Examination of the impact of design of a residual current protective device on the release frequency range

In the paper the results of experimental research on residual current protective devices with different design of the release system are presented. The application of a summing transformer and a power adjustment system in the secondary circuit affects the release frequency range. In the circuits of installations, where due to the specific features of the supplied devices, there are some current deformations from the sine waveform as well as frequencies different from the mains frequency (50 Hz), the commonly available residual current protective devices may not ensure the required level of shock protection.