For medical applications, micro brushless motor is 4 mm in diameter
The EC 4 brushless DC motor is maxon motor’s ultra-compact offering; the smallest micromotor made by the Swiss manufacturer, the EC 4 is only four millimeters in diameter. It is available in two lengths, with power ratings of 0.5 and 1W. Equipped with an ironless maxon winding, maxon cites robust design, high power density, and energy efficiency.
Combined with the GP 4 planetary gearhead, the EC 4 becomes a compact drive for use in micropumps, analytic and diagnostic devices, and laboratory robots. Precise and reliable, it can adjust lenses, dispense fluids, or position sensing devices. All units meet the ISO 13485 medical standard, which makes this maxon micro drive a suitable choice for applications in medical technology.
maxon; www.maxonmotor.com