|
|
5.12 For heating appliances and combined appliances, when it is specified that the# ]- o. v0 j' b$ [# Z
appliance has to operate at a power input multiplied by a factor, this applies only to heating
& t; S& h9 f/ ?& Selements without appreciable positive temperature coefficient of resistance.' k; T1 W7 H& N* n7 Q( u, a
For heating elements with appreciable positive temperature coefficient of resistance, other than2 q" c& b* w! a2 e7 l8 _
PTC heating elements, the supply voltage is determined by supplying the appliance at rated
* r- x$ d" w( d8 O' V# Y/ K2 P, \voltage until the heating element reaches its operating temperature. The supply voltage is then
2 W) F1 {: U/ c6 u: q7 SCopyright International Electrotechnical Commission
+ H" B$ n( P/ R9 K c4 xrapidly increased to the value necessary to give the power input required for the relevant test,
9 L. ^( D |. c1 h6 G7 X" Sthis value of the supply voltage being maintained throughout the test.8 f9 H- C) k5 t% p. A5 c( {7 w) t
NOTE In general, the temperature coefficient is considered to be appreciable if, at rated voltage, the power input, t" m, T3 @& J9 l
of the appliance in cold condition differs by more than 25 % from the power input at operating temperature. Z; G, U. W2 ]+ J9 ?
5.13 The tests for appliances with PTC heating elements and for heating appliances and% t5 e4 d- a6 C5 o" y$ p0 e
combined appliances where the heating elements are supplied via a switch mode power
3 j1 ~2 x( x6 ?; O' @" M& Rsupply are carried out at a voltage corresponding to the specified power input.
! k$ u$ B5 ]* D' W+ vWhen a power input greater than the rated power input is specified, the factor for multiplying) K9 B( C! \- W) R
the voltage is equal to the square root of the factor for multiplying the power input. |
|
|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