After installing the new coil, it is recommended to use an infrared thermometer during the first heating stage to compare the deviation between the coil surface and the set temperature of the barrel. If the deviation continuously exceeds ±15°C, check the contact gap between the coil and the barrel. The DJR-860 model adopts a spring clamp structure with an inner diameter tolerance controlled within ±0.5 mm. During installation, confirm that the clamps are fully engaged to avoid uneven heat transfer caused by local lifting.
When local dark spots or cold zones appear on the coil surface, and the cold resistance measured with a multimeter rises by more than 8% compared with the initial value, it usually indicates intensified oxidation of the resistance wire. The DJR-860 model uses nickel-chromium alloy wire, with a design power density controlled within 3.5 W/cm². Combined with the mica insulation layer, it can maintain relatively stable resistance characteristics under continuous operating conditions. It is recommended to record the cold resistance once a quarter and establish a trend file.
Terminal heating is mostly caused by loose crimping or thickened oxide layers. The DJR-860 model is equipped with ceramic terminals in the junction box and supports 2.5 mm² wires. During maintenance, after powering off, check the screw torque, remove the oxide layer, and replace the terminals if necessary. If the terminal temperature continuously exceeds the ambient temperature by 40 K, check whether the supply voltage exceeds the ±10% range of the rated value of 220 V.
After long-term shutdown, the insulation resistance may decrease due to moisture absorption. Before startup, measure the cold insulation resistance with a 500 V megohmmeter; it should be no less than 20 MΩ. The lead wires of the DJR-860 model use high-temperature-resistant fiberglass sleeves. Check that the sleeves are not damaged and have no carbonization marks. Before energizing, run at no load at 50% of the rated voltage for 30 minutes to drive off moisture, then gradually increase to the operating voltage.
Rated voltage is selectable between 220 V and 380 V, power range is 0.8 kW to 3.5 kW, and maximum operating temperature is 450°C. The coil body uses a stainless steel shell, with a built-in mica insulation frame and nickel-chromium resistance wire. It is suitable for the heating sections of injection molding machine and extruder barrels, especially for maintenance scenarios requiring frequent disassembly and assembly. When selecting a model, it is recommended to calculate the power per unit area based on the barrel diameter and heat dissipation conditions, and avoid blindly increasing the power.
