R-28 Series 28.5 V DC Rectifier

The R-28 Series is CDR Technology's dedicated DC ground power unit, purpose-built to supply the 28.5 V DC bus that drives starters, flight-deck avionics, emergency systems, and APU assist circuits on turbine aircraft and helicopters. Where APU fuel burn during long turns is a cost and emissions concern — increasingly regulated at GCC hubs — a DC GPU such as the R-28 provides the cold-start energy without burning jet fuel on the ramp. The headline specification is output current: up to 1,600 A continuous with a 2,500 A overload capability for engine cranking. This overload headroom is the critical figure for ground engineers; aircraft starter motors draw sharp inrush current that cheaper rectifiers cannot sustain without voltage collapse, which aborts the start and delays departure. Multi-channel variants offer two independent DC outputs, allowing simultaneous servicing of the aircraft's main bus and an isolated avionics or emergency circuit, or powering two light helicopter positions from one cabinet. CDR's emphasis on field serviceability is notable: the modular architecture is designed for fault isolation and card swap in under ten minutes, keeping mean time to repair low in remote or short-staffed stations. Acoustic output is held below 65 dB(A) at one metre — relevant inside enclosed hangars and at night-hour positions near passenger terminals. Voltage modes extend beyond standard 28.5 V to 28, 48, and 56 V, which broadens applicability to military platforms, UAV ground stations, and specialist maintenance equipment. An integrated energy-monitoring and 'black box' logging function supports maintenance records and energy-cost accounting.