The transducer TD1A01 from Witt Solutions GmbH enables very precise measurement of control voltages and electrically isolated currents.
The transducer is used in DC-powered vehicles as well as in stationary facilities. The voltage that drops at an auxiliary connection (shunt) is transmitted potential-free. This makes it possible to measure the “hot” side of the traction power supply. This also makes it possible to determine the available voltage in the railway motor downstream of the pantograph. The WITT TD1A01 can also measure the voltage produced by a substation.
The electronics are surrounded by a fully plastic cover. The 4 – 20 mA output is wired in such a way that 0 mA flows in the event of an error, which the following stations will detect as an error.
The voltage drop generated by the auxiliary connection is limited (temporary protection) and filtered. In the following stage, this voltage is converted into a highly proportional frequency (60 – 800 kHz) and transmitted through glass fiber, which is completely galvanically isolated. A subsequent frequency / voltage converter generates a proportional voltage, which – after a final filtering – is converted into electricity. The required auxiliary voltage is provided by two separate converters, a primary and a secondary side.
Technical data of the WITT TD1A01
| operating voltage
| 24 V DC
20 -70 ° C
| 0 – 60 mV is proportional to 4 – 20 mA
up to 1 kHz (-3dB) +/- 1% of the final value
| Protection against contact
Entrance to exit
Input to the auxiliary voltage
Output to auxiliary voltage
| 12 kV