December 08, 2017

SNCF trials Japanese traction transformers

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An SNCF T4 tram-train in Paris. An SNCF T4 tram-train in Paris.

FRENCH National Railways (SNCF) has awarded a contract to Mitsubishi Electric to supply prototype traction transformers for Z2N EMUs and T4 tram trains operating in Paris.


SNCF requested Mitsubishi Electric to lower the weight of the Z2N’s traction transformer and to reduce energy consumption and noise as part of the refurbishment of these trains, while extending the life of the T4’s traction transformer.

As a result, Mitsubishi Electric says the prototype traction transformer weighs 1950kg compared with 2350kg for the Z2N’s existing transformer thanks to its aluminium winding cables, yet its conversion efficiency is the same or better than the existing equipment. The interface design is identical with that of the existing equipment, so the cars will not require modification.

Mitsubishi Electric claims the traction transformer for the T4 tram-train is the world’s first application of a natural-running air-cooling traction transformer on the car roof. This should reduce noise by around 13dB by omitting the electric cooling fan, and reduce electricity losses by 50%.

Fully-hermetic constant-pressure bellows seals will eliminate the need to periodically replace the insulator oil, which remains in a sealed system so it will not deteriorate. As a result, overall maintenance costs should be reduced.

The traction transformers for the Z2N will be delivered in February and those for the T4 vehicles in December 2018. Once installed, the transformers will be evaluated for one year. If all goes well, SNCF will draw up mass-production specifications for both traction transformers, and Mitsubishi Electric hopes to win orders from tenders for both products. Mitsubishi Electric says it is the first Japanese company to be certified by SNCF as a propulsion systems supplier.

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