Electromagnets for electromechanical systems

When a ferromagnetic part is subjected to a magnetic field, it tends to move, reducing the length of the magnetic circuit. This reduces the circuit's reluctance. This principle underlies the operation of electromechanical converters, and electromagnets are no exception. An electromagnet is schematically made up of two pieces of ferromagnetic material, one fixed and the other mobile (the armature), and a coil creating the magnetic field (figure 1 ).

The fixed part comprises a winding through which a direct, alternating or transient current flows. This current generates a magnetic field in the core, armature and air gap. The interaction of the field with the ferromagnetic material making up the armature generates a magnetic force that tends to displace the armature.

The electromagnet is the basic element of electromechanical systems. They are widely used as carrier electromagnets, control electromagnets, etc. The main advantages of electromagnets over competing technologies (hydraulics, pneumatics) are their low production cost, low response time and the absence of environmental pollution during operation. Energy-saving considerations should also be mentioned. The electromagnet, with its closed magnetic circuit (bonded armature), consumes, in certain configurations, extremely low power while producing high force. This is particularly important in fire safety applications, for example.

Choosing the right electromagnet for the right function, as described in the specifications, requires the use of reliable design and simulation models for electromagnet operation.