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Frameless torque motor

Allient MegaFlux frameless torque motors

Frameless direct-drive brushless torque motors in 12 diameters from 60 to 330 mm, continuous stall torque up to 181 Nm, 48–300 V DC bus and clear apertures up to 582 mm.

Need this part, a replacement or a complete package? Our experienced UK engineering team helps you select, source and obtain the right products, with pricing, delivery coordination and after-sales support.

Pricing and availability

Get pricing, sourcing and replacement support

Need Allient parts, a replacement or a suitable alternative? Send us a part number, or tell us what the machine needs to do. Our UK engineers will come back with the right product, pricing, lead time and delivery, whether that is the original part, a checked alternative or a complete axis.

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Spec builder

Specify what you need instead of MegaFlux frameless torque motors

Select every part you need and answer the questions an applications engineer would ask. Our engineers use your specification to come back with the right products, pricing and lead times. You see your summary before we ask for any details.

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  1. 1Products
  2. 2Performance
  3. 3Environment
  4. 4Volumes
  5. 5Your spec
Step 1 of 5

What are you specifying?

Select everything you need. A motor, drive and gearbox can be specified together as one axis.

1 selected: Frameless / torque motor

Key specifications

Voltage (max)300 V
Outer diameter60–330 mm
Inner diameter (max)230 mm
Continuous torque (max)181 Nm
Rated speed330–4,000

Summarised in our own words from Allient Inc.'s published data; series maxima, individual models vary. Last checked 2026-10-30. Source 1

Notes on this data

Peak torque not on the product page. Page also cites clear ID aperture up to 582 mm.

Specify Motion is not affiliated with Allient Inc.. Allient and MegaFlux frameless torque motors are used only to identify the product. Comparisons use published figures; always confirm against the current datasheet.

Allient MegaFlux frameless torque motors replacement and alternative options

Use these supply-network options as a starting point for an engineering check. We can also help source the original Allient part. Published series figures do not establish an exact-model or drop-in replacement: confirm ratings, fit, interfaces and approvals for your application.

Frameless torque motor

Akribis Systems ADR-P

Limited published data: 1 figure compared

High-voltage (600 VDC) frameless torque motor kits from 110 to 360 mm with large through-bores and integrated Hall sensors; the high-torque end of the Akribis frameless range.

Published maximumMegaFlux frameless torque motorsADR-P
Continuous torque181 Nm365 Nm meets or exceeds
Peak torque—985.5 Nm
Housed direct-drive motor

Akribis Systems ADR-A

Limited published data: 1 figure compared

Housed iron-core direct drive rotary motors with bearings and optical encoder, 110-360 mm frames, up to about 1 kNm peak at 600 VDC.

Published maximumMegaFlux frameless torque motorsADR-A
Continuous torque181 Nm407.2 Nm meets or exceeds
Peak torque—1,017.9 Nm
Speed—2,000 rpm
Housed direct-drive motor

Akribis Systems AXD

Limited published data: 1 figure compared

Low-profile housed iron-core direct drive motors with large centre holes and incremental encoders, 80-400 mm frames.

Published maximumMegaFlux frameless torque motorsAXD
Continuous torque181 Nm250.6 Nm meets or exceeds
Peak torque—648.9 Nm
Speed—3,000 rpm

Figures are the highest published for each series and are not always measured the same way. A higher figure is not automatically a better choice: mounting, duty cycle, feedback, connectors and approvals matter too. An engineer will check the fit against your application before recommending anything.

Typical applications

Rotary tablesGimbals and pointing systemsRobot joints

What a frameless torque motor is

A frameless torque motor is a permanent-magnet brushless motor supplied as two parts, a rotor and a stator, with no housing, bearings or shaft. The machine builder mounts the rotor directly on the driven shaft and the stator in the machine structure, so the motor becomes part of the mechanism. Many have large through-holes and high pole counts, giving high torque at low speed with no gearbox. They need separate feedback, typically an encoder, and a servo drive.

When engineers choose a frameless torque motor

Choose a frameless motor when you want direct drive in a compact, integrated design, such as robot joints, gimbals, rotary tables and medical devices. Removing the gearbox eliminates backlash and improves stiffness and smoothness. The trade-offs are integration work and size: the builder supplies bearings, alignment, cooling and feedback, and torque per volume is lower than a geared solution. For off-the-shelf installation, a housed direct-drive motor may be simpler.

How to specify the Allient MegaFlux frameless torque motors

Send these with your enquiry and an engineer can confirm the right MegaFlux frameless torque motors variant or an equivalent:

  • Continuous and peak torque (Nm)
  • Speed (rpm)
  • Outer diameter, bore and stack length (mm)
  • Bus voltage and current (V, A)
  • Thermal mounting and cooling
  • Feedback type and resolution
  • Air gap and concentricity tolerance (mm)

Common mistakes to avoid

  • Leaving air gap and concentricity tolerances undefined
  • Ignoring heat conduction from the stator into the housing
  • Using an encoder with too low resolution for direct drive
  • Forgetting rotor magnet attraction during assembly

Allient MegaFlux frameless torque motors: frequently asked questions

Can you help replace Allient MegaFlux frameless torque motors or source the original?

Send the full model code, quantity and required date. Our engineers can check original-part availability and assess suitable alternatives, including supply-network options where appropriate. We confirm compatibility and any changes needed before recommending a replacement.

What is the Allient MegaFlux frameless torque motors?

Frameless direct-drive brushless torque motors in 12 diameters from 60 to 330 mm, continuous stall torque up to 181 Nm, 48–300 V DC bus and clear apertures up to 582 mm. Published series figures include voltage 300 V, outer diameter 60 mm, outer diameter 330 mm, inner diameter 230 mm. It is made by Allient Inc.; Specify Motion can help source it or propose an equivalent.

Who makes the Allient MegaFlux frameless torque motors?

The Allient MegaFlux frameless torque motors is made by Allient (Allient Inc.) and is listed here for engineers comparing options. Specify Motion is not affiliated with Allient Inc.; brand names are used only to identify the product.

What is the voltage of the Allient MegaFlux frameless torque motors?

The published series maximum voltage is 300 V. Individual models and sizes in the MegaFlux frameless torque motors range vary, so check the exact variant against your duty cycle, mounting and environment, or ask our engineers to confirm the right size for you.

Is there an alternative to the Allient MegaFlux frameless torque motors?

We can assess suitable replacement options. On published figures, Akribis Systems ADR-P and Akribis Systems ADR-A are options to assess from our supply network. An engineer confirms the fit against your application before recommending anything.

What is the difference between a frameless and a housed torque motor?

A frameless motor is only a rotor and stator; the machine provides bearings, shaft, housing and feedback. A housed direct-drive motor adds bearings, housing and encoder in a ready-to-install unit. Frameless suits compact, integrated designs where the machine already has stiff bearings; housed suits faster installation and simpler alignment.

Why use a frameless motor instead of a gearbox?

Direct drive removes backlash, wear and compliance in the gear train, giving smoother motion and stiffer control. It also allows a large hollow shaft for cabling. The trade-off is that torque must come from the motor alone, so it is larger for a given torque.

Further reading: How to select a frameless torque motor · Frameless motor sizing robot joints · Frameless and torque motors

Other frameless torque motor series

Engineer support

Let our experienced engineers do the hard work for you

Tell us how you use the Allient MegaFlux frameless torque motors: the load, speed, duty and environment. Our engineers will confirm whether it is still the right part, find it for you, or propose an alternative that fits better.

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How it works

From enquiry to delivery

Send a part number or describe the application. Our engineers take it from there: the right product, a clear quotation, and delivery and support arranged.

  1. Tell us what you needSend a part number, or configure the application, quantities and timing.
  2. An engineer reviews itWe check the specification and find the original part, a checked equivalent or a complete axis.
  3. Receive your quotationProducts, pricing, lead time and compatibility notes in one reply.
  4. Order and deliveryWhen you are happy, the order is placed and delivery and after-sales support are arranged.