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All About Industrial Frameless Motors

There has been research and development conducted by companies like never before, among others in the field of the frameless motor. Companies that understand the importance of innovation and creating innovative products are able to compete in the competitive world of today. In order to create products, innovative solutions are required.

Now, even though the standardized housed motors are able to provide a wide range of options for an appealing price, there are still some constraints that they introduce for the manufacturer. Companies seeking maximum performance for realizing their vision need an industrial frameless motor, as it offers a greater degree of freedom in design.


What are Frameless Motors?

Frameless motors are often sold as separate stators and rotors that enable them to be directly integrated into the equipment. Unlike the housed motors, the frameless motors are known to be considerably more compact. While, the housed motor would be delivered just like an assembled device, it would have a standardized frame size which is specified by NEMA (National Electric Motor Association) and IEC (International Electro-technical Commission).

Normally, housed motors are shafted and have a hollow-bore configuration. However, both types have bearings as selected by the manufacturer. Feedback for position control is also required by housed motors.

Now that one knows what a housed motor is, they can better understand a frameless motor. As the name already suggests, the frameless motor is an un-housed motor. It would not be delivered as a completely assembled device, but it would rather be delivered as a separate stator and rotor. It is due to this reason that the frameless motor can directly be integrated into the mechanical structure of a machine.


Why Use Frameless Motors?

No couplings, shafts or gearboxes are required by these motors, as these would introduce machine resonances and compliance. Therefore, the frameless motor is able to deliver the load to the desired position much more precisely and with less settling time or overshoot.

The frameless motor is also known as kit motors or built-in motors, the devices do not include sensors, encoders, shafts, or bearings, but, mounting hardware may be included. The equipment builder would need to add all of those elements.


Greater Control over the Performance and Parameters

The main reason behind the popularity of industrial frameless motors is the fact that they provide greater control over the performance and parameters of the system and the motor as a whole.

Frameless motors are slightly more malleable which allows for better design for the application. There is more discussion about the custom diameter and length when it comes to un-housed motors. Their precise design match leads to much higher dynamics for the machine to achieve.

Minimize Size and Weight

Frameless motors are the ideal choice when weight and size have to be minimized. It is also perfect when the application requires the highest possible performance. One can install them directly into a robotic joint for much more compact geometry. Portable power tools and even medical devices use the. They can even be designed for delivering a very high torque, especially for low speeds.

Improved Technology

The improved technology of frameless motors allows more time to be spent for focusing on the aspects of the design which contribute the most to application. Complete design freedom can be achieved with a frameless motor.

Linear Models

Now, even though the term frameless motor is mostly associated with the rotary design, there are some linear versions that are available as well. In fact, the linear motors are shipped as a separate magnet and forcer track.


Available in Different Sizes

The frameless motors are available in different sizes. Size and high power density is one of the greatest factors behind the popularity of frameless motors. Direct drive brushless motors can be developed as a result of this. Although, they may be small in size, they certainly have a high power-to weight-ratio. It is a safe kit and has a low voltage of 48V brushless motor. It is due to this reason that they can be used for a wide range of purposes such as the following.

  • Pumps, compressors and others
  • Moving elements
  • Industrial equipment
  • Robotics projects
  • Medicine


The Benefits of Frameless Motors

  • The multi-axis gimbals ensure effective results. They handle heavy loads, yet remain lightweight and compact.
  • Can be used for defense and aerospace applications for the satellite communications and beam steering.
  • Additional mass of oversized motors can be handled.
  • Cost-effective
  • They deliver the same force as housed motors, yet they remain considerably lighter.
  • Waste of fuel can be eliminated.
  • Industrial uses such as indexing tables can truly benefit from the reduced weight.
  • Lower inertia due to lower mass which improves the overall dynamic performance.
  • Stiffer control loops can be used. This allows the indexing tables to make faster moves with there being less settling time.
  • The need for belts and gearboxes is also reduced.
  • Sources of mechanical error, points of failure and maintenance would significantly decrease.
  • They can provide accurate and very tight speed, and better position control for much wider applications that range from centrifuges to machine tools.
  • Clear on-axis can be realized through the motors.
  • They do not suffer from any backlash, which makes them perfect for any type of repetitive motion. It includes pick-and-place operations and semi-conductor wafer inspection.


Thermal Management

In addition to the above, frameless motors allow for much more sophisticated approaches to be used for thermal management. The frameless brushless motors allow for the thermally conductive material to create better and more efficient thermal paths.  The thing about un-housed motors is that the bearings are selected to give the exact performance required and fit the application.

However, for a frameless motor, proper air gap is not guaranteed unlike a housed motor, which is why the responsibility lies with the equipment builder.



Industrial frameless motors are the way to go when it comes to design and innovation. They offer many advantages and can be used for various reasons which is why it is important to give them a try.

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