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Standard(s)- (year and edition):& W% S& f$ n7 X* D2 [6 J9 A
IEC 60601-1:1988 Ed.2 Am1+Am2& Z" p9 U4 `/ a! U9 ^% }* ^
Sub clause(s): 57.9, 57.9.1
; r; r2 l3 A) Y2 l: m6 MSheet n°: DSH-418. x& z; u; Q$ H5 Y! \+ v
Subject: Load resistance in relation to load current8 t$ p; u! D& e' X- P6 f! g4 f% X
Key words: Load resistance, load current: z9 B) M# ~* _ t! B4 K. C
Confirmed by CTL at its 39th meeti ng, in Cologne' e# E& q' c8 a/ k# k9 W! I: C
Question:
6 E+ v# Q6 P: o; C$ W' _; U/ APractically the test is performed with the winding under overload connected to a resistor with- q% v6 U k9 F& \. Q b
the resistance value that yields the correct test current in accordance with Table XX. As the9 g8 e! S* a6 f3 T- W3 g
windings get heated during the test their resistance increases and one has to decrease the
( U `0 j+ N5 {# p, tvalue of the load resistor to keep the current in the fused circuit in accordance with Table XX
# C( ^3 M8 N& n, E1 gduring the test. Since the decrease of current is a result of the increase in the winding’s
, P' |7 t" f6 ]% l' f8 Qtemperature, it seems to be an unrealistic fault condition to keep the current in the fused circuit) o/ {) N/ v9 [! R. _
unchanged instead of keeping the load resistance unchanged., A! @( \# g. C, t R% P
Decision:+ M5 x6 \& n# G
The test load current must be maintained at its original value
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