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|  DSH 719
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| Construction
5 @+ k: @( o& T7 i3 b- j | 22.106
+ p/ i" Q; e7 J) }2 L- E/ n | 60335-2-21(ed.5)
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Question:7 x D+ h3 D- n/ o8 {) A. V; O
Sub-clause 22.106 of standard IEC 603325-2-21:2002 states that, a closed water heater shall incorporate a thermal cut-out providing all-pole disconnection which operates independently from the thermostat.
1 O* t1 z( Y/ s( H5 ^6 HCan the thermal cut-out and thermostat control the same contactor, when a contactor is used or are two contactors needed, one controlled by the thermal cut-out and one controlled by the thermostat?- t3 K$ r5 R( [( V7 A8 P! _( Q
Decision:
4 T" \( ~- I6 n3 i6 K4 LTwo contactors or relays must be used because the contactor or relay may not operate if one set of independent contacts welds closed. See also 19.14 in IEC 60335-1 Ed 4.2..4 K7 y7 G' ^: y
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发表于 2012-9-8 12:11
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