Cressall manufactures load banks ranging from small portable loads for testing petrol generators to multi-megawatt high voltage load banks for testing gas turbines and diesel generator testing at up to 13.8kV.
Regular load testing, along with correct battery maintenance, is the best way of ensuring the reliability of standby power systems.
Such tests are usually carried out against a temporary load bank brought to site for the purpose and removed afterwards, or a fixed dummy load bank installed with the generator.
Battery-backed uninterruptible power supplies (UPS) frequently form part of a standby power installation to provide power continuity while standby diesel generating sets are started. UPS batteries are a high-value asset and direct demonstration of their capacity in the form of a battery discharge test is a frequent requirement. Cressall offers a complete range of portable DC load banks for this purpose, with capacities of up to 240V DC and 600A.
Rail operators use 3MW load banks in their workshops for proving the power capability of the diesel engine — DC generator assemblies after they have been maintained or rebuilt. This requires a load bank such as the Cressall DC7000: this operates at up to 2kV and 8000A with fully automatic load selection and recording of test results.
As part of the testing regime for the new Royal Navy aircraft carriers Cressall have supplied a 17.225MW load bank
to load test the 11kV distribution system. The resistor was supplied as a naturally cooled system mounted on the dockside to minimise noise levels and save on auxiliary power requirements.
Most aircraft power supplies are 400Hz or 28V DC. Cressall manufactures load banks for load tests of such generators and Ground Power Units (GPUs). These include the DC800, which can simulate an aircraft engine start as part of the test.