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need to note the clause below:
( ?0 D3 {$ H& s* P' \2 ^- XIEC60950:1 h* q! q, e2 H( _; b( y6 D
1.5.9.2 Protection of VDRs& P$ r" S: w& ?7 B" R
For protection against; D. g2 {0 U9 a) }' c7 w. m! k! N/ q
− temporary overvoltages above the maximum continuous voltage,
6 o3 f% W2 s! H8 ~: I8 a( e− thermal overload due to leakage current within the VDR, and: ~0 ~0 y9 y& m
− burning and bursting of the VDR in the event of a short-circuit fault,2 u3 `4 |- [5 w/ v& K
an interrupting means having an adequate breaking capacity shall be connected in series with7 C) M+ {- m! b q
the VDR. This requirement does not apply to a VDR in a LIMITED CURRENT CIRCUIT.' B0 O4 m( J# s) X
8 d9 K0 [% ?# W$ ]1 N) w) ?( C
IEC60065:7 m7 M: D: p2 ?4 h1 B4 }
– thermal stress+ H$ g2 n+ ^0 Y* ~
For apparatus with nominal MAINS voltage of <150 V, the apparatus and a test resistor2 O7 `% C7 Z" z7 e4 }( d
connected in series with the apparatus shall be energised from an a.c. source of 250 V.
! b$ E4 u% l" o/ u) b! U; F% PThe voltage source shall be applied for 4 h or until the circuit path through the varistor
- j& z3 M( T( x% r/ n7 |% P# Ropens for each of the test series resistance values: 2 000 Ω, 500 Ω, 250 Ω, 50 Ω. A
1 m* e/ s% Z- |* a& [9 b, n" K) yseparate apparatus shall be used for each resistor value, unless damage from the previous
# m5 T/ \* P. G# v" jtest has been repaired.8 ]% t* d% F. S5 D4 j( F2 A
At the end of each test, the apparatus shall comply with clause 11. |
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