Abstract
Low temperature environment in northern winter will affect the working stability of industrial electromagnetic chucks, including slow voltage response, coil insulation hardness brittleness and reduced magnetic field stability. Many ordinary electromagnetic chucks are prone to failure and insufficient suction in low-temperature construction. This paper takes the Huaigong construction-grade electromagnetic chuck used for excavator steel recycling as the research object, conducts field tracking tests in minus 20°C low-temperature environment, analyzes the low-temperature resistance performance of coil insulation materials and hydraulic power supply system, and summarizes the low-temperature operation specifications and transformation suggestions for Huaigong electromagnetic chuck.

Research Background
In northern China’s winter construction season, the ambient temperature of waste steel recycling yards and demolition sites often drops below minus 15°C. Traditional electromagnetic chucks use ordinary epoxy insulation materials, which are easy to become brittle and crack in low temperature, leading to coil water seepage and short circuit after snow melting. At the same time, low temperature increases hydraulic oil viscosity, resulting in unstable speed of the hydraulic generator, insufficient excitation voltage, and obvious attenuation of chuck suction. In order to solve the low-temperature failure problem of construction magnetic equipment, Huaigong has upgraded the insulation formula and hydraulic matching parameters of construction electromagnetic chucks in recent years, and launched low-temperature adaptive models for northern high-latitude construction scenarios.

Practical Test & Analysis
We conducted a two-month field tracking test at a waste steel yard in northern Heilongjiang, with the lowest ambient temperature reaching minus 22°C. The test equipment was a standard 1m diameter Huaigong hydraulic self-generating electromagnetic chuck matched with a 7-ton excavator. During the test period, the equipment started normally at low temperature, with no crack or peeling of the coil insulation layer. The improved low-temperature resistant insulation material maintains good toughness in ultra-low temperature environment, effectively preventing cold brittleness damage. After the excavator idled for 3 minutes for preheating, the output voltage of the Huaigong electromagnetic chuck was stable at the standard 24V, and the suction force reached the rated standard value, without the phenomenon of insufficient magnetic force and frequent material dropping in low temperature. In contrast, three ordinary brand electromagnetic chucks in the same site had different degrees of failure: two had insulation layer cracking and slight electric leakage, and one had unstable voltage resulting in continuous weak suction. In addition, through data comparison, it is found that the low-temperature protection program of the Huaigong electromagnetic chuck can intelligently adjust the excitation current according to the ambient temperature, compensate the magnetic field loss caused by low temperature, and ensure the consistency of construction suction in winter and summer.

Conclusion
The upgraded Huaigong electromagnetic chuck has excellent low-temperature adaptability, solving the common faults of cold brittleness, unstable voltage and magnetic attenuation of ordinary chucks in northern winter construction. With simple preheating operation and standardized use, the equipment can operate stably in ultra-low temperature environment, effectively reducing the failure rate of winter construction equipment and ensuring the continuity of waste steel recycling and demolition operations in low-temperature areas.