PERMANENT CONNECTION CHECK An important feature of the DELTA series is the permanent control of the connection circuit between the differential relay and the toroid. When any anomaly is detected in the connection between the toroid and the relay, the protection intervenes automatically, without having to wait for the periodic check to be carried out with the test button.

AT ADJUSTMENT OF THE TRIP TIME The adjustment of the tripping time Δt makes this series the ideal solution for creating selective protection systems; the IΔn current regulation allows people and goods to be protected against unwanted or dangerous dispersions.

VERSION WITH HARMONIC COMPONENTS FILTER With the evolution of system requirements and the introduction of devices equipped with power electronics in systems, the F models were created, with harmonic component filter for heavily disturbed systems.

Differential relay type B
The type B differential relay is a device, compliant with standard IEC 60947-2 annex M, capable of detecting sinusoidal differential alternating currents or unidirectional pulsating DC currents or direct differential currents, which could be harmful or dangerous. The residual current relay is in turn connected to a special closed core TDB toroid, available in 4 sizes, which detects the leakage currents in the systems. The associated circuit-breaker is tripped by means of an undervoltage release (UVR) or current shunt release (ST). The Delta D2-b relays with the relative toroids, in combination with the Megatiker BTicino circuit breakers and relative release coils have been certified for additional protection against direct contacts.