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need to note the clause below:- d/ s% P2 a# k5 X5 F/ r
IEC60950:
) @& h7 r0 L6 a" _/ b: H1.5.9.2 Protection of VDRs
8 N% J! b) ?9 Z. I5 Z) G5 |For protection against1 C9 L" j& E9 d& J/ y8 {
− temporary overvoltages above the maximum continuous voltage,! I2 D1 i% o8 @. }1 k# k! X6 ^
− thermal overload due to leakage current within the VDR, and
4 D5 M' N5 Y& O& J6 s1 M. G, E; q: z− burning and bursting of the VDR in the event of a short-circuit fault," C/ |9 q7 s8 u1 x
an interrupting means having an adequate breaking capacity shall be connected in series with
) M! K7 ~6 f' hthe VDR. This requirement does not apply to a VDR in a LIMITED CURRENT CIRCUIT.. Y- r, O& S- Q
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IEC60065:2 h9 b2 W* j! M6 Y
– thermal stress
+ |, I0 c( G, H: U/ C% I+ ]For apparatus with nominal MAINS voltage of <150 V, the apparatus and a test resistor
; G4 i. c8 P4 @7 ^8 s+ P1 S3 Aconnected in series with the apparatus shall be energised from an a.c. source of 250 V.
h; F8 U7 e( B: d0 TThe voltage source shall be applied for 4 h or until the circuit path through the varistor
. A8 ^0 N/ I7 I5 \3 Yopens for each of the test series resistance values: 2 000 Ω, 500 Ω, 250 Ω, 50 Ω. A
+ x( j+ f8 ? nseparate apparatus shall be used for each resistor value, unless damage from the previous
* Y- f6 ^3 o( j: U5 U# f. j ktest has been repaired.
" i% L' Y( [2 B0 |- EAt the end of each test, the apparatus shall comply with clause 11. |
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