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5.12 For heating appliances and combined appliances, when it is specified that the- J( R& g3 D( }' l/ _. x
appliance has to operate at a power input multiplied by a factor, this applies only to heating) Q2 \1 k, T0 L
elements without appreciable positive temperature coefficient of resistance.
$ B8 O, ~. i$ O# @5 uFor heating elements with appreciable positive temperature coefficient of resistance, other than
' H; i( m1 }0 V4 c: z8 X9 ^9 ZPTC heating elements, the supply voltage is determined by supplying the appliance at rated: j8 D: @1 Z7 Y' p
voltage until the heating element reaches its operating temperature. The supply voltage is then
5 l1 R/ H1 v( w7 b$ Y& pCopyright International Electrotechnical Commission
& N% ]0 x, L3 F/ O0 p- S# W M. Zrapidly increased to the value necessary to give the power input required for the relevant test,
- w& ?+ N, {0 S! |8 w/ }3 w2 b& R3 Pthis value of the supply voltage being maintained throughout the test.
r9 `; |! b4 h. j' Q) \1 zNOTE In general, the temperature coefficient is considered to be appreciable if, at rated voltage, the power input/ G. r" m8 g$ R' y
of the appliance in cold condition differs by more than 25 % from the power input at operating temperature." P0 [* _- r! v7 m& ~
5.13 The tests for appliances with PTC heating elements and for heating appliances and5 R' C, e6 h/ Z
combined appliances where the heating elements are supplied via a switch mode power& J M* q+ J5 K
supply are carried out at a voltage corresponding to the specified power input.0 b& o2 z4 {' y2 Z4 F
When a power input greater than the rated power input is specified, the factor for multiplying
$ i* Y- a( v9 A1 ]the voltage is equal to the square root of the factor for multiplying the power input. |
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