Watch An Electro-Permanent Magnet In Action

Electro-permanent magnets (EPMs) are permanent magnets that can be electrically switched on or off using a short electromagnetic pulse, without requiring continuous power to maintain their state. Inside an EPM, a permanent magnet is paired with a semi-hard magnet and an electromagnetic coil. Flipping the polarity of the semi-hard magnet causes the two magnets to cancel each other out, turning the EPM 'off'. Dave Jones of EEVblog demonstrates a Zubax FluxGrip EPM designed for drone and robotic applications, capable of holding up to 25 kg. For those seeking a cheaper alternative, a switchable magnet design using a paired electromagnet to momentarily cancel a permanent magnet is also mentioned.