SIST EN 2349-305:2009

Overview

SIST EN 2349-305:2009 is a European aerospace standard developed by CEN that specifies precise requirements and test procedures for measuring the bounce time of relays and contactors. Bounce time refers to the brief interval during which relay or contactor contacts repeatedly open and close before settling into a stable state. Accurate measurement and control of this parameter are crucial in aerospace applications to ensure reliable electrical performance and safety.

This standard is intended to be used in conjunction with EN 2349-100, which covers general requirements for aerospace relays and contactors. SIST EN 2349-305:2009 serves as a complementary methodology detailing how to test bounce time consistently and rigorously.

Key Topics

• Scope
  Defines the application of the bounce time test method specifically for aerospace relays and contactors.

• Test Procedures

  • Bounce time measurement applies to both normally-open and normally-closed contacts.
  • Testing performed by switching the rated voltage on and off to capture contact behavior.
  • Bounce time includes initial and subsequent contact bounces as defined with schematic references (Figures 2 and 3).
  • Contact load during testing should range between 5 mA and 100 mA.
  • Open contact voltage limits: maximum 6 V d.c. for devices rated ≤ 25 A, maximum 28 V d.c. for devices rated above 25 A.
  • Qualification tests require five recorded measurements for accuracy and repeatability.
  • A typical test circuit is identified to standardize testing setups.

• Test Criteria
  Relays and contactors must not exceed specified bounce times given in the relevant product standard, ensuring performance consistency.

• Normative References
  EN 2349-305 must be applied alongside EN 2349-100, which contains the overarching general requirements.

Applications

Relays and contactors are critical components in aerospace electrical systems, performing functions such as signal switching, power distribution, and system protections. SIST EN 2349-305:2009 ensures that:

• Safety and Reliability
  Bounce time measurements help prevent unwanted electrical noise, contact wear, or malfunction that could jeopardize aircraft safety.

• Quality Control
  Manufacturers can use this standard to verify relay and contactor performance during production and qualification testing, enabling consistent product quality.

• Maintenance and Compliance
  Aerospace engineers and maintenance teams use bounce time criteria to assess and validate component health during service intervals.

• Design Optimization
  Engineering teams can optimize relay and contactor designs to meet bounce time limitations, improving system responsiveness and lifespan.

Related Standards

• EN 2349-100: Aerospace series - Requirements and test procedures for relays and contactors - Part 100: General requirements
  Provides the foundational requirements for aerospace relays and contactors on which Part 305 depends.

• Other parts of the EN 2349 series may address additional electrical characteristics and testing protocols relevant to aerospace electrical components.

Summary

SIST EN 2349-305:2009 standard establishes a consistent, repeatable procedure for measuring the bounce time of aerospace relays and contactors, a key parameter affecting device performance and system reliability. Together with EN 2349-100, it forms a critical framework for manufacturers and aerospace engineers dedicated to ensuring the highest standards in electrical equipment used in flight-critical environments.

Keywords: EN 2349-305, aerospace relays, contactors, bounce time, relay testing, contactor testing, aerospace electrical standards, CEN standards, relay bounce time measurement, aerospace component testing