Modes of public transport such as high-speed trains, city transit systems and freight trains provide the ideal solution to meet the increased demand for more mobility whilst helping to fight pollution and traffic congestion.

Power electronics is essential for driving and controlling energy in these systems.

For both electric or diesel trains, traction is provided by electric motors driven by inverters that rely on J&D transducers to measure, optimize and adjust the power sent to the motors, improving performance and reliability.


J&D transducers provide control and protection signals to power converters and inverters that regulate energy both to the electric motors (for propulsion) and to the auxiliaries (for air-conditioning, heating, lighting, electrical doors, ventilators, etc).

Voltage networks vary from one country to another.

J&D transducers monitor them closely to ensure power electronics work accordingly.


Global systems for propulsion of mining trucks are similar to the ones used for diesel-electric railway locomotives.

Current and voltage transducers enable inverter control which is essential for the efficient propulsion of trucks.


The rail industry is constantly evolving.
Privatization of rail networks brought new requirements such as rail maintenance with the monitoring of points (switches) machines or signaling conditions.

J&D can help to meet these standards thanks to new families of transducers.
J&D provides the same control and protection signals for both on-board applications and wayside substations.

Main applications for Trackside:

To minimize train service interruptions due to equipment breakdown and to reduce lifecycle costs, it is key to do a preventive maintenance of crucial track equipment (points, crossing gates, signaling, rails…). Online monitoring helps to take the required preventive actions before abnormalities lead to failures.

For exemple, the current of the electric motor of a point machine can be measured by a transducerand monitored.

Any variation from the normal current waveform indicates an early warming of equipment failure that will require preventive maintenance.
A quick scheduled maintenance intervention will allow not to interrupt the rail traffic for a lot of costs saving.


As air pollution becomes more and more severe, governments in many countries have set goals to implement or convert transportation from fossil fuels to electricity.
The railway industry is also evolving into new technologies using electricity and complex & fast machines to ensure a sustainable environment for the present and the future.

J&D Current Transducers will play an even more important role in the electric train and electric motor markets.

1. Obtained Efficiency and Reliability by monitoring the current status

Traction is driven by inverters and electric motors. It provides control and protection signals to power converters and inverters that regulate energy to all electric motors and auxiliary equipment. In this case, the current transformer is considered an important role in ensuring that the inverter and electric motor operate continuously and reliably. This is because current pass through both transformers, circuit breakers, and train lines used for traction. Therefore, how you control the input current affects the reliability of the equipment.

J&D Current Transducers provides various range of inner diameter and high-insulated voltage sensor for maximize the efficiency of equipment by controlling the current passing through and delivering high-accuracy signals.

2. The need of Voltage Transducers

In the railway industry, voltage is related to cost and efficiency. Accurate and reliable measurements are required to maximize the energy efficiency provided by the voltage network.

Therefore, J&D proposes Voltage transducers that measure a wide range of voltages.


– Main converter for urban transportation systems(metros – trams – trolleybuses)

– Inverters, converters, rectifiers

– Auxiliary power units

– Circuit breaker, for transformers, DC link

– Energy metering

– Rolling stock heavy traction, diesel electric

– Mining trucks


What makes the Trackside run smoothly?

In order to facilitate railway traffic networks such as trains, railroad, track switches, control cabinets (supply power, etc…) and control rooms, the ability to continuously monitor and maintain track conditions is required.

In addition the railway industry is utilizing IoT technology to increase the efficiency of train operations by not only providing services to reduce congestion, but also enabling timely facility investment and maintenance.

In the advanced and complex IoT industry, it is also important to understand and control the electrical signals flow in to each device.

The Need for CT on Trackside & The Role of J&D CT

J&D Current Transducers detects the current flow and changes or abnormal current to determine the correct signal of the current so that the railway network equipment can operate smoothly and without problems. This enables continuous and reliable information transmission and sharing with each other within the railway network. Therefore, CT will play an important role in transmitting information in railroad networks by accurately grasping electrical signals.

This serves as a preventive diagnosis so that it can occur in railway operations such as incorrect information transmission to the control room or late changeover.


– Track objects monitoring
– Points machines
– Tracks circuits
– Crossing gates
– Substations(circuit breaker for transformers…)
– Control and Safety Systems