Pantograph Current Measurement via Resistive Section
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Solution Overview
Problem
Conventional current and voltage measuring devices for railway traction chains are bulky, heavy, and expensive, and their multi-voltage capabilities are complex and require structural modifications, posing challenges in efficiency and cost-effectiveness.
Innovation Solution
A current measuring device with an articulated structure that determines potential differences using operational amplifiers and resistive sections, integrated with a temperature probe and isolation transformer, and a voltage divider connected via an insulator foot, allowing for simplified wiring and reduced size, mass, and cost, while providing energy consumption measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional current measuring devices (current transformer, shunt, Hall effect probe) are used for multi-voltage traction chains, then current measurement capability is provided, but the device becomes bulky, heavy, and expensive
Solution Approach 1:
The patent extracts the current measurement function from conventional bulky devices (current transformers, shunts, Hall effect probes) and implements it using a simplified voltage measurement approach across a known resistive section of the pantograph. This extraction eliminates the need for heavy isolation components while maintaining measurement capability through the relationship I = V/R, where the resistance R is known from the pantograph's structural properties.
Solution Approach 2:
The patent makes the pantograph structure itself serve multiple functions: it remains the mechanical current collection structure while simultaneously acting as the resistive sensing element for current measurement. The same pantograph structure that collects current from the catenary also provides the resistive section through which voltage is measured to determine current, eliminating the need for separate dedicated measurement components.
2Measurement precision
If conventional voltage measuring devices (transformer with resistive bridge) are used for multi-voltage traction chains, then voltage measurement capability is provided, but the device becomes heavy and expensive
Solution Approach 1:
The patent extracts the voltage measurement function from conventional heavy devices (transformers with resistive bridges) and implements it using a simplified approach that measures voltage across a known resistive section of the pantograph. This extraction eliminates the need for heavy transformer components while maintaining voltage measurement capability through direct voltage sensing across the resistive element.
Solution Approach 2:
The patent makes the pantograph structure serve multiple functions: it remains the mechanical current collection structure while simultaneously providing the resistive section used for voltage measurement. The same structural elements that support current collection also serve as the sensing element, eliminating the need for separate dedicated voltage measurement components.
3Reliability
If optical fiber is used for wiring in voltage measuring devices, then isolation is provided, but the wiring becomes complex and structural modifications are required
Solution Approach 1:
The patent extracts the isolation function from complex optical fiber wiring systems and replaces it with electrical isolation achieved through high-voltage resistive dividers and isolated measurement circuits. This extraction eliminates the need for optical fibers and their associated routing complexity while maintaining electrical isolation through proven high-voltage engineering techniques.
Solution Approach 2:
The patent replaces the mechanical/optical isolation system (optical fibers) with an electrical isolation system based on high-voltage resistive dividers and isolated measurement circuits. This substitution uses electrical fields and high-voltage engineering principles instead of optical transmission, simplifying the wiring while maintaining isolation integrity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enables efficient, cost-effective current and voltage measurement in multi-voltage traction chains without the need for structural modifications, reducing size, mass, and complexity, while ensuring accurate energy consumption calculations.
Implementation Method 1
determining a potential difference between two points on the pantograph (1) to determine a current consumed by the traction chain
Implementation Method 2
a section (12b) of material with a known resistivity inserted into the structure of one of the arms (4, 3) of the pantograph (1)
Implementation Method 3
an isolation transformer (29) integrated into a support leg (11) of the pantograph (1)
Implementation Method 4
a temperature probe arranged on the current sensing member, said probe being connected to the operational amplifier to vary its gain as a function of temperature
Implementation Method 5
The capture of the current on the catenary line is provided by a so-called pantograph device comprising an articulated structure fixed to the roof of a railway train
Data Source
Figure 1
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AI summary
The device (20) has a determining unit for determining potential difference between two ends of sections (12a), proportional to current flowing on the sections of a current collecting unit e.g. pantograph (1), where the determining unit is constituted by a band(13), cable (14) and an operational amplifier (21). A multi-voltage pull chain of a railway vehicle e.g. rail car, is equipped with the collecting unit, where the current circulates on the collecting unit from a catenary line. A current transformer is integrated on a support frame (8) of the collecting unit. An independent claim is also included for a method for measuring current consumed by a multi-voltage pull chain of a railway vehicle.