Electromagnets 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.
The SGM Electro lifting magnets are composed of a very high magnetic permeability steel casing with sections designed with a highly safety margin for heavy duty applications.
The special bottom plate is wear – resistant manganese steel with an extra-heavy cross section. The fabricated casing has a deep welded construction by submerged arc welding. Windings are preferable manufactured with anodized aluminium strips for its electrical conductors in order to optimize volume and heat dissipation.
All elements are designed for maximum lifting performance and mechanical strength.
The result is a lifting magnet that sets new standards for performance, endurance, and reliability.
The functioning of industrial electromagnets
The lifting force of an electromagnet is determined by three factors:
- The size (and geometry) of the ferrous core (the larger, the stronger).
- The number of turns in the winding (the more, the stronger).
- The amount of direct current (measured in Amperes, Idc) passing through the winding (the more, the stronger).
Once an electromagnet is designed and built, size and turns are set, while the current can vary based on the direct voltage (Vdc) setting and winding temperature, which affects the electrical resistance (R) of the winding conductor (Vdc = R x Idc).
Electromagnets generate heat (known as the Joule effect) when energized, and the hotter the magnet winding, the more the current decreases.
SGM electromagnets are designed with very conservative electrical density for their winding
There are four elements that impact the internal temperature of an electromagnet:
- The temperature of the material to be lifted (in the case of a hot application).
- The duty cycle.
- The current density of the winding conductor.
- The type of winding conductor.
The 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 the magnet designer.
To optimize heat dissipation, magnet force, and magnet lifetime, the SGM electromagnets are designed with very conservative electrical density for their winding. Additionally, as a standard, their windings are made of anodized aluminum strips.
Electro Lifting Magnets [EM] benefits
Universality: EM can generate a very deep magnetic field making them suitable for many different applications, including situations where contact between magnet pole shoes and load or the different elements constituting the load is limited with significant spaces (air-gaps). Typical examples are ferrous scrap or bundle applications where the bundle is made of many structural pieces.
Flexibility: Easy to partialize the force of the magnet by partializing the voltage or current provided to the magnet.
Suitable for hot applications, up to 650°C (1,200°F).
Limits
Need for Battery back-up: The lifting force of an EM depends on continuous electrical feeding which, when safety is a sensitive factor, requires a battery back-up system to cover possible electrical power (main) interruptions as well as suitable protection and maintenance of the power cables to prevent possible accidental interruption.
