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need to note the clause below:# l4 S4 i$ j, h: q* f
IEC60950:
9 ]" t6 f% B" y% h( j1.5.9.2 Protection of VDRs
# X6 u S7 B) R7 \6 |, j) yFor protection against" ?* k5 @. W4 X1 Q5 I
− temporary overvoltages above the maximum continuous voltage,( k. @: O+ s5 p' \
− thermal overload due to leakage current within the VDR, and
: P* B2 K7 I. T; L& H9 X$ a) ^− burning and bursting of the VDR in the event of a short-circuit fault,
7 R. q3 g9 z2 {1 x% O/ Dan interrupting means having an adequate breaking capacity shall be connected in series with; ^8 w& B) `) M7 i( i. F4 m
the VDR. This requirement does not apply to a VDR in a LIMITED CURRENT CIRCUIT.
# Q8 @; U) L7 [: K v' A; y+ v9 X
IEC60065:! p# i5 `% p) v' H
– thermal stress' q; v; {' S$ [" j1 I9 W
For apparatus with nominal MAINS voltage of <150 V, the apparatus and a test resistor
2 q* ]! O x4 X/ c9 T9 tconnected in series with the apparatus shall be energised from an a.c. source of 250 V.& [" H* C9 N, G, Y3 S
The voltage source shall be applied for 4 h or until the circuit path through the varistor- T) q! S6 J5 m$ f
opens for each of the test series resistance values: 2 000 Ω, 500 Ω, 250 Ω, 50 Ω. A3 [. w# \! b# d- T
separate apparatus shall be used for each resistor value, unless damage from the previous8 x% P" t# ^$ ?1 x
test has been repaired.
% }4 B: t" Y: r& C8 ^9 h" D* l! x, DAt the end of each test, the apparatus shall comply with clause 11. |
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