A magnetic force in dry-reed relays

A method for calculating the magnetic force between reeds is presented. The method is based on the premise that an energizing coil creates two magnetic bodies inside itself that are similar to two permanent magnets. The magnetic field is generated outside the bodies. Magnetic reeds can be replaced by an equivalent set of current-carrying solenoids that produce exactly the same magnetic field distribution as the bodies. The demagnetizing effects in reeds was measured and incorporated. Having found the component of the magnetic field with the same direction as the magnetic force used and the motion of the reeds, the author calculates the stored magnetic field energy in an overlapping space between the reeds. The inhomogeneity and high concentration of the magnetic field at the end of the reeds are taken into consideration. The magnetic force between the reeds depends on the change of the stored magnetic field energy during the motion of the reeds.<>