Electro-permanent Magnets 101
What are they?
Electro-permanent magnet (EPM) is a type of magnet that combines both electromagnets and permanent magnets to function. It leverages the benefits of these two types of magnets to create a system that can be controlled—i.e., switched on and off—using an electrical current, but does not continuously require power to maintain its magnetic state.
Here's how they work
1. Activation: An electric pulse is applied, which rearranges the magnetization of the system, causing it to produce a strong magnetic field. After this pulse, the magnet becomes “permanently” magnetic, similar to a permanent magnet.
2. Deactivation: Another electric pulse, often in the opposite direction, is applied. This rearranges the magnetization again, this time nullifying the magnetic field, turning the magnet “off.”
Advantages
1. Safety: EPMs retain their magnetic state even in the event of a power loss, making them particularly safe for lifting applications where dropping a load could be disastrous.
2. Energy Efficiency: After activation, no continuous power is required to maintain the magnetic state, unlike conventional electromagnets.
3. Control: The ability to switch the magnet on and off provides control over its operation.
Applications
Electro-permanent magnets are widely used in various industrial applications:
– Lifting Magnets: For lifting heavy metallic objects.
– Magnetic Chucks: Used in metalworking machines to hold workpieces.
– Robotic Systems: For pick-and-place actions.
– Magnetic Clamps: For holding pieces during welding or assembly.
Electro-permanent magnets offer the best of both worlds, providing the strength and reliability of a permanent magnet and the controllability of an electromagnet.
