Testboy TV 455 - Voltage Drop

®
TV 450/455 Line impedance
47
Un ........Nominal L-N or L1-L2 voltage (see table below),
ksc .......Correction factor for Isc (see chapter 4.2.6).
U
n
Input voltage range (L-N or L1-L2)
110 V
(93 V ≤ U
L-PE
< 134 V)
230 V
(185 V ≤ U
L-PE
≤ 266 V)
400 V
(321 V < U
L-N
≤ 485 V)
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.
5.6.2 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 for voltage drop
Figure 5.30: Phase-neutral or phase-phase voltage drop measurement – connection of
plug commander and 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 switch and / keys.
 Select test parameters (optional).
 Connect test cable to the instrument.
 Connect the test leads to the origin of electrical installation (see figure 5.30).
 Press the CAL key to perform the measurement.