What are three key performance needs for HVAC/harsh environment connectors?
Connectors are complex assemblies whose performance is based on interactions of materials with electrical, mechanical, and environmental factors. Extensive testing is required to ensure proper performance and numerous industry standards have been developed for that purpose.Get more news about Harsh Environment Connector,you can vist our website!
This FAQ reviews 13 tests across three key performance indicators for connectors including electrical, mechanical, and environmental considerations for connectors used in heating ventilation, air conditioning (HVAC) systems, and other harsh environments. Some aspects of materials testing for connectors are discussed in the FAQ on “What’s the difference between needle flame and glow wire testing?”
Testing is the cornerstone for quantifying the performance of connectors in challenging environments. Three key areas are:
Electrical tests: the impact of high current and temperature rise poses challenges to components. Testing should evaluate wet insulation resistance, current carrying, impulse withstand, contact resistance, and other factors.
Mechanical tests: flexion testing, conductor pullout, cold impact, protection against contact, and low-level contact resistance are several of the basic mechanical considerations.
Environment tests: degree of protection, vibration, humidity, corrosion, and temperature shock, including highly accelerated life test (HALT) and highly accelerated stress screen (HASS) testing.
Whether testing is performed in-house or at an independent laboratory, the requirements of ISO/IEC 17025, General requirements for the competence of testing and calibration laboratories, should be met. Accreditation is mandatory for testing performed as part of regulatory compliance. The need for accreditation applies to all types of tests including electrical, mechanical, environmental, and so on.
Contact resistance is a basic connector performance specification. Bulk resistivity, or intrinsic resistance, describes the resistance of a material of a given size and area. Contact resistance, on the other hand, describes the resistance experienced when two conductors come into contact (Figure 1). IEC-60352-5 requires that contact resistance testing should be carried out using the millivolt level method specified by IEC 60512-2-1. Contact resistance is a complex phenomenon and is affected by constriction, film resistance, and stress relaxation. Constriction describes the narrowing of the true contact surface when two materials meet. Film resistance is the resistance created by unwanted resistive material (film) on the surface of the contact. Contact deformation can occur over time changing the shape of the contact as a result of stress relaxation.
Current carrying capacity should be measured in accordance with IEC 60512‑5‑2. Current carrying capacity is limited by the insulating parts of the connector housing and the thermal properties of the contact materials. It is dependent on the ambient temperature and self-heating of the contacts. The tests quantify carrying capacity versus ambient temperature.