DSH 730 Abnormal operation and construction

小米

广东安规检测
有限公司提供：

小型摆管淋雨试验机

IPX5X6X7喷水试验机

1000L恒温恒湿箱

各种试验指现货

可程式恒温恒湿试验箱

水平垂直燃烧机

自动卷线器试验机

耐划痕试验机

各种灯头量规现货

灼热丝试验机现货

GB1002插头量规

IPX1-X7淋雨现货

IEC61347/UL935镇流器热试验箱

灯具防风罩

IK冲击试验机

UL498插头插座量规

VDE0620插头插座量规

稳定性试验台

家电温升测试角

针焰试验机现货

热电偶焊机现货

家电125mm试验指

E12灯头量规

无绳壶无绳电熨斗插拔寿命试验机

IEC60335试验指甲

DSH 730 4 ?3 z- K" }( }! v9 J

Abnormal operation and construction

19.11.1/2/3/4 and 22.46

60335-1(ed.4);am1;am2

" W( Y) ^/ Z- C+ {: h/ AQuestion:
(1) In the construction shown in the figure, NTC1+micro+T1 operate as a thermostat for the heating element, R. The heating element does not have integral protection. During the application of the requirements in clause 19.11.2, transistor T1is shorted and NTC2+micro+T2 operates as a thermal cut-out to comply with sub-clause 19.13.
( C0 A% a, R7 K# ua.- Are NTC2+micro+T2 considered as a PEC?
b.- If so, are the clauses 19.11.3 (additional fault), 19.11.4 (immunity) and 22.46 (software classification) applicable?
c.- Considering that the thermostat software and the thermal cut-out software are separate parts of code, what software classes are applicable to the thermostat and the thermal cut-out?
  P* O; V) p/ s0 t(2) For the same construction, the manufacturer changes the parameters of NTC2 in such a way that NTC2+micro+T2 do not operate as a thermal cut-out but as redundant thermostat at the same temperature as the normal thermostat. Under the same conditions of the test in clause 19.11.2, short circuiting of T1, the heating element operates as in normal operation to comply with sub-clause 19.13.
5 [  c4 h. _* }" Y5 m1 id- Are the electronic circuit or some of its parts considered as a PEC?
6 r  d$ U" B+ M! ~+ h6 X4 ^0 m# F  i6 Ne.- If so, are the clauses 19.11.3 (additional fault), 19.11.4 (immunity) and 22.46 (software classification) applicable?
+ L# Z; X$ b4 Y* A2 J& af- Considering that the thermostats have separated software, what software classes are applicable?
) t% o3 d7 C) ^& |9 ADecision:
, d5 ?; @0 u" A5 k2 P7 q(1)
a- Yes
; `  @9 N. O9 F; z- y) ^0 `b- All sub-clauses are applicable
% `' l5 ?$ A) O; ]# gc- Taking into account that short circuit of T2 has to be considered in 19.11.2, then the thermostat is considered as a PEC too. Software class for T2 shall be at least B, and the software class for T1 is class A, B or C.
(2)
% u6 K2 N) r! e+ m; Vd- Yes, the temperature control of the circuit (T1+T2+micro+NTC1+NTC2)is considered as a PEC
* ?& O% Q. v" y% r. F% Pe- All sub-clauses are applicable
2 ^1 O) w& C: @  F) Q  Sf- Both software have to be class B
7 s; @; _8 F+ Y
2 W( [; _. h7 E& }( g

- I4 u6 Q8 F& S