railway company Deutsche Bahn AG, selected SR Drive® powered
air-cycle air conditioning for its latest ICE 3 high speed
passenger trains. The move to aerospace HVAC technology
comes in response to growing concerns over the environmental
impact of chemical refrigerants.
efficiency SR Drive® switched reluctance
motor drives air cycle system.
SR Drive® motor
and compressor unit
Air-cycle air conditioning is based on the
simple concept of cooling air by forcing it to expand as it
passes through a turbine. In
response to growing concerns over the environmental impact of
chemical refrigerants, air-cycle systems have been applied into
the railway market to meet today’s growing demand for environmentally
friendly, reliable and easily maintainable air conditioning equipment. In
aircraft, air conditioning is powered by compressed air bled
from the engines, however in a train, a high efficiency SR Drive® motor
drives a compressor to provide the source of air.
Air is compressed in two stages,
firstly by the SR Drive® motor
compressor and then by the compressor side of a cold air unit. The
same air is continually cooled and returned around the circuit,
transferring its cooling effect via heat exchangers into the
The variable speed SR Drive® motor
provides a soft start for the system and precisely matches the
thermal load of the train carriages. At maximum cooling,
the motor power is 40kW at a speed of 23,000 rev/min.
The unit is operated from a 670Vdc power converter and weighs
less than conventional air conditioning, allowing it to be entirely