Overview
IEC 63522-28:2025 is an international standard developed by the International Electrotechnical Commission (IEC) focusing on the testing and measurement of electrical relays. This part of the IEC 63522 series specifies a standardized test method to evaluate the thermoelectric electromotive force (e.m.f.) generated by electrical relay contacts when exposed to elevated temperatures. The standard ensures that electrical relays-ranging from electromechanical and reed relays to solid-state relays and their combinations-meet strict performance criteria under conditions simulating transportation, storage, and operational use.
Thermoelectric electromotive force arises when different metals connected at junctions experience varying temperatures, causing a current flow due to thermal potential differences. This standard defines how to measure and limit such voltage generation to maintain relay reliability and safe operation.
Key Topics
- Thermoelectric e.m.f. Measurement: The document describes a precise procedure for measuring the voltage generated by relay contacts under thermal stress, reflecting real-life usage scenarios.
- Test Setup and Conditions: Relay contacts are soldered to bare copper wires, connected to measuring devices maintained at room temperature. Tests are conducted with the relay coil energized at rated voltage and at temperatures near its maximum operational range.
- Test Procedure Timing: The measurement is taken once thermal equilibrium is reached or after four hours of exposure at high temperature, whichever occurs first.
- Specification of Parameters: Test conditions to be specified include soldering methods and materials used, ambient temperature of the test chamber, and acceptable e.m.f. limits.
- Evaluation Criteria: The measured e.m.f. must not exceed predefined limits to ensure relay safety and performance.
- Reporting Requirements: Test reports must document soldering methods, test chamber temperature, e.m.f. limits, and measured values for reproducibility and traceability.
Applications
IEC 63522-28:2025 is essential for manufacturers, engineers, and quality assurance professionals involved in the design, production, and testing of electrical relays used in various fields such as:
- Industrial Automation: Ensuring reliable relay operation in control systems exposed to temperature variations.
- Power Systems: Verifying relay integrity in protective relaying where temperature-induced voltages could affect circuit performance.
- Transportation and Storage: Evaluating relay robustness against thermally induced electromotive forces during logistics operations.
- Consumer Electronics and Appliances: Guaranteeing the safety and functionality of relays in household and office equipment.
- Renewable Energy Systems: Testing relays employed in solar inverters and wind turbines subjected to fluctuating thermal loads.
By adhering to this standard, stakeholders can better predict relay behavior during thermal stresses, reduce failure rates, and maintain system reliability.
Related Standards
- IEC 63522-0 (General and Guidance): Provides general principles and guidance for tests and measurements related to electrical relays. IEC 63522-28 is designed to be used in conjunction with this overarching part.
- Additional Parts of IEC 63522 Series: Cover other specific testing methods for electrical relays, including mechanical endurance, electrical endurance, and insulation resistance tests, contributing to comprehensive relay evaluation.
- ISO/IEC Directives, Part 1 and Part 2: Define rules and procedures for the preparation of IEC standards, ensuring consistent and transparent documentation.
- Electropedia: The IEC’s authoritative online dictionary for electrotechnology terms, including definitions relevant to relay testing and thermoelectric effects.
Adoption of IEC 63522-28:2025 ensures standardized, reliable, and reproducible measurements of thermoelectric electromotive force in electrical relays, augmenting overall safety and performance in diverse electrotechnical applications.
Open preview (PDF)Electrical relays - Tests and measurement - Part 28: Thermoelectric electromotive force (e.m.f.)
