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14.12 Surge suppression varistors
- d- h, S% K- S$ @* q+ l, hSurge suppression varistors used in order to prevent MAINS overvoltages coming into the
) A; M! I4 I- y; T( Y/ qapparatus shall comply with IEC 61051-2.: n4 Q/ P9 i9 u5 f* c5 A* K
Such components shall not be connected between parts connected to the MAINS and5 F+ j' `9 a+ V: A( o
ACCESSIBLE conductive parts or parts connected to them, except for earthed parts of
$ c0 m# W. V- d+ X; u# I ZPERMANENTLY CONNECTED APPARATUS.
3 R8 E Q2 R/ LReference is made to IEC 61051-2 where the following requirements apply:
4 k: | {# E/ P7 l2 C9 D– preferred climatic categories (2.1.1 of IEC 61051-2)
5 ]+ x* b6 f) N2 G4 Q# ^• maximum lower temperature: –10 °C
8 J0 l( F) s& q( j1 z& Y+ q* p. R$ R• minimum upper temperature: +85 °C- L; H" @9 o- J+ h1 f8 V9 h
• minimum duration of climatic tests: 21 days# Z6 m0 j8 c3 }2 u9 M s; K
– maximum continuous voltages (2.1.2 of IEC 61051-2)
7 g: m; g, ]1 Y0 M- m/ I$ j* bThe minimum value of the maximum continuous a.c. voltage shall be 1,2 times the RATED; d @/ X/ G" J+ {4 R2 U
SUPPLY VOLTAGE of the apparatus.( N& L! v5 i' `/ d( c1 z/ m/ A/ T5 \
– current pulse rating (IEC 61051-2, subclause 2.1.2)
, h2 d; G$ P" e0 A MSurge suppression varistors shall withstand a combination pulse of 6 kV/3 kA with voltage: b( p t" A0 l' s8 Q. S+ W( G
waveform of 1,2/50 μs and current waveform of 8/20 μs.
8 p+ C# t- c, n' {8 Y/ }& C( vCompliance is checked by applying the test of IEC 61051-2, group 1. After the test, the3 S. g- }5 O& P3 R
varistor voltage (as defined in IEC 61051) shall not have changed by more than 10 % when7 f; i ~+ \1 U
measured with the manufacturer’s specified current. |
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