Currently the EC/IC day coaches of German railways are being totally upgraded and modernised.

They will get a new interior design and passenger information systems. Eight-six coaches will be equipped with a new multi-voltage power supply system from SMA. The bistro coaches allocated to these will also be redesigned in the Delitzsch factory of German railways, five of them will get the SMA multi-voltage power supply system MEE-NT. For another seven service coaches of DBAutoZug SMA will deliver the MEE-NT in an identical design.
The MEE-NT multi-voltage power supply with 75kW total power is used to supply consumers in the kitchen, air conditioning and other consumers. This system consists of an electrically separated input unit for multiple-voltage operation with a maximum voltage of 5kVdc, an 18kW battery charger (GVG) and a 69kVA three-phase inverter with a fixed output frequency of 50Hz. The air-conditioning three-phase inverter was integrated into the container of the existing air conditioning system as a separate device. It is also suitable to upgrade single-voltage bistro coaches without MEE-NT.
In addition to the usual connection module a high-voltage module with the input contactor for the MEE-NT is integrated into one of the underfloor containers. Thus SMA has solved the problem of scarce space available underfloor. The area is partitioned off from the rest of the container where the low-voltage components are placed. It can only be accessed via a separate container door.
Specially for the bistro and service coach the MEE-NT was equipped with a special three-phase inverter with transformer module to supply the Galley cooling systems. In normal operation the three-phase inverter with nominal power of 6kVA is fed from the intermediate circuit and supplies 3x230V50Hz. If the train bus fails the three-phase inverter is supplied with 120Vdc from the battery network in emergency operation. It will continue to supply the required output voltage with limited power.
Delivery of the power supply system for bistro and service coaches includes a diagnosis system for easy monitoring of the system without having to open the underfloor container. Operating states, failure messages, event and history memories can be seen and read on screen. The interface to the power supply consists of a card which also allows to connect a service laptop. Data can be read out via this interface for further evaluation.
SMA also took over the engineering to upgrade and modernise the electrical equipment of coaches and adjust it to the new MEE-NT. The upgrading instructions are an additional planning tool for the factory performing the rebuild. The usual engineering documents such as circuit diagrams, lists of components and wiring diagrams were created by SMA's experienced engineering staff who also created the documents for the Metropolitan and the LIREX.

Enquiry No 33

SMA Regelsysteme GmbH is based in Niestetal, Germany. www.sma.de