Measurement of rated power of electric heating tube test method, data source: People's Republic of China machinery industry standard JB/T2379-2016 "Metal tubular electric heating element"
6.6 Rated power measurement:
6.6.1 The rated power should be measured with a power meter or voltmeter or ammeter after the component is under sufficient heating conditions or simulated conditions, and the working temperature reaches 10min. The accuracy of the measuring instrument should not be less than 1.5 grade.
6.6.2 The operating temperature of the component shall be determined by the following methods:
Under sufficient heating conditions, the temperature measurement is carried out with a surface thermometer or thermocouple at the temperature measurement point specified in the element housing, and the average temperature measured at each temperature measurement point is the operating temperature. The temperature measurement point is taken from three points, which are located at the highest temperature point, the lowest temperature point and the middle temperature point on the heating surface of the component.
6.6.3 When multiple components are connected in series to the power supply, the power of each component shall be measured separately.
6.6.4 At the time of factory inspection, it is allowed to pass the cold DC resistance value of the measuring element and convert the power according to equation (4):
Formula: P---- power in kW
U ---- rated voltage in volts V
R0 ---- cold DC resistance in Euclave Ω
CT ---- operating temperature coefficient of heating wire
The cold DC resistance and its deviation and the temperature coefficient of the heating wire must be clearly specified in the technical documents, and the accuracy of the instrument used to measure the cold DC resistance should not be less than 1 grade
