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need to note the clause below:
/ Q' e$ l5 A% r% x) g4 q0 X6 ~1 eIEC60950:
- [1 j! \7 I6 t, v! y8 H1.5.9.2 Protection of VDRs' v1 l* P2 f* K8 G
For protection against
( S$ [* W( d Z0 }− temporary overvoltages above the maximum continuous voltage,! y# H, [5 v! p7 ?+ Y
− thermal overload due to leakage current within the VDR, and
+ V1 f$ M( M% n8 e! M8 T8 a− burning and bursting of the VDR in the event of a short-circuit fault,
( L: u% k! o2 W) fan interrupting means having an adequate breaking capacity shall be connected in series with& Y3 ~1 N6 P r# e. O/ F( F0 h
the VDR. This requirement does not apply to a VDR in a LIMITED CURRENT CIRCUIT.
. N- ~3 x- j Q9 [" ^) i
; E8 c% }% L6 K' `* y0 HIEC60065:
% l" {4 P/ S# X, L– thermal stress. k3 Z' w9 C% ^) s
For apparatus with nominal MAINS voltage of <150 V, the apparatus and a test resistor
! T3 t, H9 j) m, W% w" sconnected in series with the apparatus shall be energised from an a.c. source of 250 V.# \$ G4 H. L1 w G+ _
The voltage source shall be applied for 4 h or until the circuit path through the varistor$ j# }6 M; M' j- a) B; g1 c
opens for each of the test series resistance values: 2 000 Ω, 500 Ω, 250 Ω, 50 Ω. A6 w% i( w; n$ @! {0 W. D3 O, {
separate apparatus shall be used for each resistor value, unless damage from the previous
* {1 Y* I4 J/ A9 \) i) Stest has been repaired.
5 `8 d4 W; r& M. a1 @) b7 `. n) [, dAt the end of each test, the apparatus shall comply with clause 11. |
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