source:The Drive

The high-torque capabilities that frameless motors offer completely eliminate the needs for two ac vector-quality motors that are coupled through large gearboxes. Frameless motors have started to be accepted into other machines that have space issues or mounting requirements. Due to their build, frameless motors are designed into machines to provide high-speed spindles. 

Due to the recent technological advancements, frameless motors have started to used into registration-oriented operations such as printing and paper converting. The advancements in cooling techniques, precise feedback devices, and the ever-expanding use of CAD is the reason as to why frameless motors have soared into popularity recently.

But what precisely are frameless motors? For starters, frameless motors are nothing different than induction motors, in a way that they are controlled by the same devices that are used for frame-type motors. But the area where frameless motors differ is in the mechanical department.

These types of motors are delivered as individual components. The rotor, the stator, and the feedback assembly are all installed separately and are all integral to the machine itself. With high torque ratings, which usually go from 100 lb-in to 10,000 lb-in, and speeds from 300 to 20,000 rpm, frameless motors truly are a different breed of beasts. You can find out more about frameless motors on this site.

Main Advantages of Frameless Motors

The main advantage that frameless motors give is to the design engineers because:

•    Rigid Load Coupling

The most important feature, although one that is least talked about, is the fact that frameless motors increase rigidity. The rigidity is delivered throughout the entire machine and in most cases; it produces the best product quality.  The overall machine stiffness is very important, and frameless motors make up of it in abundance. The machine stiffness is dependent on the overall cumulative stiffness of all mechanical parts from the motor rotor all the way to the load. Those mechanical parts include the belts, pulleys, gears, gearboxes, couplings, and more.

•    Creative Motor Cooling

Yet another highly important advantage to frameless motors it the numerous innovative cooling methods deployed in these types of motors. The most efficient of all methods is a type called fluid cooling. Fluid cooling enables compact motors to deliver high power and sufficient cooling throughout the entire motor. Some even achieve the most cost-effectiveness by using the same fluids from various portions of the machine to cool off the frameless motor.

•    Flexibility

On the subject of flexibility, frameless motors have a distinct advantage over other types of motors due to the conventional motor design. This design involves a rotor with an integral shaft that must be coupled with the load. However, frameless motors today can incorporate a shaftless rotor with a hollow shaft to give the entire machine the necessary freedom to configure the variety of shafting options available. 

•    Compact and Very Quiet

Possibly the biggest advantage to frameless motors is the fact that there is no pre-defined frame, shaft, or bearing structure. This allows frameless motors the necessary space to operate to the desired standards, and they are so silent that they are no more than 1/7th of the volume of conventional framed motors.