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need to note the clause below:
7 D, G" [. B6 OIEC60950:
6 d' _/ |! J3 Z. O, r1.5.9.2 Protection of VDRs
6 \& @4 C Y. ~ E) D) mFor protection against$ K9 ]2 v6 c' d) j+ ~6 S+ l
− temporary overvoltages above the maximum continuous voltage,) m" d. k" a' s, n# {! ?" x
− thermal overload due to leakage current within the VDR, and# f9 K$ Q2 } G( l5 h
− burning and bursting of the VDR in the event of a short-circuit fault,
4 ?( _8 c4 L2 h1 Y$ ^an interrupting means having an adequate breaking capacity shall be connected in series with
{2 s) h/ S! k. u9 t& n3 ^; m5 sthe VDR. This requirement does not apply to a VDR in a LIMITED CURRENT CIRCUIT.7 _# K' _3 q' E' q' c+ M. V
+ {8 Z7 T8 i. H0 d; ~! O2 V9 p& l9 z
IEC60065:# x" \% R( B" A& ~/ D
– thermal stress
2 @; A% O( V6 }( GFor apparatus with nominal MAINS voltage of <150 V, the apparatus and a test resistor
4 G7 I, _8 s/ l. O1 M7 D1 G! vconnected in series with the apparatus shall be energised from an a.c. source of 250 V.; J9 h3 }; L+ |; h5 R+ t& I
The voltage source shall be applied for 4 h or until the circuit path through the varistor
. g5 Z" k9 D$ T+ t5 ?opens for each of the test series resistance values: 2 000 Ω, 500 Ω, 250 Ω, 50 Ω. A
' S' z: r) b0 V* Tseparate apparatus shall be used for each resistor value, unless damage from the previous
Q/ h0 ~' ?+ ttest has been repaired., f% J$ s) `" ^) J% v$ V* u- y0 P" J
At the end of each test, the apparatus shall comply with clause 11. |
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