DEB71DM24A5 Carlo Gavazzi

DEB71DM24A5, Monitoring relay and differential protection, DEB71DM24A5, DEB71 is an adjustable differential protection relay that, together with magnetothermic switches and CTG differential current transformers, provides protection to people against the risk of electrocution and to the installation against the risk of fire by interrupting the power supply of the electrical network in the case of faulty lines or loads where current to ground may occur . The setpoint of the ground leakage current is adjustable. DEB71 has two SPDT relay outputs, a pre-alarm that is activated at 60% of the setpoint and an alarm one, which will be used to disconnect the associated power line and avoid accidents., DEB71DM24A5, DEB71 is a residual current detection relay (leakage current to ground) used to detect those cases in which there is a failure in an electrical circuit that produces a shunt from current to ground. The conductors of the supervised circuit (except the protective ground wire, as shown in the proposed connection diagrams) pass through a differential current transformer. Before the start of operation it is necessary to configure the necessary IΔn leakage activation current with a value between 30 mA and 5 A (DEB71DM24A5) or between 300 mA and 30 A (DEB71DM24A30). 30 mA are commonly used for the protection of people from electrocution. 300 mA are commonly used to provide protection against the risk of fire. A delay of up to 5 s can also be set, not recommended for protection against electrocution. Once the adjustment is complete, the front cover can be closed and sealed to prevent possible manipulations. Normal operation When the system is powered the green LED ON lights up. If the current flowing in the direction of the load is the same as the current from the load, the result in the differential current transformer will be zero. The other LEDs will be off, both relays will be activated and the external magnetothermic will have the contacts closed. Alarm detection In case of diversion of leakage current to ground in the load or in the supervised power line, the current coming from the load will be lower than that supplied. This imbalance will produce a current at the output of the differential current transformer. This current will be proportional to the leakage current. If the leakage current is less than 20% of the configured IΔn alarm value, no indication will be displayed. When the leak is between 20% and 40%, the green L1 LED will light up. Between 40% and below 60% the yellow L2 LED will light up. Above 60% the yellow L3 LED lights up. At this time the pre-alarm LED will light up: LED 4 will light up and relay output 2 will deactivate, closing terminals 21 and 22. When the leakage current increases above 80% of the configured value, the alarm will be activated after the time Δt. The red LED "AL" will light up, output 1 will be deactivated (closing terminals 11 and 12). The external magnetothermic will open, disconnecting the load from the power. Reset Once the cause of the failure has been corrected, you can restore operation by pressing the R button on the front panel of the device or by pressing the remote R/T button. Test The integrity of the system must be checked periodically by pressing the T button on the front panel of the device. You can also do this by pressing the remote R/T button for more than 2 s.