MI 3110 EurotestIM
Measurements
– a.c. LV IT installations
25
Voltage measurement procedure
❑
Select the
VOLTAGE TRMS
function using the function selector keys.
❑
Connect
test cable to the instrument.
❑
Connect
test leads to
and
❑
Store
voltage measurement result by pressing the MEM key (optional).
Measurement runs immediately after selection of
VOLTAGE TRMS
function.
Figure 5.4: Examples of voltage measurement in IT system
Displayed results for single phase IT system:
U12 .......... voltage between phase conductors,
U1pe ........ voltage between phase 1 and protective conductor,
U2pe ........ voltage between phase 2 and protective conductor,
f ............... frequency.
Displayed results for three-phase IT system:
U12 .......... voltage between phases L1 and L2,
U13 .......... voltage between phases L1 and L3,
U23 .......... voltage between phases L2 and L3,
1.2.3 ........ correct connection
– CW rotation sequence,
3.2.1 ........ invalid connection
– CCW rotation sequence,
f ............... frequency.
