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| DSH 418
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/ S, {* s0 O2 j1 }, m | Load resistance in relation to load current
1 [- D9 z4 E4 e: h7 o+ r | 57.9, 57.9.1/ I9 c: T2 X2 T" J2 ]3 b3 e$ I, z
| 60601-1(ed.2);am1;am2, S7 E! h' b" @+ L
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Standard(s)- (year and edition):, o5 A9 A. C. s% R2 i
IEC 60601-1:1988 Ed.2 Am1+Am2; i; H) e9 @) X8 Q; [6 D
Sub clause(s): 57.9, 57.9.1
- ~% \# X- c% t; m) p+ D; {; Y P' bSheet n°: DSH-418
7 g B7 m+ d8 GSubject: Load resistance in relation to load current
; B3 n1 X) I+ o+ ~3 _3 o4 g( cKey words: Load resistance, load current2 |5 n/ {4 {6 C
Confirmed by CTL at its 39th meeti ng, in Cologne, h7 A4 G, D7 @8 I5 T* B0 M
Question:, i" ]" m3 N# {2 B# h; Q/ U
Practically the test is performed with the winding under overload connected to a resistor with0 D: {" y5 y5 h9 Z |
the resistance value that yields the correct test current in accordance with Table XX. As the& Y5 X8 I: N+ Q) N+ s
windings get heated during the test their resistance increases and one has to decrease the3 V0 P4 ?$ V: G8 |7 y# K0 ]
value of the load resistor to keep the current in the fused circuit in accordance with Table XX" A% j. r- G8 D; S
during the test. Since the decrease of current is a result of the increase in the winding’s; G2 X4 O6 v6 o
temperature, it seems to be an unrealistic fault condition to keep the current in the fused circuit
- A' k/ D' J" B a& J C: _unchanged instead of keeping the load resistance unchanged./ X; R' S& Z* Y# | e/ A( i
Decision:) b5 V# m" F4 w' l4 v5 {
The test load current must be maintained at its original value$ E; q6 ~# i% F N! |3 ^" H
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