A load bank is a very effective way to test essential power systems. It works by replicating a fully controllable load in a contained and organised environment, in contrast to the capricious and dispersed nature of the real load. By drawing its power from the supply unit it is testing, any issues or failures that may exist in the generator or other equipment can be identified and rectified.
Common load bank applications.
Though there are many more applications for a load bank, below are some of the more common uses.
- Load rejection assessment
- Checking that stand-by generator are functional
- New engine and new generator testing
- Removing wet-stacking issues caused by build up of unburned oil in a diesel generator
- Battery and UPS testing
Operating the load bank
Testing a generator with a load bank begins by turning the generator on and running it until the point that the water temperature stabilizes. All switches are then turned over to the emergency source and the unit will begin to receive step loads from the load bank until the desired load level has been achieved.
Types of load bank
The four types of load bank work in slightly different ways.
Resistive
The resistive is the most common type of load bank and is used mainly for small and portable generators and UPS. The resistive load bank provides an equivalent loading to the power supply allowing testing at 100% capacity. To assess load, it uses resistors to convert electrical energy into heat which then dissipates as water or air. Some larger load banks have an integrated blower incorporated for cooling while others depend on airflow from other sources such as an engine radiator. These type of load banks are available in a wide range of specifications including portable, trailer mounted and stationery, radiator cooled or water cooled and DC or AC options.
Reactive
Reactive load banks are applied mostly to loads that have an inductor or capacitor. They work by forming a magnetic field from a combination of reactive and inductive elements. Reactive load banks are suitable for testing motor-driven devices and transformers, usually those in the telecommunications industries.
Inductive
Inductive load banks are applied to commercial loads such as heating, lighting and transformers and can be combined with resistive load banks to provide full capacity testing. On their own, inductive load banks will only test to 75% capacity. They have an iron-core reactive element that when combined with the resistive load bank creates a lagging power factor load and provides accurate assessments of generators and conductors.
Capacitive.
These load banks are favourites for non-linear load testing of computer and telecommunications facilities such as data centres. As with inductive load banks capacitive models are often used in combination with resistive units in order to test a unit to 100% full power
Load banks are available in a wide variety of specifications. Talk to an electronic specialist like the RS Components team to find out which is the most suitable for your requirements.
