Frequently Asked Questions

Our breakthrough TFM technology is now proven globally, delivering millions of operating hours in a wide range of applications. Motor technology is what we do.

Can TFM be produced at volume?

PROVEN AT SCALE
  • ETM’s TFM is deployed across 15+ OEM programs currently in production, spanning industrial, commercial, and emerging application segments.
  • TFM materials come from mainstream supply chains: standard laminations, copper, and magnets. There are no exotic or constrained inputs.
  • ETM’s licensing model allows OEM partners to produce using their existing manufacturing infrastructure, which accelerates time to volume and keeps production costs competitive.

Does TFM require a special VFD?

Compatible with conventional drives
  • TFM motors are typically 3 phase and operated with Space Vector PWM, FOC (sine).
  • TFM motors present a relatively typical electrical load, with low inductance and resistance.
  • TFM operating frequency falls within common ranges. Pole counts are higher, but RPMs are lower.
  • TFM motors can use COTS (commercially available off-the-shelf) drives or custom drives.
Rotor sensing
  • TFM is compatible with all rotor position sensing methods: Halls, encoders, resolvers, and sensor-less. TFM has been implemented in challenging motion control with sensor-less commutation.
  • TFM is used in servo applications.
  • System requirements and motion control dynamics typically determine the best sensing approach.

How does TFM cost compare to other motors?

Real world experience
  • TFM typically reduces material content resulting in lowest $/Nm total cost.
drivetrain simplification
  • In many cases, TFM eliminates transmission components (gears, belts) and simplifies installation.
Limited source of supply
  • TFM is a new technology, and few motor factories have experience with the assembly tools and methods. This may increase startup costs compared to RFM
  • Many active TFM patents, license royalties may apply.

Is TFM power factor comparable to other motor types?

General rules for tfm
  • TFM PF is similar to other PM motor types, typically .85-.95 @ rated power.
  • PF is a TFM design input and can be adjusted for custom designs.

Does TFM require rare earth magnets?

MATERIAL FLEXIBILITY
  • TFM is compatible with ferrite-based permanent magnets, avoiding the supply chain risk, price volatility, and geopolitical exposure associated with rare earth materials.
  • Advancing non-rare-earth configurations is an active part of ETM’s technology roadmap.
WHY IT MATTERS
  • OEM partners gain a path to a more resilient, cost-stable motor supply chain without sacrificing torque density performance.

How do I get TFM technology for my product?

ETM’S LICENSING MODEL
  • TFM is available through ETM’s flexible technology licensing program, modeled similarly to ARM in semiconductors.
  • OEM partners license the TFM architecture and can manufacture using their own production infrastructure or work with ETM on contract manufacturing options.
  • Either path gives you full control over your product positioning and go-to-market timing.
WHAT’S INCLUDED
  • ETM provides the validated motor architecture, design support for your specific application, and manufacturing guidance to support production launch.
  • Licensing can include custom TFM designs optimized for your performance requirements and duty cycle.

Will my motor operating frequency be high?

transverse flux motor technology
  • Although TFM has exceptionally high pole count, operating frequencies fall within the typical synchronous motor range. TFM RPM tends to be on the low side (direct drive) and pole count selection considers available drive frequency. Most TFMs operate below 600 Hz.
  • Some TFM customers spec higher frequency TFM to match their inverter. This further improves power density.
pwm frequency
  • TFM inverters are switched at commonly seen PWM frequencies, based on drive specs and acoustic concerns.
    • 5-18 kHz is typical.

Is TFM noisy?

Real world experience
  • TFM often eliminates belts and gears, making the system run significantly quieter.
    • Examples:
      • 20-40 HP Axial Fans (DD vs. gears and belts).
      • HVLS Fans (DD vs. gears).
      • Paint Sprayers (DD vs. gears).
  • TFM is successfully commercialized in noise-sensitive applications
  • State-of-the-art TFM cogging torque is <5% Peak-to-Peak/Rated Torque. For lower specs, consult with TFM supplier.

What is the downside?

Technical fit
  • Low duty cycle (Peak Torque/Rated Torque > 2) and speeds over 5k RPM are less likely to fit TFM.
  • Exceptionally low cogging specs may be a challenge for TFM.
Challenging to design
  • 3D simulation is required.
  • Many active patents.
  • TFM licenses can include custom designs.
Limited supply base
  • Although TFM materials come from mainstream suppliers (laminations, copper, magnets), assembly houses are limited and quoting new designs can be a barrier to entry.
  • TFM can be licensed, enabling existing contract manufacturer and in-house production.

Is TFM patented? Can we develop it independently?

ETM’S IP POSITION
  • TFM sparked interest in engineering circles for decades but consistently resisted practical manufacturing until ETM cracked production-scale manufacturability in 2007 after years of sustained investment in design and process development.
  • TFM is now protected by 100+ patents worldwide covering core architecture, design configurations, and manufacturing methods.
  • Independent development carries significant IP risk and would require substantial investment in 3D simulation, tooling, and process development.
THE PRACTICAL PATH
  • ETM’s licensing model gives partners access to a validated, production-proven architecture without the time and cost of starting from scratch.
  • Licensing includes design support, manufacturing guidance, and a faster path to market than internal development allows.

TFM adopters tend to value

  • Going direct drive to eliminate gears and belts.
    • TFM has been able to direct drive systems that were previously geared up to 30:1.
  • Smaller and/or lighter motor.
  • System efficiency.
    • Especially across their load and speed range.
  • Elimination of rare earth metals.
  • Simplified cooling designs.

Best fit applications

  • High duty cycle – continuous or repetitive.
    • The motor size is based on thermal performance.
  • Low peak/continuous torque ratio.
    • Ideally < 2:1.
  • Air cooled or non-ventilated.

Partner with ETM

ETM licenses TFM technology to OEMs whose applications demand higher torque, lower weight, or drivetrain simplification. Talk to our engineering team about fit for your application.

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