|
|
5.12 For heating appliances and combined appliances, when it is specified that the
- w4 }! a/ ]5 @' B4 Jappliance has to operate at a power input multiplied by a factor, this applies only to heating
. K+ d5 m, F3 m2 [elements without appreciable positive temperature coefficient of resistance.
% n* y+ a% M: Y6 A; a8 fFor heating elements with appreciable positive temperature coefficient of resistance, other than& v: u/ q" @/ Y
PTC heating elements, the supply voltage is determined by supplying the appliance at rated
% H5 C4 z2 a9 G+ i L: b% j3 S- [voltage until the heating element reaches its operating temperature. The supply voltage is then9 ]+ n4 C, y8 O# _. t
Copyright International Electrotechnical Commission) B5 i7 P, C& h% _% r- q
rapidly increased to the value necessary to give the power input required for the relevant test,
5 k9 `( r/ o1 q, }$ ythis value of the supply voltage being maintained throughout the test.
% y) G' c9 o4 g9 oNOTE In general, the temperature coefficient is considered to be appreciable if, at rated voltage, the power input
3 p8 `! C, Z( y: g, A7 H7 tof the appliance in cold condition differs by more than 25 % from the power input at operating temperature.5 h9 D+ k! V/ E$ k) b7 l
5.13 The tests for appliances with PTC heating elements and for heating appliances and
$ r P% @' V' [. r4 l- [4 bcombined appliances where the heating elements are supplied via a switch mode power/ \4 I4 `- l+ G
supply are carried out at a voltage corresponding to the specified power input.+ b, P9 \( Z; r8 j& P7 T
When a power input greater than the rated power input is specified, the factor for multiplying
5 G3 @; z: @2 F$ R7 ythe voltage is equal to the square root of the factor for multiplying the power input. |
|
/1 
|关于安规|小黑屋|安规QQ群|Archiver|手机版|安规网
( 粤ICP13023453-10 ) 
窥视卡
雷达卡
发表于 2012-10-14 22:14
显身卡