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14.12 Surge suppression varistors# D' I, X& i9 C# q3 }
Surge suppression varistors used in order to prevent MAINS overvoltages coming into the
1 o" m( X' [. J0 ]6 Dapparatus shall comply with IEC 61051-2.
1 P6 F d$ V/ M% I: x8 wSuch components shall not be connected between parts connected to the MAINS and( x1 ^: P2 A. S% C& k8 Y1 p
ACCESSIBLE conductive parts or parts connected to them, except for earthed parts of6 ^6 w# o. R' D& ~' g4 X- b( l- B% h
PERMANENTLY CONNECTED APPARATUS., s' r0 T3 h: X1 v3 B2 M" o) Y6 l
Reference is made to IEC 61051-2 where the following requirements apply:
c9 R8 z2 ~6 t J" e– preferred climatic categories (2.1.1 of IEC 61051-2). V" f2 z) h$ R$ u
• maximum lower temperature: –10 °C; V* z, N1 U8 V0 `8 m1 ~) u
• minimum upper temperature: +85 °C5 a5 ?9 V$ ]) ~3 q4 O. L
• minimum duration of climatic tests: 21 days+ Y) v& N W" B8 P" E8 B9 T
– maximum continuous voltages (2.1.2 of IEC 61051-2)
$ s X% I9 w9 ~9 XThe minimum value of the maximum continuous a.c. voltage shall be 1,2 times the RATED) ~! j( E3 D. U. C3 H, _; I( Y
SUPPLY VOLTAGE of the apparatus.
. E9 H0 ?' `$ U( Q* s8 B8 T– current pulse rating (IEC 61051-2, subclause 2.1.2)
' a5 [( l% I& D/ H# eSurge suppression varistors shall withstand a combination pulse of 6 kV/3 kA with voltage
2 W# L3 ?: p8 ]" @; z# swaveform of 1,2/50 μs and current waveform of 8/20 μs.
4 C1 `# g8 E' o, n: u3 MCompliance is checked by applying the test of IEC 61051-2, group 1. After the test, the
% r9 c8 |. k+ H# gvaristor voltage (as defined in IEC 61051) shall not have changed by more than 10 % when2 _3 a/ E: K8 o) e9 ^6 X
measured with the manufacturer’s specified current. |
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