A motor the size of a pencil tip

For applications that require a powerful motor unit to be packed into a very tight space, the new RE8 miniature motor from Maxon Motors is 8mm in diameter, is 16mm long, weighs less than 4g and is capable of achieving a nominal power rating of 0.5W. Its ceramic shaft is as thin as a pencil lead and rotates in two sleeve bearings. And because it's made of ceramic rather than steel, it has better electrical insulating properties enabling a more compact commutator design. Bearing wear is also minimal in comparison with that of steel components. The motors use brushes made of precious metal that ensures constant and low- contact resistance with the commutator – even after a prolonged standstill. And the 'heart' of the motor is the worldwide patented ironless rotor, the System Maxon, which benefits from a unique, lightweight coil winding. This results in a motor with unusually low mass inertia and very fast acceleration. There is no magnetic detent at all, and minimal electromagnetic interference. As far as efficiency is concerned, according to Maxon, the motor's neodymium permanent magnet, combined with its ironless winding makes the motor more efficient than any competing brands currently on the market. The Re 8 motors can be fitted with planetary gearheads and encoders if necessary. "The units are also ideally suited to life-preserving medical applications such as body-worn insulin pumps and perfect for 'light chopping' in a wide variety of laser-based equipment," says Keith Ellenden, CEO of Maxon Motors UK.