Sådan afgøres, om en varmelegeme lækker elektricitet

I. Indledende vurdering (hurtig fejlfinding uden adskillelse) Elektriske abnormiteter: Ved opstart af varmeapparatet udløses lækagebeskyttelsesafbryderen tilfældigt; termostaten rapporterer ofte overstrømsfejl; dette er ledsaget af uregelmæssige udsving i termoelementets temperaturaflæsninger, hvilket kraftigt tyder på en lækagefejl. Visuel inspektion: Observer varmelegemet for tegn på lokal forbrænding, udbuling eller smeltning/beskadigelse af isoleringslaget. Tjek for sorte pletter, der indikerer fugtoxidation eller krybning ved ledningsterminalerne. II. Præcis offline statisk isoleringsvurdering: Afbryd helt varmeapparatets 220V strømforsyning. Afbryd alle ledninger mellem varmeren og termostaten for at forhindre højspændingstest i at beskadige termostatens interne kredsløb. Brug et kalibreret digitalt megohmmeter med et 500V-område. Tilslut L-terminalen til en hvilken som helst strømindgangsledning på varmelegemet, og E-terminalen til varmelegemets metalhus/varmerørhus. Efter kontinuerlig test i 1 minut aflæses isolationsmodstandsværdien: Større end eller lig med 5MΩ indikerer ingen lækage; 0,5MΩ~5MΩ er en advarsel om isolationsforringelse;<0.5MΩ directly indicates a clear leakage in the heater. Complete static insulation tests for all heaters channel by channel, marking leakage circuits with abnormal insulation resistance. III. Accurate Determination of Dynamic Leakage Under Live Conditions Restore normal power supply to the heaters, raise the temperature of the hot runner to the rated operating temperature of 320℃, and maintain this temperature for 2 hours to allow the system to enter stable operating conditions. Use a high-precision AC millivoltmeter, connecting one end to the reliable grounding point of the equipment, and the other end sequentially contacting the heater casing, the runner body, and the thermocouple shielding layer. If an AC voltage ≥5V is detected, it can be determined that a dynamic leakage exists in this circuit. The higher the voltage value, the greater the leakage current and the higher the risk of leakage. Simultaneously observe the temperature controller data. If the sensor reading changes synchronously when the leakage voltage appears, it can be confirmed that the leakage has caused crosstalk to the signal link. IV. Segmented Leakage Point Determination First, separately remove the heating core body to test its insulation resistance, eliminating leakage interference from external heating cables and aviation connectors. If the heating core body insulation is合格 (qualified), then test the insulation performance of the heating cables and connectors segment by segment to locate leakage points caused by damaged cable insulation or moisture-induced oxidation of connectors. Disassemble the heater to confirm its internal condition, checking for leakage paths caused by moisture in the magnesium oxide insulation layer, heating wire touching the shell, or cracked ceramic lining.