HT instruments М75 - Manual (Page 39)

M72 - M73 - M74 - M75
EN - 37
4.16. AUTO: AUTOMATIC CYCLE OF MEASUREMENTS (M74, M75)
This function permits to test an electrical plant in a completely automatic way without any
intervention of the operator.
CAUTION
 Testing an RCD involves the tripping of the RCD itself. Therefore, before
taking this measurement, make sure that no loads are connected to the
RCD under test to avoid damaging them
 Disconnect all loads connected to the RCD as they could add further leakage
currents to those moved by the instrument, thus nullifying the test results.
Fig. 14: Connection of the instrument’s terminals during AUTO test
1. Turn on the instrument
2. Press the arrow keys to select AUTO
3. By pressing MODE/PEAK select the test current among the possible values 30mA,
30mA x5, 100mA, 300mA which turn cyclically at each key pressure
CAUTION
Pay attention when setting the test current of the RCD to make sure that the
correct one is selected. In case a higher current than the nominal one of the
device under test is selected, the RCD would be tested at a higher current
than the correct one, thus favouring a quicker tripping of the RCD itself.
4. Insert the black and green cables in the corresponding input terminals of the
instrument. If necessary insert the alligator clips on the test probes or use the shuko
cable
5. Connect the green cable to the protective conductor (earth) and the black cable to the
phase conductor (Fig. 14) or insert the Shuko cable in a power socket
6. Keep GO pressed for at least one second, the instrument performs measurements
without any intervention of the operator in the following sequenze: Ra (15mA), RCD,
M
 (phase to earth)
CAUTION
The message “Measuring” on the display means that the instrument is
measuring. During this phase never disconnect test leads.