The Developing Of Automatic Test Machine For Positive Temperature Coefficient Heating Elements And Its Appliances

Positive Temperature Coefficient(PTC) Heating Elements is a neoteric sort of electronicelement for heating, which resistance nonlinearly changes with input voltage growth.According to Household and Similar Electrical Appliances–Safety–Part1: Generalrequirements (IEC60335-1:2010), human duty work and manual operation are fully requiredfor typical testing method, which is a waste of time and manpower, unsafe for engineer atwork, inaccurate on testing results.It is the main object of this paper to develop of automatic test machine for PTC heatingelements and its appliances, which should be fully meet the requirements in safety standardsof household appliance, IEC60335and GB4706. This paper analyzed PTC heating element inPositive Temperature Coefficient, the Curie temperature, Positive Temperature CoefficientThermistors and its operating principles, and PTC heating element working operatingcharacteristics. To determing the function of test machine, insure its operation fully meet therequirements in safety standards, this paper analyzed the requirements in safety standards ofhousehold appliance.To fullfill the requirement for the test machine, this paper analyzed the core functionalparts, the controlling system module and input-output module. Base on theoretical analysis,this paper developed and designed an automatic test machine for PTC heating elements andits appliances, including system design, circuit design, program design, and systemimplementation.To determine the stability and reliability of test machine, this paper carried out differentlevels of stringency verification test, including stability verification, verification test(normaloperation test) and proficiency testing. The tests we carried out indecated that the test machinewas stable, reliable and fullfill the requirements in safety standards.