How does the SGR Sensor, MDGF module work with Micrologic X?


30 September 2021

For the below systems as described in the MDGF instruction sheet
Please find below how the current sensor, MDGF work with Micrologic :

If a primary current of 100A passes through the SGR current sensors, then a secondary current of 0.1A wil be received by the MDGF summing module via terminal 1(J1-1) and 3(J1-3).

The MDGF summing module internally does the following calculation :

100A(rms)*0.00173 = 0.173V(rms) : this voltage can be measured on the terminal 5(J2-2) and 7(J3-1) of the MDGF summing module and it is transmitted to the terminals M2 and M3 of the micrologic Trip Unit.

The Micrologic does the following calculation : 0.173V(rms)/0.00173(rms) = 100A

The Micrologic will report the Ig trip if the current from current sensor and MDGF exceeds the Ig threshold and the tg time delay expires

Information on wiring and installation can be found from instruction sheet -

For the MTZ spare part list refer to the latest spare part catalogue -