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Frameless Motor

The FMI series by Rozum Robotics is a lineup of compact high-torque brushless AC motors designed as frameless rotor and stator kits


FMI motors—Rozum Robotics’ own R&D products—are synchronous alternating-current frameless actuators featuring superior torque density. The brushless technology employed in the drives enables packing impressive power into a compact footprint, while minimizing friction-induced power losses and ensuring noise- and spark-free operation. With low cogging torque, FMI-series products provide smooth rotation without jerkiness.

Supplied as rotor-and-stator hollow-shaft kits, FMI engines can be encapsulated into any housing of your choice and allow versatile mounting configurations. These are direct drive solutions with no bearing, or shaft, or endbells. Integrating them into an application is almost a plug-and-run operation.

A know-how stator winding enables maintaining consistent torque delivery across the available velocity span. The inrunner configuration and rare-earth magnets contribute to enhanced efficiency. Temperature-sensing elements built into the stator coils prevent overheating.

The entire delivery process—from design to the quality control stage—is under direct supervision of our specialists. Rozum Robotics offers a 1-year warranty and guarantees continuous operation of its FMI engines for 35,000 hours minimum.

Supply Kit
  • 1x Frameless motor with a thermal meter
  • 1x Rotor ring with rare earth magnets
  • 1x User Manual
  • 1x STEP model
  • 1x Low voltage equipment and electromagnetic compatibility certificate

Available modifications

Power130 W166 W405 W
Supply voltage48 V48 V48 V
RMS current2.7 A4.2 A9 A
Rated torque200 mNm300 mNm900 mNm
Peak torque500 mNm700 mNm2600 mNm
Rated speed6000 RPM5300 RPM4300 RPM
Diameter41 mm51 mm75 mm
Length21,5 mm22 mm32 mm
Weight91g148 g455 g
Distributor Price:On RequestOn RequestOn Request


  • High torque density
    Rare-earth magnets on the rotor ring generate twice as strong a magnetic field as ferrite ones. Star winding allows maintaining stable torque delivery even at slow rotation rates.
  • Compact size and low weight
    Direct-drive FMI motors have small size but boast high power-to-weight ratio. Easy to fit into tight spaces and require no additional fittings or accessories to transmit the moving force to driven machines.
  • AC synchronous operation
    The working principle is associated with smooth rotation at low cogging, slight noise, and insignificant electromagnetic disturbances.
  • Hollow-shaft design
    Supplied as rotor-and-stator kits with no shaft, the engines are easy to assemble and mount. Allow for multiple drive mechanism configurations, depending on application specifics.
  • Brushless commutation
    Minimized power losses resulting in a higher torque-to-weight ratio and greater motor controllability. Decreased maintenance and failure rates due to fewer wearable components.
  • Integrated thermal sensor
    The stator coils in the FMI kits comprise temperature-sensing elements. The devices ensure engine cutoff at overheating, thus preventing demagnetization.
Industrial equipment
Commercial applications
Printing / scanning

Frameless motors offer such advantages as high torque and remarkable power efficiency packed into a small body that is easy to built into robot joints. The engines comprise few wearable components, which results in decreased maintenance scope and costs. Designed mostly as composite rotor and stator kits, the drives support a variety of mounting options to allow versatile robotic configurations.

Industrial equipment

Direct coupling of a frameless motor to a power train eliminates the need to include more constituent parts, such as bearings or linkages. This means fewer sources of mechanical breakage and faster response and settling times.

Unlike conventional framed drives, frameless motion solutions are designed as stator and rotor kits, which gives more engineering freedom. Low rotor inertia translates into high acceleration rates. Low cogging enables smooth operation. The engines are utilized in different types of industrial machinery—packaging lines, material handling, and other machine tools.

Commercial applications

For commercial applications, frameless motors provide a number of valuable cost optimization benefits. Mechanical robustness guarantees long service life, consistent performance over the entire working lifespan, and minimum trouble with maintenance and servicing. Enhanced power consumption efficiency allows to save money on energy costs. In addition, the drives operate quietly causing no noise disturbance. Floor care equipment, cash dispensing machines, air handling system are just a few examples of commercial use.


In medical applications governed by stringent norms, reliability is a cornerstone requirement, at times critical for survival of a patient. A special construction comprising a minimal set of components enables frameless motors to provide unfailing performance over an extensive lifecycle. The engines ensure smooth motion with insignificant vibration and noise levels. Efficient power utilization and compact footprint make them ideal for portable equipment. Examples of medical devices with frameless drives include ventilation systems, surgical tools, infusion pumps, and automated laboratory testing systems.


Frameless motors boast low torque ripple and low cogging torque, resulting in minimized speed disturbance. That’s why the engines are a good match for printing and scanning equipment where velocity ripple is highly unwelcome. Small in size, the engines can be fitted into constricted spaces and allow for various mounting configurations.   

Purchase, Delivery & Service

  • 1
    Place an Order
    All it takes to place an order is to submit an online request, send us an email, or give us a call. Our technician will advise you on a proper product
  • 2
    Make a Payment
    We issue an invoice based on agreed terms and you pay it up - just as simple as that. If needed, our managers will guide you through the process
  • 3
    Wait for Delivery
    Average lead time for our orders is up to six weeks. We will deliver the purchase right to your door—wherever the door is located
  • 4
    All the products are covered with a 1-year warranty. Each of our customers gets personalized LIVE tech support from the engineering team when requested


  • EAC
    • Complete servo motors RD DC 48V frameless electric motors FMI type (AC 48V power supply).

      Registration number EAC Declaration