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5.12 For heating appliances and combined appliances, when it is specified that the
4 {# B2 n: c7 {( g5 T5 Happliance has to operate at a power input multiplied by a factor, this applies only to heating. P7 r( Q" Q/ M0 \, h* v/ t
elements without appreciable positive temperature coefficient of resistance.( |+ r4 a$ U5 ]/ K
For heating elements with appreciable positive temperature coefficient of resistance, other than
/ \, m" P/ E' b" a0 F1 n' t+ [' G% TPTC heating elements, the supply voltage is determined by supplying the appliance at rated
1 n; e$ n. V& E5 v8 q" b( U8 pvoltage until the heating element reaches its operating temperature. The supply voltage is then( Z6 O- ^4 ~" p ?8 e
Copyright International Electrotechnical Commission
9 v7 a0 g1 M& R( W. P, Irapidly increased to the value necessary to give the power input required for the relevant test,
' L9 ]9 m0 U3 p5 H0 Q0 _this value of the supply voltage being maintained throughout the test.1 l) C6 a3 f$ @! Y$ T4 z0 z0 Y
NOTE In general, the temperature coefficient is considered to be appreciable if, at rated voltage, the power input4 P( M. P) |+ e* `+ E: e
of the appliance in cold condition differs by more than 25 % from the power input at operating temperature.
+ [5 s8 P8 d0 w* N6 D5.13 The tests for appliances with PTC heating elements and for heating appliances and2 w1 f) x# y/ l8 v! D
combined appliances where the heating elements are supplied via a switch mode power4 d9 z+ t+ ]1 j( ^
supply are carried out at a voltage corresponding to the specified power input.4 o* w6 X, c c e0 N5 P/ M- j9 ~
When a power input greater than the rated power input is specified, the factor for multiplying
, V* L. i- D6 Z' Y% F3 a7 Dthe voltage is equal to the square root of the factor for multiplying the power input. |
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