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| DSH 418
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. L4 u) o! S( t2 K5 z9 f | Load resistance in relation to load current( [6 M+ A7 m1 P, y" z* k0 }$ N a! N4 ?
| 57.9, 57.9.1% N* \& f8 }8 m! l$ X
| 60601-1(ed.2);am1;am2+ Z; J4 h& ~' {/ K$ b
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Standard(s)- (year and edition):
2 j" c. s# [6 o+ [1 XIEC 60601-1:1988 Ed.2 Am1+Am2
0 _5 E# n% |" K8 L) r& [) OSub clause(s): 57.9, 57.9.1
* ]' l# j1 X5 ?$ Y! z+ qSheet n°: DSH-418+ |8 s/ p/ u6 B$ G
Subject: Load resistance in relation to load current
7 _4 i& H m1 OKey words: Load resistance, load current( N1 a# k2 ?$ i y
Confirmed by CTL at its 39th meeti ng, in Cologne8 } d! q$ f2 @, U f9 r% f
Question:
* B9 x c- ~* x5 i$ t; {/ GPractically the test is performed with the winding under overload connected to a resistor with$ P5 ~# j B C) g1 N, b6 ~
the resistance value that yields the correct test current in accordance with Table XX. As the
2 Y3 H' c; L4 S0 K l! ~windings get heated during the test their resistance increases and one has to decrease the6 b, \& a- E& i3 z _/ {% z
value of the load resistor to keep the current in the fused circuit in accordance with Table XX7 t- N: G( d% c, m W& j \
during the test. Since the decrease of current is a result of the increase in the winding’s" L/ V Y" {* t7 |4 A% i
temperature, it seems to be an unrealistic fault condition to keep the current in the fused circuit
3 \8 Q; h9 L! |. J' ~$ junchanged instead of keeping the load resistance unchanged.% |) z O) q& G" u+ Y) Q
Decision:: V8 \' n0 K" `( |1 {( I6 g
The test load current must be maintained at its original value8 P7 A. ]4 M5 H% R. @
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