In the case of a DC electromagnet, reducing the temperature of the energized coil requires converting the energy it consumes in the resistor into heat, reducing the temperature in the conductor.
If it is an AC electromagnet, its coil temperature rises in addition to its own resistance, but also because the temperature of the core rises, if there is an induced current in the core of the AC magnetic field, there will be part of it. When the electrical energy is lost, the temperature of the iron core will rise accordingly, and the induction cooker uses this principle to increase the temperature. Since the coil is wound around the iron core, its heat is reduced after it is transmitted to the coil. In order to amplify the induced current loss in the iron core, the AC electromagnet is similar to the transformer, so that the mutual component can be used. The insulating silicon sheet is used as the iron core, and its loss is amplified, and the temperature of the coil can be lowered.
However, if the electromagnet is always energized and its temperature only rises to about forty degrees, this phenomenon is normal, don't worry.