小米 发表于 2012-11-5 11:06

DSH 418 Load resistance in relation to load current


http://decisions.iecee.org/icons/ecblank.gif DSH 418

Load resistance in relation to load current
57.9, 57.9.1
60601-1(ed.2);am1;am2


Standard(s)- (year and edition):
IEC 60601-1:1988 Ed.2 Am1+Am2
Sub clause(s): 57.9, 57.9.1
Sheet n°: DSH-418
Subject: Load resistance in relation to load current
Key words: Load resistance, load current
Confirmed by CTL at its 39th meeti ng, in Cologne
Question:
Practically the test is performed with the winding under overload connected to a resistor with
the resistance value that yields the correct test current in accordance with Table XX. As the
windings get heated during the test their resistance increases and one has to decrease the
value of the load resistor to keep the current in the fused circuit in accordance with Table XX
during the test. Since the decrease of current is a result of the increase in the winding’s
temperature, it seems to be an unrealistic fault condition to keep the current in the fused circuit
unchanged instead of keeping the load resistance unchanged.
Decision:
The test load current must be maintained at its original value


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