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| DSH 418/ x9 v: U7 z; e6 E+ q
$ X! ]3 M9 t6 d9 u. ?; n | Load resistance in relation to load current9 N9 `* J# b4 u/ M5 w* x' o
| 57.9, 57.9.1# _- C& X# V1 ?' Q
| 60601-1(ed.2);am1;am2
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% s" [5 W. Q: A" Y7 _Standard(s)- (year and edition):6 b; C3 f- D/ B' [* U( ^/ Y) a
IEC 60601-1:1988 Ed.2 Am1+Am22 z# s% A$ @" |3 P% G
Sub clause(s): 57.9, 57.9.1
2 P6 z+ n. \! b- s+ ?! m! hSheet n°: DSH-418
0 R, J2 A7 O8 ?) ~9 C5 {2 Z- x$ b6 ASubject: Load resistance in relation to load current
D+ P4 k5 E/ f. m" E! k; tKey words: Load resistance, load current q$ q2 u8 F3 O$ h* \. ?0 M7 o2 T
Confirmed by CTL at its 39th meeti ng, in Cologne
7 T& L: r1 q. P% k2 \Question:
. D; m5 H% I7 B! p9 MPractically the test is performed with the winding under overload connected to a resistor with! f7 E. @( q. }9 J- C" M" M |8 n
the resistance value that yields the correct test current in accordance with Table XX. As the, l! i% \( u) w2 M7 B/ A: V+ U
windings get heated during the test their resistance increases and one has to decrease the6 j9 r R$ r' |) k
value of the load resistor to keep the current in the fused circuit in accordance with Table XX; R$ Q0 y |6 I3 c
during the test. Since the decrease of current is a result of the increase in the winding’s' `/ w7 `: ]+ |( _+ o+ d$ \
temperature, it seems to be an unrealistic fault condition to keep the current in the fused circuit
) e+ ^- x) B3 junchanged instead of keeping the load resistance unchanged., L! c; J4 R* U* ?
Decision:
4 q( K5 N8 M, Q! G0 L$ `2 P: sThe test load current must be maintained at its original value
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