Chapter One
1 - 6
Load Bank Applications
The main application for a load bank is usually generator testing. However, load banks are
versatile devices and they have a number of useful applications that can be applicable
including data centre Heating Ventilation Air Conditioning (HVAC) testing and UPS
testing.
Generating set testing
The specific tests that need to be carried out for a particular installation depend on local
regulations, the application, the type of equipment involved and the requirements of
insurance companies, local authorities and other interested parties.
The requirements for the testing of engine driven generators are described in ISO 8528
part 6. This document explains the general test requirements and describes both a
functional test and an acceptance test. Functional tests must always be done and usually
occur at the manufacturer’s factory. Acceptance tests are optional and are often done on
site, witnessed by the customer or his representative.
ISO 8528 part 5 defines three performance classes - G1, G2 and G3, each with different
criteria:
•
G1 is the least stringent and applies to small generating sets intended to supply simple
loads.
•
G2 is broadly equivalent to commercially available power.
•
G3 is intended for sets which are powering loads which particularly require a stable
and accurate power supply.
A further class, G4, allows for performance criteria agreed between the supplier and the
buyer.
In addition to the testing that is carried out immediately after installation, it is important
to carry out regular tests as part of an ongoing maintenance program. This is particularly
important for emergency power supplies that may have long periods of non-operation.
The type of tests carried out include:
•
Load duration tests (also known as a “heat run”), designed to record steady-state
voltages, frequency, and also to calibrate instrumentation and measure emissions and
fuel consumption.
•
Load acceptance tests, which check changes in frequency and voltage regulation due
to sudden load changes. These tests ensure that the rise and fall of the generator’s
output voltage and frequency remain within limits as load is applied and removed.
Note:
The specific
details regarding the
frequency and type of
test required may also
be specified by local
regulations or other
interested parties.
Introducing ASCO Load Banks
1 - 7
Testing UPS systems and batteries
Uninterruptable power supply systems consisting of a generating set combined with a set
of batteries are a common feature of data centres and other installations where maintaining
a constant power supply is critical. In the event of a power failure the batteries provide an
immediate source of power whilst the generator is automatically started, synchronised to
the correct frequency and put online.
Regular testing of the batteries, generator and its automatic control gear is extremely
important, but testing using the site load could put critical systems at risk and may not
provide sufficient load for a complete test. Load banks provide an ideal solution because
they will allow the operation of the UPS to be fully tested without posing any risk to the
site load.
Data centre HVAC testing
Heating, ventilation and air conditioning (HVAC) systems are vital in providing cooling to
server racks within data centres. The HVAC system must be able to maintain a constant
cool temperature when the servers are working at full capacity. Load banks are a cost
effective method of simulating heat produced by the servers. Operators can analyse how
the HVAC system copes with the temperature rise, without risking the vastly expensive
server racks over heating.
