SIST EN 2349-318:2009

Overview

EN 2349-318:2006 (CEN) defines a standardized method to test the pick-up voltage at high temperature and drop-out (release) voltage at low temperature for relays and contactors used in aerospace applications. This Part 318 is intended to be used together with EN 2349-100 (general requirements) and forms part of the EN 2349 aerospace series. The procedure ensures components meet the electrical actuation characteristics required under extreme thermal conditions.

Key Topics

• Scope: Specifies how to measure pick-up and drop-out voltages under elevated and reduced temperatures respectively; applies to relays and contactors when used with EN 2349-100.
• Mounting method: Devices are wired per EN 2349-100 and placed in a heating or cooling cabinet with the coil connected through a switch to the power source.
• Pick-up voltage at high temperature:
  • Cabinet temperature is brought to the level specified in the product standard and stabilized.
  • Device is stored at that temperature for 1 hour before measurement.
  • Measurements are taken in all three perpendicularly opposed planes.
  • Two conditions defined: previously de-energized coil (stored 1 h, contacts unloaded) and previously energized coil (stored 1 h at rated voltage with coil energized, contacts unloaded).
  • Samples shall be returned to (23 ± 3) °C for at least 1 hour before further tests.
• Drop-out voltage at low temperature:
  • Cabinet temperature is set to the product-standard value and stabilized.
  • Device is stored at that temperature for 48 hours with the coil de-energized and contacts unloaded.
  • Release voltage and contact voltage drop are measured in all three orthogonal planes while maintaining the low temperature.
  • To limit self-heating, the coil may be energized for no longer than 30 seconds during measurement.
• Test criteria: Measured values must fall within limits specified in the applicable product standard.
• Verification tests: Additional verification per EN 2349-201, EN 2349-301, EN 2349-303, EN 2349-307 and EN 2349-412 as applicable.

Applications

This standard is essential for:

• Design validation - proving relay and contactor actuation across temperature extremes.
• Qualification and acceptance testing - aerospace manufacturers and suppliers can demonstrate compliance.
• Procurement and quality control - used in specifications for part acceptance and lot testing.
• Maintenance and troubleshooting - establishing baseline actuation voltages for field inspections.

By following EN 2349-318:2006, organizations ensure reliable electrical switching performance in thermal extremes, reducing risk in critical aerospace systems.

Related Standards

• EN 2349-100 - General requirements for relays and contactors
• EN 2349-201 - Visual inspection
• EN 2349-301 - Pick-up and drop-out voltage (general)
• EN 2349-303 - Dielectric strength
• EN 2349-307 - (referenced verification tests)
• EN 2349-412 - Seal

This Part 318 is published under the CEN/ASD-STAN framework and should be used in conjunction with the product-specific EN 2349 requirements.