Static converters for urban vehicles auxiliary power supply assures the DC consumer supply, AC consumers as well as tram or trolley bus battery charge.

The advantages of static converters using:

• - low energy consumption,
• - big reliability,
• - easy maintenance at reduced costs,
• - easy integration in the circuit diagram,
• - modular structure and reduced weight.

Static converters work as being integrated in an adequate circuit diagram, suitable to their role in the vehicles driving assembly.

The static converters produced by INDAELTRAC can be used both for trams and trolley buses initial equipping and for the updating of vehicles in use.

The static converter is connected to the supply mains by the circuit mains connectors to the control received at the board.

Between the supply line and the DC or AC outputs there are two galvanic insulation steps, for the trolley bus, but there is only one insulation step for the tram assured by the insulating transformer.

Static converters are built with modern electronic components: IGBT transistors, ultrarapid diodes, filters, transducers.

In the main, the bloc diagram of a static converter includes:

• - input filter
• - decreasing chopper
• - monophase inverter
• - insulating transformer
• - rectifier and DC voltage regulator

Current and voltage transducers together with the adequate regulators belonging to the control unit, maintain voltage and current at the prescribed values. During the converter operation are monitored the following signals:

• - line tension
• - current of transformer main circuit
• - DC tension (28 Vdc)
• - batteries charge current
• - total current of tram or trolley bus DC consumers