Tettex MIDAS 2881, Operating Instructions Manual

Page: 39 / 164

Operation Elements 29
6.5 HV GND Connection Surveillance
The HV GND connection to system ground is kept under constant surveillance. As shown in below,
relay Re1 can only close when the test system is supplied with mains power and the test object is
earthed via a separate earth connection. Therefore, the high voltage can only be switched on when
status “Grounded” is shown on the instrument side panel (and on the display as well).
Should the HV GND connection being interrupted the actual test (HV) will be switched off
immediately.
Functional principle of the safety circuit for earth connection monitoring
6.6 Safety Ground (Earthing)
Figure 15
Safety ground
connection
Wing nut ground terminal for connecting the safety ground lead to earth
ground
(connected to the instruments housing and the ground pin from the mains
connector, there is no measuring or AC supply functionality)
Side panel – Safety Ground
A separate green/yellow earth cable is provided for the purpose of safety grounding the instrument.
The Safety Ground cable should be connected to the Earthing Screw on the back of the MIDAS at
one end and to the station grounding system at the other end.
For safety reasons the earth cable should be the FIRST lead to be connected to the set and the LAST
to be disconnected.
The device under test, its tank or housing, and the MIDAS must be solidly and commonly grounded or
earthed. This also applies to any mobile equipment being tested.