Overview
EN ISO 5826:2014 - "Resistance welding equipment - Transformers - General specifications applicable to all transformers" is the CEN-endorsed version of ISO 5826:2014. It specifies general requirements for transformers used in resistance welding equipment (the transformer alone or as a transformer‑rectifier unit). The standard covers transformers of IEC 61140 protection class I or II and applies to a range of transformer types and operating frequencies used in resistance welding.
What the standard covers
- Transformer types: single‑phase for a.c. welding (typically 50/60 Hz); single‑phase with rectifier for d.c. welding (50/60 Hz); single‑phase inverter transformers with rectifier for d.c. welding (400 Hz to 2 kHz); and three‑phase transformers with rectifier for d.c. welding (50/60 Hz).
- General construction and additional equipment such as thermal protection and output current sensing coils.
- Physical environment and operating conditions, including ambient temperature, humidity, altitude, handling, transportation and cooling liquid temperature.
- Testing requirements: type tests and routine tests with defined test conditions.
- Electrical safety: insulation resistance, dielectric strength, calibration of sensing coils, and protection against electric shock in normal and fault conditions.
- Thermal rating: temperature rise limits, heating test conditions and measurement methods.
- Performance parameters: rated output voltage (a.c. and d.c. no‑load), no‑load input current, short‑circuit voltage and output current under load.
- Cooling liquid circuit, dynamic behaviour, rating plate content and required instruction manual information.
- Annexes include example rating plates, altitude/cooling corrections, concept notes and a type code example.
Key technical topics and requirements
- Safety and insulation: requirements to protect against direct and indirect contact, including insulation resistance and dielectric strength tests.
- Thermal management: mandatory thermal protection and temperature‑rise testing to define permissible operating limits.
- Performance testing: type and routine test procedures for verifying rated output, short‑circuit voltage and no‑load currents.
- Documentation: mandatory rating plate fields and comprehensive instruction manual content for safe installation and operation.
Applications and users
- Applies to manufacturers, designers and test laboratories of resistance welding transformers and transformer‑rectifier units.
- Useful to OEMs of welding machines, quality assurance and compliance teams, safety engineers, and procurement specialists specifying welding equipment.
- Relevant for industries using resistance welding: automotive, aerospace, heavy machinery, and electrical fabrication.
Related standards
- References IEC 61140 (protection classes) and aligns with ISO/TC 44 (Welding and allied processes) and CEN/TC 121. Users should consult these and any machine‑specific welding standards when applying EN ISO 5826:2014.
Keywords: EN ISO 5826:2014, resistance welding transformers, transformer specifications, transformer‑rectifier, dielectric strength, thermal protection, short‑circuit voltage, welding equipment standards.
