MI 3155
Eurotest
XD
Test and measurements
109
Figure 7.19: Connection of 2.5 kV test lead (Range: 2500 V)
Measurement procedure
Enter the
Varistor test
function.
Set test parameters / limits.
Connect test cable to the instrument.
Connect test leads to object under test (see
Different test cable must be used if testing at Range: 1000 V or 2500 V. Also different
test terminals are used.
The standard 3-wire test lead, or Tip commander can be used for the Varistor test when
testing at Range: 1000 V. If Range: 2500 V is selected, the two wire 2.5 kV test lead
should be used for the Varistor test.
Start the measurement.
The measurement ends when the defined end voltage is reached or if the test current
exceeds the value of 1 mA.
After the measurement is finished wait until tested item is fully discharged.
Save results (optional).
Figure 7.20: Examples of varistor test result
Measurement results / sub-results
Uac
Calculated a.c. breakdown voltage
Udc
Breakdown voltage
Meaning of the Uac voltage
Protection devices intended for a.c. network are usually dimensioned approx. 15 % above peak
value of the nominal mains voltage. The relation between Udc and Uac is following:
