Load Bank Rentals     

A load bank is a device which develops an electrical load, applies the load to an electrical power source and converts or dissipates the resultant power output of the source.

The purpose of a load bank is to accurately mimic the operational or “real” load that a power source will see in actual application. However, unlike the “real” load, which is likely to be dispersed, unpredictable and random in value, a load bank provides a contained, organized and fully controllable load.

Consequently, a load bank can be further defined as a self-contained, unitized, systematic device that includes load elements with control and accessory devices required for operation.

Whereas the “real” load is served by the power source and uses the energy output of the source for some productive purpose, the load bank serves the power source, using its energy output to test, support or protect the power source.

Applications

Load banks are used in a variety of applications, including:

• Factory testing of turbines and engine diesel generator sets
• Reduction of wet stacking problems
• Periodic exercising of stand-by engine generator sets
• Battery and UPS system testing
• Ground power testing
• Load optimization in prime power applications
• Removal of carbon build-up on piston rings

[edit]Load bank types

The three most common types of load banks are resistive, inductive, and capacitive. Both inductive and capacitive loads create what is known as reactance in an AC circuit. Reactance is a circuit element's opposition to an alternating current, caused by the build up of electric or magnetic fields in the element due to the current and is the "imaginary" component of impedance, or the resistance to AC signals at a certain frequency. Capacitive reactance is equal to 1/(2⋅π⋅f⋅C), and inductive reactance is equal to 2⋅π⋅f⋅L. The unit of reactance is the ohm. Inductive reactance resists the change to current, causing the circuit current to lag voltage. Capacitive reactance resists the change to voltage, causing the circuit current to lead voltage.

[edit]Resistive load bank

A resistive load bank, the most common type, provides equivalent loading for both generators and prime movers. That is, for eachkilowatt (or horsepower) of load applied to the generator by the load bank, an equal amount of load is applied to the prime mover by the generator. A resistive load bank, therefore, removes energy from the complete system: load bank from generator—generator from prime mover—prime mover from fuel. Additional energy is removed as a consequence of resistive load bank operation: waste heat from coolant, exhaust and generator losses and energy consumed by accessory devices. A resistive load bank impacts upon all aspects of a generating system.

The “load” of a resistive load bank is created by the conversion of electrical energy to heat via high-current resistors such as grid resistors. This heat must be dissipated from the load bank, either by air or by water, by forced means or convection.

In a testing system, a resistive load simulates real-life resistive loads, such as incandescent lighting and heating loads as well as the resistive or unity power factor component of magnetic (motors, transformers) loads.

The most common type uses wire resistance, usually with fan cooling, and this type is often portable and moved from generator to generator for test purposes. Sometimes a load of this type is built into a building, but this is unusual.

Rarely a salt water rheostat is used. It can be readily improvised, which makes it useful in remote locations.