Frameless Motors

Frameless motors as the name suggests, are motors which do not have a frame.  The stator and the rotor are delivered separately and are assembled to the load.  Thus, the motor does not have bearings.  The rotor is directly coupled to the load while the stator is coupled to the frame of the machine.  These motors are custom designed to meet the speed requirement.

Thus this arrangement eliminates the need for the coupling.  This increases the stiffness of the power train of the machine.  It also eliminates torsional application.  The size of the motor is also considerably reduced to around one seventh. This reduced weight for a given power output reduces inertial in the machine and enables quick movements and direction reversals.  

A hand tool with Frameless Motor
Frameless motors are widely used in Hand tools, Medical devices, in satellite technology and in semiconductor equipment.