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need to note the clause below:
0 r+ k: Q$ h' m8 r# ~( FIEC60950:
1 |1 m0 w! I H! t8 t0 [+ H" ]1.5.9.2 Protection of VDRs
/ @) d8 a U, j/ c2 }) w- B1 SFor protection against
& |0 g+ J3 ]. k/ ^− temporary overvoltages above the maximum continuous voltage," k( h% o- y4 K/ h# a+ s9 U
− thermal overload due to leakage current within the VDR, and
" `. h; t3 c$ i9 f0 `! U( W$ s− burning and bursting of the VDR in the event of a short-circuit fault,
2 I+ W; z9 m0 I% kan interrupting means having an adequate breaking capacity shall be connected in series with
: s4 \: l/ }8 H- y) t# x: gthe VDR. This requirement does not apply to a VDR in a LIMITED CURRENT CIRCUIT." ]0 I# w) b- s) B6 N
! Y! K {) n! Q" _
IEC60065:
* Q+ d9 L4 Y) y* B– thermal stress
6 z$ q4 w! }$ m" q" I6 k4 L0 s/ ZFor apparatus with nominal MAINS voltage of <150 V, the apparatus and a test resistor* Q D: H4 a1 T; C6 a% z) j
connected in series with the apparatus shall be energised from an a.c. source of 250 V.2 V; A [) G: ?4 n6 B
The voltage source shall be applied for 4 h or until the circuit path through the varistor, }# r7 ]8 W" n( |$ d
opens for each of the test series resistance values: 2 000 Ω, 500 Ω, 250 Ω, 50 Ω. A4 J/ m( L( j6 h0 ?; o! |
separate apparatus shall be used for each resistor value, unless damage from the previous
6 e5 q) _: B( d$ Dtest has been repaired.
% Q7 Q# s: ^, uAt the end of each test, the apparatus shall comply with clause 11. |
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