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|  DSH 7193 f! P+ g. T6 T
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| 22.106% X2 s6 X) y8 G: E
| 60335-2-21(ed.5)
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Question:$ B- {/ `% E8 j4 v+ g' k
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.
# B; N. l6 @/ j3 g4 ?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?
2 ~! o# w6 \2 C; [- rDecision:/ Z6 Z% q' g% p3 p4 j
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..* d b5 D( ~5 H3 @
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发表于 2012-9-8 12:11
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