How to Choose & Use Lifting Magnets - ERIEZ - #4

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CONSTRUCTION OF LIFTING MAGNETS Did you know? All electromagnets use DC power. In applications whereAC power is preferred, a rectifier is needed to convert ACpower to DC. Accordingly, it is possible to operateelectromagnets from a DC battery source. Lifting magnets fall into two general shapeclassifications: round and rectangular.The round lifting magnet is built with a centerpole (or core) and a round outer pole concentric with the center pole. This magnet can be either permanent or electro.The round electro lifting magnet is most efficientwhen considering its face area as related to lift power. Because the outer pole is a consistent distance from the core or center pole, the result is a uniform magnetic strength over the magnet face area. Black iron pipe or steel tubing is used for outer poles of round lifting magnets, and hot rolled steel round bar stock is used for the center core of round electro magnets.The rectangular lifting magnet is built witheither of two basic magnetic circuits, the two- pole or three-pole circuit, and it also can be permanent or electro.Pole plate and core material will be hot rolledsteel or low carbon steel. For the plates of rectangular lift magnets hot rolled steel plate is welded and joined into the required box shape. Using these stock materials, there is no limita- tion to lift magnet geometry, but round and rectangular lift magnets will usually prove adaptable to almost any lifting application.
Outer Pole CoilCore Permanent Magnet Permanent MagnetPERMANENT PermanentMagnetNNSNS age ELECTRO CoreCoilNNS CoreCoilNS WEIGHT, SHAPE AND AREA OF LOAD 4 Weight, shape and contact area must be considered at the very beginning inlifting magnet selection. The contact area of the load controls the required magnet number and size almost as much as the weight of the load. If a given load offers a relatively small surface area to the magnet face, then a magnet has to be selected that has a magnetic field that will “penetrate” the load thickness, so that holding power is sufficient for the load involved.