Overview
EN ISO 17657-5:2007 (ISO 17657-5:2005) defines a verification procedure for welding current meters and monitoring devices that use a current sensing coil for measuring welding current in resistance welding. The standard applies to alternating current (50 Hz or 60 Hz) and direct current and covers a current range from 0.5 kA to 25 kA. It was adopted by CEN and published as EN ISO 17657-5:2007.
Key topics and requirements
- Scope & applicability
- Verification of welding current measuring systems (meters and monitoring devices) used in resistance spot, projection and seam welding.
- Current range: 0.5 kA to 25 kA; AC 50/60 Hz or DC.
- Test set-up
- Use a resistance welding machine, a master welding current meter with master (Rogowski-type) coil and the test meter/coil to be verified.
- Coil positioning should follow ISO 17657-2 (recommended positions B, F, H).
- Master system requirements
- Master meter and coil must be calibrated against a reference system (per ISO 17657-4) at least once a year.
- Master system accuracy must be higher than the test system.
- Classification by accuracy: Highly accurate ±1.0%, Accurate ±2.0%, Ordinary ±5.0% (ordinary class not used for checking).
- Environmental & operating conditions
- Operable at +5 °C to +40 °C, up to 95% relative humidity, altitudes up to 1 000 m, and in typical welding atmospheres (dust, oil mist, spatters).
- Test procedure & acceptance
- Verification in short-circuit condition, at three current levels (including near full-scale and medium), application time >0.1 s.
- Deviations are calculated as percent of the test meter’s full scale at the set range. If deviation exceeds required accuracy, the test meter/coil must be adjusted or repaired.
- Documentation & reporting
- Test report items specified (model/type of master and test meters and coils, ranges, positions, power type/frequency, readouts, deviations, weld times, environmental data, test date and signatures).
Applications - who uses this standard
- Welding engineers and quality managers implementing process control and traceability for resistance welding.
- Calibration laboratories, testing bodies and inspection agencies verifying welding current meters and sensors.
- Manufacturers of welding current meters, current sensing coils (Rogowski-type), and welding equipment.
- Maintenance and production technicians responsible for monitoring welding process consistency and product quality.
Related standards
- ISO 17657 series: Part 1 (Guidelines), Part 2 (Welding current meter with current sensing coil), Part 3 (Current sensing coil), Part 4 (Calibration system).
- ISO 669 (Resistance welding equipment - mechanical and electrical requirements).
Keywords: EN ISO 17657-5:2007, resistance welding, welding current measurement, verification, current sensing coil, Rogowski-type coil, welding current meter, calibration, welding quality assurance.
