Corrosion and Wear Prevention

• One little-known use for magnets is that of attracting ferrous contaminants in systems such as water heaters and engines. Water heaters can take in metallic calcium particles through the freshwater intake pipe, and the resultant buildup can clog or damage internal components. A magnet on the freshwater intake pipe will catch and hold these particles, preventing them from collecting within the heater. A ceramic magnet placed in a vehicle's oil pan will attract steel shavings that collect in oil from grinding pistons. Preventing these shavings from remaining mixed with the motor oil keeps them from rubbing against engine components and causing internal damage.
  
  

Magnetic Media

• Audio, video and data storage media such as tape cassettes, computer disks and digital audio tapes utilize a coating of iron material that stores tiny magnetic fields in a pattern. These fields represent stored information, which is then converted to data or into an audio or video signal when the medium is read.
  
  

Conveying, Sorting and Separating

• Magnets are often used in recycling and other metal sorting applications to separate ferrous and non-ferrous materials. For example, magnets may be used to separate steel cans from aluminum cans in automated aluminum recycling facilities. Other magnets may be used to separate impure metals from high volume industrial flow, in automated conveyors and separators, as well as magnetic grates and plates. Food vending machines use magnets to separate coins from other objects. Magnets are also used to recover magnetic and ferrous materials from the depths of the ocean.
  
  

Stepper Motors

• A stepper motor consists of a rotating shaft that spins due to manipulation of the magnetic fields around it. The shaft is either a permanent magnet or has such a magnet as one of its components. The manipulation of electromagnets located in the stator, which surrounds the shaft, causes the shaft to spin. As one electromagnet is turned on, the shaft spins so that its poles align with the opposite poles of the electromagnet in question. As each electromagnet around the shaft is turned on and off in sequence, this causes the shaft to complete one full rotation. Stepper motors typically contain three to four electromagnets, although one less common design incorporates only two electromagnets within the stator.