METREL MI 3290, Instruction Manual

Page: 96 / 162

MI 3290 Earth Analyser Tests and Measurements
96
11.5 DC Resistance [R]
DC
Resistance Measurement Test
Mode Test
Method Limit Filter Test
Current
R
Ω - Meter (200mA) single 2-wire yes DC 200 mA
Ω - Meter (7mA) cont. 2-wire yes DC 7 mA
Table 11.52: Available DC Resistance measurements in the MI 3290
11.5.1
Ω - Meter (200 mA) Measurement
The resistance measurement is performed in order to assure that the protective measures
against electric shock through earth bond connections are effective. The resistance
measurement is performed with DC current of 200 mA.
I
dc
C1
C2
MI 3290 Earth Analyser
G
V
A
Rx
2-wire
Figure 11.53:
Ω - Meter (200 mA) example (2-wires)
In the example following resistance is measured:
R =
𝑈
𝐷𝐶
[𝑉]
𝐼
𝐷𝐶
[𝐴]
= [𝛺]
where:
R
....................................... Resistance
I
dc
...................................... Injected DC test current between C1 and C2 terminals
U
dc
.................................... Measured DC voltage between C1and C2 terminals
Test can be
started from the Ω - Meter (200 mA) measurement window. Before carrying out a
test the following parameter (Limit (R)) can be edited.
Figure 11.54:
Ω - Meter (200 mA)
measurement menu
Figure 11.55: Example of
Ω - Meter (200 mA) measurement result
Test parameters for
Ω - Meter (200 mA):
Test Method
Test method [2 - wire]
Limit (R) Limit value selection: [
OFF, 0.1 Ω – 40 Ω]