Introducing Froment Load Banks
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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.
Site load correction
In many applications a generator may be required to run for extended periods with little or
no load applied. For a diesel generator this may mean that the engine does not reach its
optimum operating temperature and this can cause a problem sometimes known as “wet
stacking” – so called because unburnt fuel can make its way through to the exhaust stack.
This can lead to serious maintenance problems, including high levels of cylinder wear,
excessive fuel consumption and high levels of emissions.
Froment load banks provide a function known as Site Load Correction (SLC) which provides
an automated solution to this problem. This is where the load bank automatically adds and
removes load to keep the generator running at an optimal temperature.
There are many applications for Site Load Correction. Figure 1-10 shows an example
scenario where a site that is usually supplied by the public utility supply makes use of a
backup generator. The system is designed so that, if the utility supply fails, the generator
will start up and supply power to the site until the utility supply is restored.
