Causes of Short Circuit and Installation Methods of Cartridge Heaters

Cartridge heaters are widely used in mold heating and other industrial electric heating equipment. However, low-quality unmodified magnesium oxide powder tends to absorb moisture in the air, resulting in a short circuit of the electric heating tube. Nevertheless, the short circuit between the two lead wires of cartridge heaters is not always caused by this factor. The main causes are summarized as follows:

Ferric-chromium-aluminum alloy adopted for lead wires features excessive resistivity, which raises the temperature of the lead wires and triggers faults. Exposed to the air, the heating zone shifts toward the terminals of the lead wires.

Mismatched rated voltage of the two lead wires and excessive operating temperature lead to short circuits.

Defects in module drilling technology. The bell-mouth shape of the mold hole opening impairs heat conduction and causes air breakdown.

Loose powder at the tube opening where lead wires extend out, and an excessively small distance between the two holes for lead wire penetration.

Low-quality sealing silicone is too close to the first circle of threads at the root of the lead wires.

The installation methods for cartridge heaters are as follows:

Standard cartridge heaters require no special fixation. They can be directly inserted into heating channels for operation or fixed and heated with brackets.

Baffle-type cartridge heaters generally need a pre-drilled hole on the mounting surface for tube penetration, with the baffle serving for fixing and supporting. This type of heater can be installed horizontally or vertically. When installed transversely, the baffle mainly protects the lead wires.

Threaded cartridge heaters are installed by tapping threaded holes at the mounting position, and the heater can be fastened in place via threads. Threaded connection brings multiple advantages: simple installation and replacement, excellent sealing performance and high structural stability.