小米 发表于 2012-9-9 15:07

DSH 554 Power input of appliances with PTC heating elements


http://decisions.iecee.org/icons/ecblank.gif DSH 554

Power input of appliances with PTC heating elements
10.1
60335-1(ed.3) & 60335-1(ed.4)


Question:
Over what representative period is the power input measured for an appliance incorporating a PTC heating element?
Rationale:
If the power input varies throughout the operating cycle, the power input is determined as the mean value of the power input occurring during a representative period.
For appliances with a PTC heating element, the initial power input is very high and this reduces as the PTC heating element heats up.
Decision:
The representative period cannot be defined in Part 1. It depends on the appliance. The input power should be measured when steady conditions are reached or at the end of the duration specified in clause 11.7 of the Part 2s, whichever shorter.


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