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5.12 For heating appliances and combined appliances, when it is specified that the
f$ [ F8 I5 |( T1 N1 kappliance has to operate at a power input multiplied by a factor, this applies only to heating2 N: O, b: k1 A6 D1 m3 \* M w
elements without appreciable positive temperature coefficient of resistance.
2 m2 {6 b N- F8 j3 f0 AFor heating elements with appreciable positive temperature coefficient of resistance, other than& Z9 p$ E3 Y4 }) o
PTC heating elements, the supply voltage is determined by supplying the appliance at rated B: t2 M+ f W- h1 H1 D9 _
voltage until the heating element reaches its operating temperature. The supply voltage is then
1 c6 R7 V* x: I3 ~: _' _Copyright International Electrotechnical Commission# i( g8 i5 t2 H
rapidly increased to the value necessary to give the power input required for the relevant test,
: n1 ^" r6 ?7 V- }! e2 X1 }this value of the supply voltage being maintained throughout the test.9 z' c4 ]9 d1 J0 p
NOTE In general, the temperature coefficient is considered to be appreciable if, at rated voltage, the power input
+ h, m" Q! J6 B7 N* p5 c# Pof the appliance in cold condition differs by more than 25 % from the power input at operating temperature.
* d! j- A8 u! n( N% N( f0 b+ V: Q5.13 The tests for appliances with PTC heating elements and for heating appliances and* ?0 \5 S/ M% U
combined appliances where the heating elements are supplied via a switch mode power4 r1 @8 q) o9 V, v5 U
supply are carried out at a voltage corresponding to the specified power input.
* d3 _' P3 K6 H1 L( s$ F" Y# Y2 IWhen a power input greater than the rated power input is specified, the factor for multiplying/ g N! R$ Y: E$ a O b$ [+ D
the voltage is equal to the square root of the factor for multiplying the power input. |
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发表于 2012-10-14 22:14
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