements of both resistive and reactive load banks, incorporating resisters and inductors in the construction (some also include capacitive). They can be switched to resistive only, inductive only, or they can provide varying lagging testing.
Electronic Load Banks
Electronic load banks are becoming more commonplace since the accuracy and sophistication exceeds other types. Though they are more expensive, electric load banks can be used in a range of applications – and they are automated and programmable. With this style, the electric load is applied to the power source and it can test for both average and peak capacities.
Electronic load banks are mostly used in healthcare, aviation, transport, telecommunications, and mining.
The type of load bank for your clients or your business depends on a range of factors, so make sure you do your research to determine which is the best option. You’ll find a variety of affordable, reliable, efficient, and environmentally-friendly options.