The transducers of Witt enable a very accurate measurement of driving voltages and currents electrically insulated.
The transducers are used in DC-powered vehicles as well as in stationary facilities. The voltage that falls off an external shunt is transmitted potential-free. Thus, it is possible to measure on the “hot” side of the traction power supply.
This way it is possible to measure the available voltage in the railway engine after the pantograph. The TD 200 can also measure the voltage delivered by a substation.
The entire electronic is placed in a fully isolated plastic housing. The 4- 20 mA outlet is wired in a way that in case of a fault 0 mA will flow and such the following stages can detect an error.
The voltage to be measured is splitted in voltage divider (part of the device), limited (transient protection) and filtered. In the subsequent stage this voltage is converted into a high proportional frequency (60-800 kHz) and transferred by a optic fibre cable which is completely galvanically isolated. A subsequent frequency/voltage converter generates a proportional voltage that will – after a filtering in a final stage – be converted into electricity.
The necessary auxiliary voltage is provided in two separate transducers of the primary and the secondary side.
For further information please download the datasheet: