小米 发表于 2012-11-7 19:13

DSH 643 Measured limiting voltage


http://decisions.iecee.org/icons/ecblank.gif DSH 643

Measured limiting voltage
7.5 a), 7.5.4 a)
61643-1(ed.2)


Standard(s)-(year and edition):
IEC 61643-1, 2nd edition, 2005-03
Sub clause(s): 7.5 a)7.5.4 a)
DSH- 643
Subject:
Measured limiting voltage
Key words:
- measured limiting voltage
- protection level
- energised testing
Approved by the 45th CTL plenary meeting 2008
Question:
Testing of one port SPDs according to test class III (Type 3):
Should the test to measure the limiting voltage with the combination wave be performed with the SPD being energised at Uc or without energisation?
Rationale:
Clause 7.5 a) of the standard requires:
All one-port SPDs shall be tested unenergized. …
Clause 7.5.4 of the standard requires:
a) The combination wave will be applied to an energized SPD, with the mains voltage at Uc.
As testing energised may give higher measurement results, the test should be performed energised
Decision:
The test shall be performed with the SPD being energised at Uc.


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