Power resistor: all tests are go

Louise Smyth

Power resistor manufacturer, Cressall Resistors has completed the first phase of the extension to its research and development (R&D) facility. When fully complete, the expansion will allow Cressall engineers to carry out accurate and consistent lightning impulse and thermal power testing on electrical equipment. The facility will also have a dedicated test cell for Cressall's latest products, the EV2 water cooled resistor.

A 400kV impulse generator, which is used for dielectric and through impulse testing of Cressall's equipment has been installed and commissioned. Cressall has also fitted a power supply that will be used for thermal testing. To complete this stage, Cressall will install control gear to the supply as well as instrumentation and data logging capability. The build of the dedicated test cell for the EV2 product has also been completed ready for the installation of instrumentation and data logging equipment.

Cressall has also developed specialist software that records and accurately characterises lightning impulse test results. The software was developed by Damiano Natali, one of Cressall’s R&D engineers, which makes it unique to the resistor manufacturer.

With over 100 years of industry experience, Cressall has designed and manufactured a wide range of electrical resistor technologies for various applications. The expansion of the on-site R&D facility will allow the resistor manufacturer to extend its range even further by optimising and refining its product designs.

For customers, Cressall’s new R&D facility means testing time will be minimised and product delivery times will be brought forward. The company will have a back catalogue of product performance data at the ready and if any additional testing needs doing, it can be worked around the manufacturing process.

"One of the main reasons we decided to expand our R&D cell was the lack of facilities that had the appropriate equipment to test Cressall's EV2," explains Andrew Keith, engineering director of Cressall Resistors. "The specially designed EV2 test cell contains a temperature controlled water flow system, enabling us to test the EV2 under different power loads and water temperatures over long periods of time.

"Cressall is planning to do extensive tests on the EV2 water cooled resistor and collate the results for existing and new customers. This will give us a better insight into the extreme conditions the product can withstand."

The second phase of the expansion is currently underway, with the full development expected to be complete by summer 2016.