MI 3110 EurotestIM
Measurements
– a.c. LV IT installations
28
Note:
❑
High fluctuations of mains voltage can influence the measurement results (the
noise sign
is displayed in the message field). In this case it is recommended
to repeat few measurements to check if the readings are stable.
5.2.2 Voltage drop
The voltage drop is calculated based on the difference of line impedance at connection
points (sockets) and the line impedance at the reference point (usually the impedance
at the switchboard).
Circuits for measurement of voltage drop
Figure 5.9: Voltage drop measurement in IT system
– connection of 3-wire test lead
Voltage drop measurement procedure
Step 1: Measuring the impedance Zref at origin
❑
Select the
ΔU
sub-function using the function selector keys and
/
keys.
❑
Select test
parameters
(optional).
❑
Connect
test cable to the instrument.
❑
Connect
the test leads to the origin of electrical installation (see Figure 5.9).
❑
Press the
CAL
key to perform the measurement.
Step 2: Measuring the voltage drop
❑
Select the
ΔU
sub-function using the function selector keys and
/
keys.
❑
Select test
parameters
(Fuse type must be selected).
❑
Connect
3-wire test lead or mains measuring cable to the instrument.
❑
Connect
the test leads or mains measuring cable to the tested points (see
❑
Press the
TEST
key to perform the measurement.
❑
Store
the result by pressing the MEM key (optional).
