When is Installing an Ultra-Compact Motor an Ultra Mistake?

Recent advances in motor technology have introduced ultra‑compact, high‑power motors, such as direct flux and axial flux designs, that deliver performance comparable to much larger motors but weigh far less. While these motors are promising for new, space-constrained applications, they may not always be ideal for older facilities.

HECO can help you understand these motors and when to utilize them for the best results in your application.

Emerging Motor Types

Axial flux motors are gaining attention for their compact, disc-shaped design and impressive performance capabilities. Unlike traditional radial motors, these units are shorter and wider, allowing for a larger effective diameter and shorter magnetic path. According to Stanford Magnets, this setup can deliver up to four times more torque per volume and slightly better energy efficiency (around 1–2% in most cases). Their shape also lends itself well to space-constrained applications like EVs, drones, and aerospace systems.

Another emerging design is the transverse, or direct flux motor, which is built for high torque at low speeds. These motors work well in direct-drive applications by removing the need for gearboxes and helping reduce total system weight. In fact, in some use cases like peristaltic pumps in industries like the food and beverage industry, the motor size can be reduced by over 70% according to Pumps & Systems.

Cons and Integration Challenges

While these ultra-compact, high-powered motors offer several benefits, including exceptional power density, efficiency gains, system simplification, and convenient integration with new equipment and facilities, the replacement of large motors with small direct motors can be challenging beyond small equipment such as pumps and fans.

With existing facilities, drawbacks to utilizing ultra-compact motors may include:

• Higher upfront cost and manufacturing complexity – Advanced materials, rare-earth magnets, and precision disc construction can raise production and purchase costs.
• Motor control reliance – The majority of axial flux motors require a variable frequency drive to operate effectively in most cases, whereas the standard squirrel cage motor can be started across-the-line.
• Thermal management and mechanical stress – Compact design can make cooling and heat dissipation more complex, particularly under heavy load or prolonged operation. Their smaller weight can also exacerbate vibration damage when attached to heavy loads.
• Mounting and retrofit barriers – Smaller units and mounting needs often require wall or flange mounting unlike the floor-based construction of heavy motors that mount to baseplates. Retrofitting older equipment requires mechanical redesign and custom adapters.
• Lower suitability for high-power loads – While great for small pumps, fans, and conveyors, these motors may struggle to match the performance envelope of traditional Above-NEMA equivalents when matched by weight alone, and efficient scaling can be cost-prohibitive.

Unless your application calls for compact, low-power needs or is part of a new build where existing mechanical fits are not a constraint, ultra-compact motors will likely cause more work, investment, and inefficiencies than utilizing a standard, large motor.

In older facilities with large, foot-mounted motors that are deeply integrated into mechanical systems, retrofit costs and incompatibilities may outweigh efficiency gains. High-power legacy systems requiring robust, floor-mounted drives over extended operational periods are also better candidates for larger, more traditional motors.

All Systems Go

Context, as well as initial and ongoing mechanical and cost impacts, are key motor selection considerations.

At HECO, we understand both traditional and modern motor ecosystems. Whether you’re planning a retrofit, modernization, or new-scale design, our experts can help assess your unique load, footprint, and mounting requirements so you get the most effective solution.

Want to know if a compact motor is the most effective motor for your facility, or if a traditional upgrade makes more sense? Let’s talk about your application and the possibilities.

Posted in Product Sales