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14.12 Surge suppression varistors9 J8 H; w9 v6 A0 L1 V
Surge suppression varistors used in order to prevent MAINS overvoltages coming into the
$ P0 k( F' F+ C* l: Gapparatus shall comply with IEC 61051-2.
; p/ w" _& x2 h' ~Such components shall not be connected between parts connected to the MAINS and3 d0 R5 ^4 ?0 i9 f
ACCESSIBLE conductive parts or parts connected to them, except for earthed parts of: t6 r; U+ _+ R/ g. ]5 v
PERMANENTLY CONNECTED APPARATUS.3 c9 _9 G9 u. v. U6 C' g6 X) T/ Q! S
Reference is made to IEC 61051-2 where the following requirements apply:
! w1 a: {& u h) ^– preferred climatic categories (2.1.1 of IEC 61051-2)
* Q+ ^0 c: ]1 N9 N• maximum lower temperature: –10 °C( z C7 j; g: L0 }5 O9 ^
• minimum upper temperature: +85 °C
" |) |% s% `- {9 M; H3 Q• minimum duration of climatic tests: 21 days
6 ]1 j) a" I! n7 }- [' V2 R* ~– maximum continuous voltages (2.1.2 of IEC 61051-2)' k& p5 Y# r g# ` `+ {1 ?
The minimum value of the maximum continuous a.c. voltage shall be 1,2 times the RATED
: T5 X3 f6 ^2 BSUPPLY VOLTAGE of the apparatus.
8 E4 |& |/ n' ?4 `, T. o6 G; Q– current pulse rating (IEC 61051-2, subclause 2.1.2)
0 ~( j$ {6 w! }4 n1 [5 a5 QSurge suppression varistors shall withstand a combination pulse of 6 kV/3 kA with voltage
$ U+ j7 h' ?# O' L/ Qwaveform of 1,2/50 μs and current waveform of 8/20 μs.
' ~- { ]3 p! _3 \: L2 a) SCompliance is checked by applying the test of IEC 61051-2, group 1. After the test, the
- y9 T0 [) {; r. Gvaristor voltage (as defined in IEC 61051) shall not have changed by more than 10 % when% [1 W9 y7 `, S# _# K/ Q/ s7 p
measured with the manufacturer’s specified current. |
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