Lift magnets are heavy duty pieces of equipment that are essential for ensuring product and process safety. They are most often seen in the construction and recycling industries, where they are typically used to transport high volumes of metal. Metal recycling plants, shipyards, bridge construction and demolition sites are all places where these devices are common. While these tools may appear simple at first, they operate using extremely complicated scientific principles.
The most powerful lift magnets are fitted with an electromagnet. However, because these attractors do not work when power is cut off, most come with a permanent magnet backup. This ensures that there is minimal risk of injury in the event of a power failure. Permanent attractors are made from rare earth metals, and come in two varieties – samarium cobalt and neodymium. Electrically charged attractors are typically preferred for industrial projects because their field and strength can be manipulated by changing power flow to the device.
Electrically charged attractors are made of coiled wiring wrapped around an iron core. When electricity is channeled through the wiring, it naturally creates a field that draws in ferrous metals. By looping several coils together densely, the strength of this field can be multiplied by many times. On its own, the iron core only produces several weak attractive fields, known as domains. This is because the natural state of the metal contains a disorganized mass of domains that point in random directions. This is chemically inherent to the iron core. Once a strong energy field passes over the metal, though, these domains are aligned in a uniform direction – parallel to the field created by the electrical current. The iron’s field and the attractive field created by the electricity synergize with each other, greatly increasing the power of the attractive force. This, in short, is how lift magnets quickly generate powerful forces. By reducing the electrical current, the power of the device’s field can be dulled, making it much safer to operate compared to rare earth versions. During manufacturing of the device, wrapping the coils tighter or producing more of them can improve the power output. These coils are made out of highly conductive material, usually copper or aluminum. They are highly sensitive to damage or moisture, so they are plated with more durable metals like manganese. Manganese is both hardy and unaffected by the attractive field.
In the recycling industry, lift magnets are used to transport high volumes of scrap metal to processing. Iron and steel recycling processes require large quantities of scrap, and the most cost effective way to do this is with these devices. Because their power output can be alternated, these machines can target smaller or larger items to pick up.
Crane suspended lift magnets are also adept at separating nonferrous materials from ferrous metals. While passing over a mass of scrap metal, only iron and steel are picked up by the device. This helps sift through and locate iron and steel for more efficient recycling. Separation ensures that the recycled metals are as pure as possible. Depositing nonferrous materials into processors can also damage sensitive factory equipment, so separation is an essential part of the job.