Tool measures current in rail traction apps

DI Series transducers measure the small voltages developed across low-resistance ohmic shunts in the primary power conductors feeding rail traction motors, spanning ranges of 30 to 200mVRMS.

Featuring LEM's patented insulating technology, the DI series has been designed to enable rail-traction designers to meet the provisional EN 50463 standard for on-board energy monitoring.

When used with a shunt Class 0.2 accuracy, the DI reaches the required Class 1R accuracy.

The DI can then be part of the measurement chain of any on-board energy meter, as a key element in the recording of energy consumed (or returned to the supply under regenerative braking), according to the standards set out in the provisional standard.

Coupled to a shunt used for current measurement, the DI provides the voltage insulation (withstanding 18.5kVRMS/50Hz/for 1min as insulation test voltage) that is essential due to the high voltages met in vehicles that are supplied with energy from networks up to 3,000V.

DIs can easily be added to any existing shunts already mounted into the application when insulated operation is necessary.

With a current consumption of 20-25mA (plus the output current) and a frequency bandwidth of 10kHz, LEM's DI shunt isolator is said to meet the demands of modern rail systems and fulfils all new EMC requirements.

Other key features include a high level of partial discharge extinction voltage, adherence to safety standards, high quality and long life, together with low weight and flexible mechanical and electrical output to adapt to customer needs.

LEM has designed and produced the DI transducer according to the requirements of the International Railway Industry (IRIS).

The materials utilised comply with the fire and smoke requirements, which are mandatory in railway applications.

The DI is CE marked and is supplied with a five-year warranty, as are all LEM railway transducers.