SIST EN 2591-226:2008

Overview

SIST EN 2591-226:2008 is a European standard developed by the Aerospace and Defence Industries Association of Europe (ASD-STAN) under CEN. It defines a specific test method for assessing the corona level of electrical and optical connectors used in aerospace applications. This standard provides test procedures aimed at detecting the presence of sustained corona discharge-an electrical discharge phenomenon that can degrade connector performance and reliability-on mated pairs of connectors. SIST EN 2591-226:2008 is intended for use alongside the general test methods standard EN 2591-100 to ensure comprehensive testing of aerospace connector elements.

Key Topics

• Test Method for Corona Discharge
  The standard specifies a test setup and procedure to detect corona discharge at a sensitivity threshold of five picocoulombs or less. By applying a gradually increasing 50 Hz voltage to a mated connector assembly under reduced pressure, the test identifies the voltage level at which corona discharge occurs, known as the corona level.

• Test Circuit Configuration
  A detailed schematic setup is provided, including components such as a corona-free coupling capacitor, detector amplifier, input line filters, variable and high voltage transformers, and a discharge display. This ensures accurate and sensitive detection of corona discharge events.

• Specimen Preparation
  Connectors are tested in circuits using coaxial cables consistent with aerospace product standards and EN 4604-002. The connectors must be free from grease or similar compounds, and the sample should be purged of air prior to testing to maintain test accuracy.

• Corona-Free Apparatus
  Components of the test circuit must exhibit no corona discharge above the five picocoulombs threshold to avoid interference with the test results.

• Requirement Compliance
  The measured corona level for a connector must remain below limits prescribed in the relevant product standard, ensuring operational safety and reliability in aerospace environments.

Applications

SIST EN 2591-226:2008 serves a critical role in aerospace industry quality assurance and connector performance validation. Its applications include:

• Aerospace Electrical and Optical Connectors
  Verifying that connectors used in aircraft and spacecraft maintain reliable electrical and optical connections without corona discharge risks that could compromise system integrity.

• Connector Design and Certification
  Providing manufacturers and testing laboratories with standardized procedures to certify products meet aerospace industry corona discharge tolerances, ensuring compliance with safety and performance requirements.

• Maintenance and Quality Control
  Enabling post-production inspection and validation of connector assemblies to detect early-stage corona-related degradation that could lead to failures in the field.

• Research and Development
  Supporting R&D efforts aimed at improving connector designs to reduce corona discharge susceptibility under operational voltages and environmental conditions.

Related Standards

• EN 2591-100 - Aerospace series - Elements of electrical and optical connection - Test methods - Part 100: General
  This standard must be used in conjunction with SIST EN 2591-226:2008 as it provides overarching general test procedures applicable to aerospace connector elements.

• EN 4604-002 - Aerospace series - Cable, electrical, for signal transmission - Part 002: General
  Defines requirements for the coaxial cables and electrical wiring used in the corona discharge test circuit.

• Additional Aerospace Connector Standards
  Various standards within the EN 2591 series provide complementary test methods covering mechanical, environmental, and electrical properties crucial to connector certification.

Summary

SIST EN 2591-226:2008 provides a vital testing protocol focused on identifying and limiting corona discharge in aerospace connector assemblies. By implementing this standard, aerospace manufacturers and testing facilities ensure the electrical and optical connectors meet stringent performance and safety criteria essential for high-reliability aerospace systems. This contributes directly to longevity, safety, and mission success in demanding aerospace environments.