Smiths Aerospace is a major supplier to manufacturers of military and commercial aircraft, spacecraft and ground vehicles around the world. It designs, develops and manufactures equipment such as electrical power systems, vehicle management systems, data management technology and in-flight re-fueling systems. A key aspect of the work is testing at all stages to appropriate international standards.
Helping to fulfill these test requirements, to such standards as MIL-STD-704F and SAE AS5692, are three load banks from REO UK. Two are currently employed on projects for the Joint Strike Fighter (JSF) while the third is being used to help with the development of a new solid state circuit breaker for the aircraft industry to facilitate electrical fault detection.
According to Steve Curwen, JSF EPMS Systems Team Leader for Smiths Aerospace, the two REO load banks enable his team to test the various systems under development at high power and high voltage. The third unit, which is, in fact, three units in one, was designed to support the development of arc fault protection and verify aircraft circuit breakers performance.
The two load banks used on the JSF programs, which are rated at 9.36kW, are used at nominal voltages of 28VDC and 270VDC, but offer maximums of 60A and 400VDC respectively with peak load currents of 25A at 350V and 50A at 35V.
The third unit provides a variable load bank for a variable voltage power source used in conjunction with specialized arc generation equipment and a 'desk top' rapid electrical fault identification development system. Resulting algorithms are considered to be essential for helping to maintain the 'health' of aircraft, particularly with the move towards the all electric aircraft.
"Engineered especially for us by REO," said Mike Bailey, Program Manager, Aircraft Systems Prognostics and Health Management (AEPHM), "this load bank offers three different voltage options: 28VDC, 115VAC and 270VDC. Normally three separate units would be required but this one permits us to select the appropriate voltage via a switch. The space saving is also a major bonus for us. "
Algorithms resulting from the tests performed will facilitate detection of arc faults, such as parallel faults between adjacent cables arising through insulation breakdown due to chaffing / abrasion, loose connections giving rise to intermittent supply interruption when aircraft experience vibration, and shorting promoted between damaged cables by to electrolyte.