Waveform Verification for IEC 61000-4-4 Electrical Fast Transients

Waveform From The EFT Generator

The test generator output shall be connected to a 50 Ω and 1 000 Ω coaxial termination respectively and the voltage monitored with an oscilloscope. The –3 dB bandwidth of the oscilloscope shall be at least 400 MHz. The test load impedance at 1 000 Ω is likely to become a complex network. The characteristics of the test load impedance are: – (50 ± 1) Ω; – (1 000 ± 20) Ω; the resistance measurement is made at d.c. The tolerance of the insertion loss of both test loads shall not exceed as follows: • ±1 dB up to 100 MHz • ±3 dB from 100 MHz up to 400 MHz.

Waveform From The Coupling Network

The waveform shall be calibrated in common mode coupling, this means to couple the transients to all lines simultaneously. The waveform shall be individually calibrated for each coupling line at each output terminal (L1, L2, L3, N and PE) of the coupling/decoupling network with a single 50 Ω termination to reference ground. The calibration is performed with the generator output at a set voltage of 4 kV. The generator is connected to the input of the coupling/decoupling network. Each individual output of the CDN (normally connected to the EUT) is terminated in sequence with a 50 Ω load while the other outputs are open. The peak voltage and waveform are recorded for each polarity.

Waveform From The Capacitive Coupling Clamp

A transducer plate shall be inserted into the coupling clamp and a connecting adapter with a low inductance bond to ground shall be used for connection to the measurement terminator/attenuator. The waveform shall be calibrated with a single 50 Ω termination at 2kV. The peak voltage and waveform parameters are recorded at the transducer plate output located at the opposite end of the clamp.