Kako utvrditi curi li grijalica struja

I. Početna procjena (brzo rješavanje problema bez rastavljanja) Električne abnormalnosti: Nakon pokretanja grijača, prekidač za zaštitu od curenja nasumično se aktivira; termostat često javlja prekostrujne greške; ovo je popraćeno nestalnim fluktuacijama u očitanjima temperature termopara, što snažno ukazuje na grešku curenja. Vizualni pregled: Promatrajte znakove lokalnog gorenja, ispupčenja ili topljenja/oštećenja izolacijskog sloja na kućištu grijača. Provjerite crne mrlje koje ukazuju na oksidaciju vlage ili puzanje na stezaljkama ožičenja. II. Precizna izvanmrežna procjena statičke izolacije: potpuno isključite napajanje grijača od 220 V. Odspojite sve žice između grijača i termostata kako biste spriječili da ispitivanje visokog napona ošteti unutarnji krug termostata. Koristite kalibrirani digitalni megohmmetar s rasponom od 500 V. Spojite priključak L na bilo koji vod za napajanje grijača, a priključak E na metalno kućište/kućište vrućeg kanala grijača. Nakon neprekidnog ispitivanja od 1 minute, očitajte vrijednost izolacijskog otpora: veći ili jednak 5 MΩ označava da nema curenja; 0,5MΩ~5MΩ je upozorenje na degradaciju izolacije;<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.