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|  DSH 719$ p3 t$ ~3 t$ ] B8 J
- H. n0 S6 V, t8 v+ ^% }1 X# t | Construction/ r$ |% [+ H6 \- M
| 22.106; o- M$ l& c0 K7 t. y1 c( r0 ~" `
| 60335-2-21(ed.5)
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' o# h3 H4 q# i# i0 k& b9 \9 RQuestion:! ^& S; M: S; P- o( A# S
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.
9 ~$ a0 A, U2 K# |5 C3 eCan 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 ^! q" v/ N* E) ^, m- e7 _; KDecision:
- V) a$ a2 _' \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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