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MI 3152(H) EurotestXC (2,5 kV)
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 Figure 7.15 and Figure 7.16).
Different test cable must be used for testing with MI 3152 where end voltage is 1000 V
and MI 3152H where end voltage is 2500 V. Also different test terminals are used.
The standard 3-wire test lead, Plug test cable or Plug / Tip commander can be used for
the Varistor test with end voltage 1000 V. For the 2500 V Varistor test the two wire 2.5
kV test lead should be used.
Start the measurement.
A voltage ramp starts from 50 V and rises with a slope of 100 V/s (Range parameter set
to 1000 V) or 350 V/s (Range parameter set to 2500 V). 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).
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:
Uac voltage may be directly compared with the voltage declared on tested protection
device.
Figure 7.17: Examples of varistor test result
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1.15 × √2
98
Tests and measurements
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