Power Frequency Magnetic Field-Testing Labs in Uusimaa

Power Frequency Magnetic Field Testing

Power frequency magnetic field testing evaluates how electronic equipment responds to magnetic fields generated by power systems operating at 50 Hz or 60 Hz. High currents flowing through power distribution conductors, transformers, and switchgear produce low-frequency magnetic fields that can couple into nearby electronic circuits through inductive coupling, inducing unwanted voltages or currents in sensitive signal paths.

The test is performed by placing the device under test (DUT) inside a calibrated magnetic field generated by single-axis induction coils or Helmholtz coil systems. These coils are driven by a controlled power frequency current source, producing a uniform sinusoidal magnetic field within the test volume. The magnetic field strength is monitored and calibrated using magnetic field probes to ensure the required field level is achieved at the DUT location.

Testing is typically conducted by applying the magnetic field sequentially along three orthogonal axes (X, Y, and Z) to evaluate susceptibility to magnetic coupling from different orientations. The DUT operates in normal functional modes while exposure levels are increased to specified field strengths, allowing engineers to observe any functional degradation, performance deviation, or loss of operation.

Power frequency magnetic field immunity testing is defined in IEC 61000-4-8, which specifies the coil configuration, calibration procedures, field uniformity requirements, and test severity levels. Standard test levels commonly range from 1 A/m to 100 A/m, with higher levels used for industrial or substation environments. These tests verify the immunity of equipment installed in environments with strong power frequency magnetic fields, such as industrial facilities, power plants, and electrical substations.

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