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need to note the clause below:9 C2 v% q" k$ _- V+ C+ q6 ]
IEC60950:
9 w& I) K4 d- t- Y- Q3 ~4 C, R/ F% N6 g3 q1.5.9.2 Protection of VDRs1 b6 u# b7 S8 I+ m
For protection against% p, E$ q7 o- B; ~# T
− temporary overvoltages above the maximum continuous voltage,
7 s8 f1 j5 r" [ C) [. _9 d− thermal overload due to leakage current within the VDR, and
# `, F' @1 w% ]% }( H$ f9 Z− burning and bursting of the VDR in the event of a short-circuit fault,, Z! ?8 P1 D8 ~- ~& p# L0 n
an interrupting means having an adequate breaking capacity shall be connected in series with. P) m3 c( f; V* H$ y6 l
the VDR. This requirement does not apply to a VDR in a LIMITED CURRENT CIRCUIT.# P _( I) ^: d7 g1 ?/ \
6 L# p5 r7 L1 j; [; ]7 I7 s4 r5 TIEC60065:
8 n( y9 q" {8 ?+ V– thermal stress
' I$ z3 p9 n$ K n* o% GFor apparatus with nominal MAINS voltage of <150 V, the apparatus and a test resistor5 I: `& _: {& l5 E
connected in series with the apparatus shall be energised from an a.c. source of 250 V.
e. L: W+ J0 vThe voltage source shall be applied for 4 h or until the circuit path through the varistor
! w& n, S) f- g! uopens for each of the test series resistance values: 2 000 Ω, 500 Ω, 250 Ω, 50 Ω. A
, m- w/ N) b& P2 y3 Bseparate apparatus shall be used for each resistor value, unless damage from the previous0 l# E( r# s. H2 b+ R/ g# g
test has been repaired.$ M3 U- h8 i' l2 m A
At the end of each test, the apparatus shall comply with clause 11. |
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