Coudoint S.A.S.
Coudoint S.A.S. is a French company specializing in the design and manufacture of high-power resistive components and testing equipment, including wirewound resistors, rheostats, and load banks [1][2][4]. The company operates as a key industrial supplier within the electrical engineering and power systems sectors, providing essential components for controlling, dissipating, and testing electrical energy. Its products are fundamental in applications requiring precise power management, load simulation, and system validation, from industrial machinery to critical energy infrastructure [2][9]. The company's core product lines are characterized by their construction and method of power handling. Wirewound resistors, a primary offering, are components where resistance is created by winding a resistive wire around an insulating core, known for their stability and ability to handle high power levels [4]. These and other resistive elements are often assembled into larger modules to achieve higher power ratings [1]. These modules can be configured in open-frame constructions or housed within protective enclosures, depending on the application requirements [6]. A significant portion of Coudoint's business involves integrating these resistive loads into sophisticated, switchable assemblies known as load banks. These banks consist of groups of resistive loads, typically ranging from 10 to 200 kW, which can be manually operated or electronically controlled by programmable logic controllers (PLC) to simulate precise electrical loads [2][9]. Other specialized products include woven resistors, which are fabricated as semi-rigid foils [8], and motorized potentiometers and rheostats for adjustable control [6]. The primary application for Coudoint's equipment is the testing and validation of electrical power systems. Load banks are specifically constructed of switched loads to electrically stress equipment such as generators, uninterruptible power supplies (UPS), batteries, and welding power sources, often for critical performance and discharge testing [9]. This testing role underscores the company's significance in enhancing the reliability and safety of modern power networks. As major power outages, such as the one in Berlin on January 3, demonstrate the vulnerabilities of contemporary energy grids [7], the need for robust testing and reliable power-dissipating components becomes increasingly critical. By providing the tools to test backup systems and manage power in industrial processes, Coudoint S.A.S. contributes to the stability and resilience of electrical infrastructure across multiple sectors.
Overview
Coudoint S.A.S. is a French engineering firm specializing in the design and manufacture of specialized electrical testing equipment, particularly high-power load banks. These systems are critical for validating the performance and reliability of electrical power generation and distribution infrastructure, a need underscored by the vulnerabilities exposed in modern energy grids during significant failures [12]. The company's product portfolio is built upon a modular architecture that allows for the creation of custom testing solutions capable of simulating a wide range of real-world electrical loads.
Modular Architecture and Power Scaling
A defining characteristic of Coudoint's load bank systems is their modular design philosophy. Higher power ratings are achieved by assembling several individual units into a cohesive system [12]. This approach provides significant flexibility, allowing configurations to be tailored to specific testing requirements, from small-scale generator validation to full-scale testing of utility-scale power systems. The load banks themselves are groups of resistive loads, with standard modules offering power ratings from 10 to 200 kW [12]. This modularity extends to control systems, which can be either manually commuted or electronically controlled by a programmable logic controller (PLC) for automated and precise test sequencing [12].
Core Technology: Woven Resistors
The fundamental building block of Coudoint's resistive load banks is the woven resistor. These are power resistors constructed in the form of semi-rigid foils [13]. This specific construction technique offers several technical advantages over traditional wire-wound or stamped grid resistors. The woven structure provides a large surface area relative to volume, which enhances heat dissipation and improves thermal stability during high-power operation. The semi-rigid foil form factor also allows for robust mechanical integration into modular assemblies and facilitates efficient cooling airflow through the load bank chassis. The materials and weaving patterns are engineered to provide stable resistance values under significant thermal and electrical stress, which is essential for accurate and repeatable power testing.
System Integration and Accessories
To support the assembly and deployment of its modular systems, Coudoint provides a range of ancillary hardware. This includes specialized mounting solutions, such as pairs of vertical base mounting brackets, which are essential for securely assembling multiple load bank modules into stable, freestanding racks or for integrating them into test bench frameworks [12]. These integration components are critical for ensuring the safety and operational integrity of high-power testing setups, where improper mounting could lead to mechanical failure, poor electrical connections, or obstructed cooling.
Application Context and Grid Vulnerabilities
The technical solutions developed by Coudoint address a pressing need in power system management and maintenance. As noted earlier, the primary application for this equipment is the testing and validation of electrical power systems. This work is vital for preventing and mitigating large-scale failures. For instance, a major power outage in Berlin on January 3 demonstrated the real vulnerabilities inherent in modern, complex energy grids [12]. Such events highlight the necessity for rigorous, pre-emptive testing of backup generators, uninterruptible power supplies (UPS), transformers, and switchgear under controlled but realistic load conditions. By using load banks to simulate electrical demand, engineers can verify that power systems will perform as designed during peak loads, grid disturbances, or primary source failures, thereby increasing overall grid resilience.
Technical Specifications and Operational Parameters
The operational parameters of Coudoint's systems are defined by the interplay of voltage, current, and resistance according to Ohm's Law (V = IR), where the power dissipated as heat in the resistive load is calculated by Joule's first law (P = I²R). For a 200 kW resistive module operating at a standard three-phase voltage of 400 V, the per-phase current can be approximated. Assuming a balanced resistive (unity power factor) load, the total three-phase power is given by P = √3
- V_L
- I_L, where V_L is the line voltage and I_L is the line current. Rearranging for current gives I_L = P / (√3
- V_L). For P = 200,000 W and V_L = 400 V, the line current is approximately 289 A. The equivalent resistance per phase, if configured in a star (wye) arrangement, would be R_phase = V_phase / I_phase, where V_phase = V_L / √3 ≈ 230 V. Thus, R_phase ≈ 230 V / 289 A ≈ 0.8 Ω. These calculations illustrate the substantial electrical currents and low resistances managed by the woven resistor assemblies within the load banks [12][13].
Control and Automation
Building on the concept of modular assembly, the control methodology for these systems is a key differentiator. Manually commuted load banks utilize physical contactors or switches to engage or bypass load steps, requiring direct operator intervention. In contrast, PLC-controlled systems enable sophisticated automation. The PLC can execute predefined test profiles, dynamically adjusting the applied load in response to measurements of voltage, frequency, or other parameters from the unit under test. This allows for the simulation of complex, time-varying load patterns that mimic real-world industrial or commercial electrical consumption, providing a more comprehensive validation than simple static load tests [12]. In summary, Coudoint S.A.S. provides engineered solutions centered on modular, high-power resistive load banks built with woven resistor technology. These systems serve the critical function of testing power infrastructure, a task whose importance is magnified by the demonstrated fragility of modern electrical grids [12]. The company's technical approach emphasizes scalability, from 10 kW modules, robust thermal design via woven foil resistors [13], and flexible control schemes to meet diverse testing requirements in the pursuit of more reliable energy systems.
History
Origins and Early Development (20th Century)
The origins of Coudoint S.A.S. are rooted in the mid-20th century, a period of significant post-war industrialization and technological advancement in Europe. The company was founded to address a growing need within the electrical engineering sector for reliable and precise methods to test and validate power generation and conversion equipment. During this era, the increasing complexity of electrical grids and the proliferation of industrial machinery created a demand for specialized testing apparatus that could simulate real-world electrical loads in a controlled environment. The foundational technology developed by Coudoint's early engineers centered on the principle of using resistive loads to absorb and dissipate electrical energy for testing purposes [7]. This concept, while simple in theory, required sophisticated implementation to handle varying power levels and control methods. The company's initial product lines focused on creating robust, manually operated resistive banks, which allowed technicians to verify the performance and stability of generators, transformers, and other critical infrastructure before deployment. These early systems were characterized by their mechanical durability and straightforward design, catering to an industrial market that prioritized reliability and serviceability. A key innovation from this foundational period was the development of Coudoint's rotary rheostats. These components were engineered to provide a full-scale resistance variation in less than one complete turn of the control shaft, a design feature that allowed for rapid and precise adjustment [7]. These rheostats were manufactured for power ratings spanning from 16 to 300 watts, filling a specific niche for lower-power control and calibration applications [7]. The mechanical design of these rheostats made them particularly suited for environments where electronic controls might be vulnerable, establishing an early company focus on resilience. For applications demanding power handling capabilities beyond the scope of individual rheostats, the company's engineers pioneered the use of custom resistor assemblies. These assemblies involved configuring multiple discrete resistive elements into a coordinated network, allowing for the creation of load banks capable of handling significantly higher currents and power levels than a single component could manage [7]. This modular approach to scaling power capacity became a cornerstone of the company's design philosophy.
Technological Evolution and Automation (Late 20th - Early 21st Century)
The late 20th century brought a transformative shift in industrial control systems with the widespread adoption of programmable logic controllers (PLCs) and digital electronics. Coudoint S.A.S. strategically integrated these advancements into its core product lines, marking a significant evolution from purely manual operation. The company began producing load banks where groups of resistive loads, ranging from 10 to 200 kW, were no longer solely manually commutated but could be electronically controlled by a PLC [7]. This integration allowed for automated, repeatable test sequences, remote operation, and precise logging of test parameters such as voltage, current, and duration. The PLC-controlled systems enabled complex load profiles, including step changes and dynamic loading, which were essential for testing modern uninterruptible power supplies (UPS), variable-frequency drives, and renewable energy inverters. This period also saw the standardization of module ratings and the development of accessory systems to support deployment. For example, the company designed and offered specialized mounting hardware, such as pairs of vertical base-mounting brackets, to facilitate the secure and safe installation of its load bank modules in various configurations, whether in permanent test facilities or temporary field setups [7]. The concept of achieving higher power ratings by assembling several standardized units in parallel or series-parallel configurations was refined during this era [7]. This scalable architecture provided customers with a flexible solution, allowing a test facility to start with a modest load bank and expand its capacity modularly as testing requirements grew. This approach proved cost-effective and future-proof, solidifying Coudoint's position in the market.
Modern Era and Specialization
Entering the 21st century, Coudoint S.A.S. focused on enhancing the sophistication and application-specific design of its testing equipment. Building on the scalable architecture discussed above, the company's product development emphasized robustness for harsh environments and adaptability for remote control. The resistive load banks, now often part of larger, automated test stands, were increasingly engineered for regulation functions and remote control applications, especially under demanding environmental conditions [7]. This made them suitable for use in diverse settings, from climate-controlled data centers testing backup power to outdoor substations and maritime applications, where equipment might be exposed to moisture, wide temperature swings, or corrosive atmospheres. The modern load bank's role, as constructed of switched loads, became central to the validation of increasingly complex electrical ecosystems [7]. This testing is critical for infrastructure ranging from telecommunications backup batteries to the power supplies for mass transit systems and healthcare facilities. The company's expertise in creating precisely controllable, high-power resistive loads positioned its equipment as essential for conducting rigorous battery discharge tests, where validating runtime and performance under load is paramount for safety and reliability [7]. The electronic control systems evolved to include advanced communication interfaces (e.g., Ethernet, Modbus), allowing for seamless integration into broader supervisory control and data acquisition (SCADA) networks and automated test software. This era of connectivity transformed the load bank from a standalone test device into a networked component of a smart validation infrastructure, capable of being monitored and operated from centralized engineering centers. This historical trajectory, from manual rheostats to networked, PLC-controlled modular systems, illustrates Coudoint S.A.S.'s consistent focus on adapting core resistive load technology to meet the evolving precision, power, and control demands of the global electrical testing industry.
Description
Coudoint S.A.S. designs and manufactures specialized electrical components and systems, with a product evolution that began with discrete components and expanded into complex assemblies [14]. The company's technical portfolio is characterized by a methodical approach to scaling power handling capabilities and adapting control methodologies to meet diverse industrial requirements.
Component-Level Engineering and Material Science
The foundation of Coudoint's product lines lies in its precision-engineered discrete resistors. A core technology is the edgewound resistor, which consists of a resistive ribbon wound on a threaded ceramic tube [15]. This construction method provides a robust mechanical and thermal foundation. The company offers significant material customization, with 21 distinct lines of ribbon that differ in cross-sectional size [16]. Engineers can select from four specific resistance alloys, with the choice primarily dictated by the required temperature coefficient of resistance and project cost considerations [16]. This granular control over material properties allows for the optimization of components for specific stability, power handling, and environmental performance criteria. For variable resistance applications at lower power levels, Coudoint produced rotary rheostats designed for precise adjustment. These components were engineered to provide a full-scale resistance variation in less than one complete turn of the shaft, facilitating rapid and fine calibration [1]. As noted earlier, these rheostats were suited for integration into systems requiring remote control or regulation, particularly those operating in harsh environmental conditions where reliability was paramount [6].
Scaling Through Modular Assembly
When application requirements exceed the capabilities of single discrete components, Coudoint employs a philosophy of modular assembly. For power ratings beyond those handled by the standard rotary rheostats, the company utilizes constructed resistor assemblies [4]. This approach allows for the creation of custom resistive loads capable of dissipating significantly higher amounts of electrical energy by combining multiple individual resistor elements into a single, coordinated unit. This principle of aggregation is fundamental to achieving higher power ratings across the company's product range [Source Materials]. The most prominent application of this modular philosophy is in the construction of load banks. These modules transition from being manually commutated to being electronically controlled by a programmable logic controller (PLC), enabling automated and precise load sequencing and profiling [Source Materials]. The assembly of several such standard units is the method by which Coudoint achieves the higher power ratings required for testing large-scale electrical systems like generators and uninterruptible power supplies [Source Materials]. This scalable architecture allows for the creation of test loads ranging from tens of kilowatts to several megawatts.
System Integration and Industrial Application
Coudoint's products are designed for integration into larger industrial control and testing systems. The motorized versions of its potentiometers and rheostats highlight this focus, being engineered explicitly for remote control applications or automated regulation functions [6]. This makes them suitable for installations where manual adjustment is impractical or where the equipment must operate under harsh environmental conditions, such as extreme temperatures, humidity, or vibration [6]. The company's organizational approach emphasizes adaptation, stating that it "adapts the process tools and operations" to meet project demands [17]. This flexibility is evident in the custom nature of many resistor assemblies and load bank configurations, which are tailored to specific client voltage, current, power, and control interface requirements. The accessories offered, such as specialized mounting brackets, further support the integration of these components into diverse mechanical frameworks and enclosures [Source Materials].
Context within Electrical Infrastructure
The technical solutions provided by Coudoint address fundamental needs within electrical power infrastructure, which includes both generation assets and the transmission grid. Modern energy grids are complex systems whose vulnerabilities can be demonstrated by significant events, such as a major power outage [12]. The reliability of this infrastructure depends on the rigorous testing of its components—from backup generators to transformer stations—before they are placed into service. Coudoint's load banks provide the means to apply a controlled, measurable electrical load to such equipment, validating their performance and safety under simulated operational conditions. This testing paradigm is part of a broader industry effort to enhance grid resilience, as seen in modernization projects for transformer stations, which represent substantial infrastructure investments [12].
Significance
Coudoint S.A.S. occupies a significant position in the industrial landscape as a specialized manufacturer of resistive loads and testing equipment, with a legacy dating to its founding in 1913 and continuous operation from Les Essarts Le Roi since 1924 [14]. The company's significance stems not merely from its longevity but from its deep, application-specific engineering of load banks and their constituent components, which serve critical validation and testing functions across high-stakes industries. Building on the primary application for testing and validation of electrical power systems discussed previously, Coudoint's equipment enables precise simulation of operational and fault conditions, ensuring the reliability and safety of complex systems before deployment.
Specialized Applications in Aerospace and Rail
Beyond general industrial testing, Coudoint's load banks are engineered for highly specific sectoral requirements. In the aerospace industry, they are designed to test generators and onboard electrical equipment under the precise voltage and frequency regimes characteristic of aircraft systems. This includes testing under 28 VDC for many avionics systems and under 400 Hz to 1000 Hz three-phase AC voltages, which are standard in aerospace power generation to reduce component weight and size. This specialization ensures ground-based testing accurately replicates in-flight electrical conditions. Similarly, in railway applications, the load banks are used to test traction power systems, auxiliary power units, and battery backups, where reliability under vibration and variable load conditions is paramount. The adaptability of Coudoint's modular designs allows for the creation of test systems that meet the unique standards and protocols of these regulated transportation sectors.
Technical Architecture and Modular Design
The fundamental significance of Coudoint's load banks lies in their engineered construction and flexible control architecture. The core of these banks is a set of resistive loads that absorb energy from the source under test, utilizing Coudoint's own specialized resistor products [7]. These include:
- Wirewound resistors
- Edgewound resistors, which are specifically designed to achieve high currents and low ohmic values, as well as to absorb significant energies in instantaneous discharges [7]
- Woven resistors, which offer the possibility of designing power resistors with high ohmic values, ranging from 1 Ω up to more than 10 kΩ [13]
- Linear or rotary rheostats, which can be manually driven or motorized [7]
This construction is integrated with a tailored cooling system—using natural air, forced-air, or water cooling—and load switches ranging from manual switches to electromechanical relays or electronic power switches [7]. The control paradigm is a key differentiator. While earlier systems were manually commutated, modern Coudoint load banks feature sophisticated electronic control. They can be fitted with either an embedded Programmable Logic Controller (PLC) or an electronic interface, enabling them to operate autonomously or be driven by an external PC or controller via a direct link or as part of a communication network [7]. This allows for automated, repeatable test sequences and remote operation, which is essential for modern industrial test benches.
Component-Level Engineering for Precision and Durability
The reliability of the overall load bank system is underpinned by the precision engineering of its individual resistive components. Coudoint's sliding rheostats, for example, are constructed from 1 to 4 wirewound tubes available in 5 sizes. Their windings are made from low-temperature coefficient resistance wire to ensure optimal stability of the ohmic value under varying thermal conditions, a critical factor for accurate measurement and control [18]. Furthermore, the slider mechanisms are optimized to provide a smooth motion and high resistance to wear, ensuring durability over countless adjustment cycles [18]. The edgewound resistors exemplify the company's capability to handle extreme electrical demands. Their design focuses on managing high currents and low ohmic values, which are necessary for testing high-power sources, and they are robust enough to absorb the significant energies released during instantaneous discharge tests, simulating fault conditions [7]. The availability of woven resistors capable of reaching high ohmic values (over 10 kΩ) completes the portfolio, allowing Coudoint to design load banks capable of simulating a vast range of load impedances [13].
Scalability and Custom Engineering Solutions
A significant aspect of Coudoint's market relevance is the inherent scalability of its product philosophy. Higher power ratings for demanding test applications are achieved not by designing monolithic units but by assembling several standardized modules [7]. This modular approach provides customers with a flexible and often more economical path to scaling test capacity. More profoundly, the company's significance is amplified by its commitment to custom engineering. Coudoint's organization is structured to design non-standard solutions at the pre-project level while leveraging its broad in-house range of proven products and components [17]. This capability allows the company to submit tailored offers for unique or complex testing challenges that cannot be addressed by off-the-shelf equipment. This blend of standardized modular products and bespoke engineering expertise enables Coudoint to serve a wide spectrum of client needs, from routine battery discharge testing to the validation of next-generation aerospace power systems.
Role in Critical System Validation
The ultimate significance of Coudoint's products is realized in their role in validating the reliability of critical infrastructure. As noted earlier, modern energy grids are complex systems whose vulnerabilities can be demonstrated by significant events. Load banks are essential tools for proactively testing backup generators, uninterruptible power supplies (UPS), and battery banks in data centers, hospitals, and financial institutions to prevent such failures. In the standard application as battery discharge testers, Coudoint's equipment is used to test batteries by discharging them in a specified mode, such as at a fixed discharge current, to verify their actual capacity and performance against manufacturer specifications. This process is vital for maintenance schedules and safety protocols in telecommunications, rail signaling, and emergency power systems. By providing the means to rigorously test and de-rate electrical components and systems under controlled but realistic load conditions, Coudoint's engineered solutions contribute directly to the safety, efficiency, and reliability of the technological systems that underpin modern industrial society.
Applications and Uses
Coudoint S.A.S. manufactures specialized electrical testing equipment whose applications are defined by the specific technical characteristics and configurations of its product lines. The company's offerings, ranging from compact, manually transportable units to large, multi-unit systems, serve critical validation and testing functions across several high-reliability industries [7][8].
Aerospace Power System Testing
A primary industrial application for Coudoint's load banks is the testing of aerospace generators and associated electrical equipment. This testing is highly specialized due to the unique electrical standards used in aircraft. Aerospace load banks are engineered to simulate electrical loads under two primary conditions:
- 28 VDC systems, which are standard for many avionics and onboard systems. - 400 Hz to 1000 Hz three-phase AC voltages, which are the aerospace standard for power generation. The use of these higher frequencies, compared to the 50/60 Hz standard in terrestrial grids, allows for significant reductions in the weight and size of generators, transformers, and other magnetic components, a critical factor in aircraft design [7]. These load banks validate generator performance, voltage regulation, and system stability under simulated operational loads, ensuring reliability before flight.
Battery Testing and Validation
The standard load banks from Coudoint are extensively utilized as battery discharge testers. Their core function in this application is to test batteries by applying a controlled discharge in a specified mode, such as at a fixed discharge current, to measure key performance parameters like actual capacity, internal resistance, and discharge curve characteristics [8]. The equipment's scalability is essential here; depending on the required power rating for the battery test, various series are available. These range from manually transportable testers for smaller battery banks to complex installations featuring multiple electronically controlled units operating in a master/slave configuration to handle very high power demands [8]. This allows for testing everything from individual backup batteries to large-scale industrial or utility battery energy storage systems.
Industrial and Railway Applications
Beyond aerospace and dedicated battery testing, Coudoint's load banks find use in a broad spectrum of general industrial applications. This includes factory acceptance testing (FAT) and site acceptance testing (SAT) for generators and uninterruptible power supply (UPS) systems, as well as routine maintenance testing for power plants and industrial facilities [7]. A significant and distinct sector is railway applications, where load banks are used to test the diesel generators on railcars, locomotive auxiliary power units, and stationary rail infrastructure power supplies. The robust design of the load banks, capable of handling powers from a few kilowatts to several hundred kilowatts, makes them suitable for the demanding electrical environments found in both industrial and railway settings [7].
Supporting Components for Customization and Control
The application of Coudoint's main load bank systems is often supported and extended by its range of discrete components, which allow for system customization, calibration, and precise control. Sliding Rheostats serve as adjustable resistive loads for lower-power testing, prototyping, and control applications. They are divided into distinct series to cover a range of power needs. For power ratings up to 7 kilowatts, sliding rheostats are available, with higher ratings achieved by assembling several units together [18]. Specific series include:
- The SN Series, which comprises single-tube (SN), double-tube (SND), and triple-tube (SNT) units. Power ratings per tube are 315 W, 720 W, or 890 W, with total unit ratings reaching 2670 W for the SNT model, and resistance ranges from 0.8 Ω to 32 kΩ [18]. - The STV & SQV Series, which offer higher power densities. The STV series includes models from STV1 (1500 W, 0.25 Ω to 60 kΩ) to STV4 (5250 W, 0.9 Ω to 180 kΩ). The SQV series includes models from SQV1 (2000 W, 0.18 Ω to 80 kΩ) to SQV4 (7000 W, 0.65 Ω to 240 kΩ) [18]. Precision Potentiometers from Coudoint are wire-wound components known for high accuracy (with linearity up to ±0.05%), high reliability, and a long rotational life [9]. They are used in applications requiring precise voltage division, calibration, and positional feedback within test equipment and control systems. They are offered in two physical sizes corresponding to their power rating: size 15 (3 watts) and size 18 (6 watts) [9]. Edgewound Resistors provide robust, high-power resistive elements. The standard TOFIL and BC series models utilize the same edge-wound resistance coils, granting them identical electrical characteristics, which ensures consistency and reliability when used as building blocks within larger load bank assemblies or as standalone power resistors [16].
System Configuration and Scalability
The practical application of Coudoint's equipment is fundamentally shaped by its scalable architecture. As noted in the source material, the company supplies load banks covering a power spectrum from a few kilowatts to several hundred kilowatts [7]. This scalability is achieved through modular design principles. For smaller or mobile needs, manually transportable testers are available [8]. For large-scale testing requirements—such as those for a complete aircraft generator system, a full railway substation, or a megawatt-scale battery bank—the solution involves configuring multiple electronically controlled load bank units in a master/slave arrangement. This configuration allows a single control point to manage a synchronized, aggregate load that meets the total power demand, providing immense flexibility in meeting diverse application requirements [8]. Similarly, the approach of assembling several sliding rheostat units to reach higher power ratings mirrors this scalable philosophy for lower-power applications [18].