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need to note the clause below:
3 n( k. p) X- }: d3 n% b- pIEC60950:9 O$ ^9 e$ l# \8 S; J
1.5.9.2 Protection of VDRs# ?/ X6 R' e4 G' A# M& w* }
For protection against
8 y1 O6 F: i; g% p; ?− temporary overvoltages above the maximum continuous voltage,
6 r6 i% H: V7 ~5 d7 u3 k− thermal overload due to leakage current within the VDR, and
8 i* R0 r4 B0 R− burning and bursting of the VDR in the event of a short-circuit fault,7 U$ X( B2 l4 b }9 Q
an interrupting means having an adequate breaking capacity shall be connected in series with
+ S- b1 {* l7 p8 W4 x: ]3 \the VDR. This requirement does not apply to a VDR in a LIMITED CURRENT CIRCUIT.
& w6 m# j' j2 P% N# D8 x) V1 n, O
! V( ^9 s& t* bIEC60065:
9 s" J$ h2 u5 N1 C' C- [6 B+ f– thermal stress
. Y; `& Z: |6 \/ v: \2 mFor apparatus with nominal MAINS voltage of <150 V, the apparatus and a test resistor) q8 ]0 u0 O) u) l
connected in series with the apparatus shall be energised from an a.c. source of 250 V.9 {2 { E' N" u9 X4 d2 k, z
The voltage source shall be applied for 4 h or until the circuit path through the varistor
% ?6 e! j3 H. m8 J o) Iopens for each of the test series resistance values: 2 000 Ω, 500 Ω, 250 Ω, 50 Ω. A
3 v7 R* P) @9 Mseparate apparatus shall be used for each resistor value, unless damage from the previous: q( z: K0 z- t/ p! n A
test has been repaired.
" D! d8 v: p" W6 [3 ?) _At the end of each test, the apparatus shall comply with clause 11. |
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