Both permanent magnets and electromagnets can be made to produce different forms of magnetic field. When choosing a magnetic circuit, the first thing to consider is what you need a magnet to do. Permanent magnets prevail in situations where electricity is inconvenient, power cuts are frequent, or where there is no need to adjust the magnetic force. Electromagnets are useful for purposes that require changes in magnetic force or require remote control. Magnets can only be used in the way they were originally intended, and the wrong type of magnet used for a particular purpose can be extremely dangerous or even fatal.
A permanent magnet
Many machining operations are performed on heavy block materials, and these USES require permanent magnets. Many machine shop users believe that the greatest advantage of these magnets is that no electrical connection is required.
Permanent magnets feature 330 to 10,000 pounds of lift capacity and can be turned on or off by simply turning a handle. Magnets are generally fitted with safety locks to ensure that they do not accidentally break during lifting. The magnet assembly can be used for heavier and longer loads than a single magnet can handle.
Also, in many cases the parts to be machined are very thin (0.25 inch or more) and have to be extracted from a pile of similar parts. Permanent magnets are not suitable for lifting just one piece at a time from a pile of parts. Permanent magnets, although extremely reliable when used correctly, do not change the size of their force. In this respect, the electromagnet enables the operator to control the strength of the magnetic field through a variable voltage control device and to select one of the stacked parts. Self-contained electromagnets are the most cost-effective magnets by lift capacity, which can be extended to 10,500 pounds.
Battery-powered magnets are useful because they use self-contained colloidal batteries to increase lift capacity and can handle flat, round and component shaped products. Battery-powered magnets can perform the lifting action repeatedly, providing considerable lift capability without an external power source.
