Munich – Schaltbau, located in Munich, has developed a new voltage and frequency analyser. It allows for the automatic adaptation of high-voltage loads of passenger coaches and freight cars to the four different European UIC voltages in cross-border traffic. The device detects a change of voltage, switches over to the new supply voltage and checks the grouping of the electrical loads.


The new ZH1114 series voltage selector meets the requirements of today’s cross-border railway traffic. It measures and analyses the voltage and frequency of the power supply fed to the train line and generates the proper configuration and corresponding control signals which operate the Schaltbau changeover unit. For this purpose, the electrical loads are being grouped in a way that ensures that they are always supplied with the nominal voltage they require, irrespective of the kinds of voltages used in the European railway systems (according to UIC550).

After the changeover the correct electrical configuration is being tested in advance of its functional release. In addition to that, an internal camp-on circuit prevents an unnecessary regrouping of the loads when a peak phase change occurs within the range of 1.5kV; this equals 25kV at 50Hz catenary voltage as supplied by the three-phase grid.

The new ZH1114 series voltage selector is designed for use with passenger coaches and for the electric configuration of inverters for auxiliary equipment in locomotives and multiple units. It is also suitable for freight cars with increased requirements for a supply of voltage, such as those that ensue from contemporary logistics calling for ever more comfort and remote monitoring possibilities to make the whole transport chain safer and more transparent.

The ZH1114 identifies all UIC550 compatible voltages (1 kV / 16Hz; 1.5 kV / 50 Hz; and 1.5kVDC, 3 kV DC and 3 kV / 50 Hz). The measurement range is 5,000VAC (16Hz to 50Hz) and 6,000VDC respectively; the temperature range -25°C up to +85°C.

Sealed to IP20, the device features reinforced insulation when used at 3kVDC (or the maximum 5kVDC). The standard control voltage for the change-over unit is 24V.

The device supports customised setting via PC, so that the same hardware can be used for different configurations. With its outward dimensions of 204mm x 183mm x 250mm (length x depth x height), the voltage selector is mounting-compatible to its ZH914 series forerunner.

The ZH1114 is EN 50155 type tested, including for insulation, EMC, shock and vibration.