Contractor
Munich Airport GmbH

Our Services
Design planning
invitation to tenders
construction supervision

Starting Situation
Due to their many driving and control forces, aircrafts require a reliable continued supply of direct current.
Furthermore, every possible reduction of the total flying weight is desirable. If a higher voltage frequency is
used in operations, rather than the standard industrial 50 Hz alternating voltage, the iron weight of engines
and transformers can be reduced and the electrical energy can be converted more easily into constant
voltage. According to international standards (DFS 400), 200V/400 Hz alternating voltage is used to supply
aircrafts.

Normally, aircrafts get their electrical power from their own on-board generator, which e.g. is driven by an
auxiliary turbine. If the aircraft is on ground, it is supplied by a ground power unit.

Processing Time
1996

Result
For economic reasons, stationary 400 Hz power units with rotary transformers were chosen to be used at the
new Munich Airport. Each of the five central control rooms in the terminal were equipped with two rotary
50/400 Hz transformers, each having a ca-pacity of 250 kVA. The output voltage for the 960 V distribution
network is stepped down to the airborne power supply of 200 V by means of controllable step-down trans-
formers at each aircraft position.
Going beyond the intended purpose, the positions were designed for future jumbo jets.

A total of 11 central control rooms supply the following areas:
Passenger dispatch area
Freight area
Maintenance area

The freight area and the three maintenance areas have a separate supply network. The ramp positions,
located far outside are supplied by means of mobile ground power units.

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