JB/T 12719-2016 Test method of accelerated life of daily-use metallic tube electric heating elements
1 Scope
This standard specifies the test method of accelerated life of daily-use metallic tube electric heating elements (hereinafter referred to as “elements”).
This document is applicable to the accelerated life test of daily-use metallic tube electric heating elements installed in household electrical appliances, with a rated voltage not exceeding 480 V and single-tube rated power not exceeding 6 kW.
2 Normative references
The following documents contain requirements which, through reference in this text, constitute provisions of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB 4706.1-2005 Household and similar electrical appliances - Safety - Part 1: General requirements
GB 14536.8-2010 Automatic electrical controls for household and similar use - Particular requirements for timers and time switches
JB/T 4088-2012 Daily-use metallic tube electric heating elements
3 Terms and definitions
For the purposes of this document, the terms and definitions given in JB/T 4088-2012 and the following apply.
3.1
daily-use metallic tube electric heating elements
elements used for heating, using metallic tube as the case and alloy heating wires as the heater, with the space between them filled with dense magnesium oxide powder or similar insulating material as the insulating medium, and connected to the power supply through a lead-out rod
3.2
failure mechanism
intrinsic causes such as physical and chemical changes that cause failure
3.3
failure mode
manifestation of an observable or measurable failure phenomenon occurring in an element
3.4
failure factor
external causes or conditions leading to failure
3.5
testing stress
input factors that directly act on the elements during the test
3.6
predefined working condition
rated usage conditions and requirements of the elements as specified by the manufacturer
Foreword i 1 Scope 2 Normative references 3 Terms and definitions 4 Test principle 4.1 Failure mechanism and failure mode 4.2 Failure factors 5 Classification and key technical parameters 5.1 Classification 5.2 Main technical parameters 6 Test device and environmental requirements 6.1 Test device 6.2 Test environment 7 Test requirements 7.1 General requirements 7.2 Elements classified under 5.1.1 7.3 Elements classified under 5.1.2 7.4 Elements classified under 5.1.3 7.5 Elements for other heating purposes 7.6 Situations allowing for coverage test 8 Test methods and evaluation 8.1 General requirements 8.2 Dry heating cycle test 8.3 Dry heating and fast cooling test 8.4 Voltage step-up test 8.5 Overload cycle test 8.6 Fast on-off cycle overload test 8.7 Leakage current measurement at operating temperature 8.8 Electric strength test at operating temperature Annex A (Informative) Limit operating temperatures of materials commonly used for the elements Bibliography Table 1 Power applied vs. rated surface load Table 2 Electric strength test at operating temperature Table A.1 Limit operating temperatures of materials commonly used for the elements
