Electro magnets have been used in industrial lifting applications for over 100 years and their working principle as well as their two main generic components are well known, these being a ferrous core fitted with pole shoes (polarities) at its extremity and an electro conductor winding (typically made of aluminum or copper) surrounding part of the core. The passage of direct current through the winding results in the magnet being energized.
The lifting force of an electro magnet is determined by three factors which are:
Once an electro magnet is designed and built, the first two elements (size and turns) are set while the third one (current) can vary based on direct voltage (Vdc) setting and winding temperature that impacts the electrical resistance (R) of the winding conductor (Vdc= R x Idc). Electro magnets generate heat (Joule effect) when energized and the hotter the magnet winding, the more the current decreases.
The four elements that impact the internal temperature of an electro magnets are:
The first two elements (material temperature and duty cycle) are specific to every application and situation while current density and the type of magnet winding conductor are decided by magnet designer.
In order to optimize heat dissipation, magnet force and magnet life time, the SGM electro magnets are designed with very conservative electrical density for their winding and, as a standard, their windings are of anodized aluminum strip.