Solid-State 400Hz Ground Power Unit / Static Frequency Converter (40-144 kW), made by MAK Controls & Systems

The MAK Static Frequency Converter (SFC) is a solid-state ground power unit that takes standard utility mains — 400/415V three-phase at 45–65 Hz — and converts it to the 400Hz, 200/115V three-phase power that aircraft avionics and systems require. Unlike diesel-driven GPUs, it produces no exhaust, consumes no fuel and operates quietly, making it the correct solution for fixed-gate installations at terminals, hangar bays, PBB-integrated gates and electrified apron stands. The range covers 40 kW to 144 kW output, sufficient for single-aisle aircraft up to wide-body type support. Conversion efficiency runs 87–95% across the load range; active power factor correction (APFC) holds input power factor at unity from 25% to 150% load, minimising reactive current demand on the airport electrical supply. Output voltage regulation is within ±1% across the full 0–100% load range; dynamic voltage recovery from a 5% disturbance completes within 40 milliseconds — comparable to or better than diesel-driven units. Total harmonic distortion at the output is below 2% at linear load, protecting aircraft avionics. The overload envelope — 150% continuous, 200% for two seconds — accommodates the inrush currents that aircraft loads present at energisation. No-break power transfer capability allows seamless hand-off between SFC and pit-power sources without interrupting aircraft bus power. Noise output is below 65 dBA at one metre, meeting indoor terminal and overnight-maintenance requirements. The unit is available in fixed-installation, trailer-mounted and jet-bridge-integrated forms. IP54 enclosure and a -20°C to +55°C operating range with no de-rating to 2,500 m altitude make it suitable for high-altitude regional airports as well as sea-level Gulf hubs. CE certified.