A differential current transformer permits the measurement of differential current in single-phase or three-phase supply cables or in individual lines. Both current-carrying conductors (outward conductor and return conductor) are led through the current opening of the current transformer. The current measurement is performed by comparing the two conductors.

Any difference is displayed at the output of the differential current transformer. The use of highly permeable materials permits a typical current deviation of 10 mA upwards. The wide opening allows the supply lines, with the exception of the earthing conductor, to be led through directly. High sensitivity to current enables measurement in several stages:

• stage 1: Notice of a malfunction
• stage 2: Alarm
• stage 3: Switching off

• Measurement from 25 to 400 Hz
• Nanocrystalline core
• Transformer for measuring of differential current
• High-quality UL listed insulating materials (e.g. UL94-V0)
• Safe electrically isolated primary and secondary circuits
• Robust housing designs (for horizontal/vertical mounting)
• Variable connections
• Wide range of housings with various push-through openings
• Residual current range 2 – 50 A

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