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|  DSH 719* y* d9 u, \9 O8 @+ \
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| 22.106- p P* B3 v% e7 B7 o
| 60335-2-21(ed.5)
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Question:
3 S. k# _& A, z( `' rSub-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./ W# \/ b0 a, o+ s& n
Can 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?7 K$ z4 h* d2 @/ ]1 C6 q
Decision:8 T- z; T3 O( b+ i/ Z
Two 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..
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发表于 2012-9-8 12:11
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