The design objective of creating a more compact and powerful electromagnetic overband magnet recently led the Bunting engineering team to develop the new ElectroMax-Plus. The magnetic field of the light and compact ElectroMax-Plus Bunting says is both deep and strong, enabling excellent separation performance at higher suspension heights. The new ElectroMax-Plus extends Bunting’s comprehensive range of overband and suspension magnets. In additional to standard sizes, Bunting also designs and manufacturers bespoke models which are application specific.
Electromagnetic overband magnets use an oil-cooled or air-cooled wire coil to generate a deep and strong magnetic field. The electromagnetic force radiates from a coil wound around a steel core and mounted inside a steel box with a thick steel back-bar. This focuses the magnetic field in one direction: down towards the conveyed material. In operation in mining, an overband magnet, suspended over conveyors, screens, and vibratory feeders, lifts and removes ferrous metals such as rebar or excavator teeth.
Overband magnets are a common feature on many mining mobile screens and crushers. In such applications, minimising weight and size is crucial and, subsequently, operators use standard ceramic ferrite or, less frequently, neodymium rare earth permanent overband magnets rather than electromagnets. Neodymium permanent overband magnets produce a strong but shallow magnetic force and often experience problems with belt and motor damage due to large ferrous metal clamping against the magnet block.
In addition, simply turning off the electromagnet releases any extremely large entrapped tramp ferrous metal. The shape and nature of this magnetic field means there is less wear to the self-cleaning belt mechanism (e.g. belt, motor gearbox, and bearings).
The new ElectroMax-Plus operates at a 600 mm suspension height (the distance between the conveyor belt and the face of the overband magnet), up from 450 mm on a standard ElectroMax. At a suspension height of 500 mm, the ElectroMax-Plus is over 105% stronger (in terms of Force Index) that the equivalent ElectroMax. This additional magnetic force removes small tramp ferrous metal commonly missed by permanent overband magnets. The company says the latest ElectroMax-Plus provides companies in the recycling, quarrying, and mining sectors with a powerful and compact solution for separating tramp and secondary ferrous metal from conveyors.
Adrian Coleman, General Manager of Bunting’s Redditch operation says companies supplying mobile equipment are requesting stronger and lighter overband magnets. “The new ElectroMax-Plus provides a real alternative to neodymium rare earth overband magnets. There is the requested additional magnetic strength, without the operating problems as experienced with some neodymium rare earth overband magnets.”
Bunting is one of the world’s leading designers and manufacturers of magnetic separators, eddy current separators and electrostatic separators for the recycling and waste industries. The Bunting European manufacturing and product testing facilities are in Redditch, just outside Birmingham, and Berkhamsted, both in the UK.