Centrifugal Inline Fans: ebm-papst (AC Motors)

An electronically commutated (EC) motor operates from a standard alternating current (AC) power supply but, in design and operation, closely resembles a direct current (DC) motor. It is essentially a brushless, permanent-magnet DC motor with integrated electronic control built directly into the motor housing. This allows EC motors to combine the simplicity and robustness of AC motors with the efficiency, controllability, and smooth operation of DC motors — placing them in a category of their own.

By using this technology, EC fans achieve exceptionally high efficiency, particularly at part-load operation, where traditional motors perform poorly. Lower energy consumption, reduced heat generation, and smoother operation contribute to lower running costs and a longer service life, allowing EC motors to effectively pay for themselves over time. They also provide a range of operational advantages that are often overlooked in basic specifications.

EC motors generate their magnetic fields using permanent magnets in the rotor and electrically energised windings in the stator, similar to a brushed DC motor. However, instead of relying on mechanical brushes for commutation, EC motors use electronic commutation. This is made possible by on-board electronics integrated within the motor itself.

These electronics include a rectifier that converts the incoming AC supply into DC power. An integrated controller then precisely regulates the timing, direction, and magnitude of current delivered to each stator winding. Hall effect sensors continuously monitor the position of the rotor magnets, allowing the controller to energise the correct windings at exactly the right moment.

This electronically controlled sequence of magnetic attraction and repulsion produces smooth, efficient rotation with optimal torque at all speeds. Because the entire process is managed electronically, EC motors allow for precise speed control, continuous performance monitoring, and highly efficient operation across the full operating range — making them ideal for high-performance, low-noise ventilation systems.

AC motors are a cost-effective option that still deliver excellent ventilation performance. They are well suited to ducted systems, operate quietly, and are capable of moving large volumes of air efficiently. AC motors run at a single fixed speed, which is typically the point at which they operate most efficiently. This makes them a reliable, straightforward solution where consistent airflow is required.

EC motors build on this performance by offering advanced control and efficiency across a wider operating range. In real-world use, EC motors are capable of higher airflow, smoother fan rotation, and significantly quieter operation — particularly when run at reduced speeds. At lower fan speeds, EC motors can operate almost silently while consuming very little power, making them ideal for noise-sensitive installations or applications requiring longer daily run times.

Because EC motors feature fully adjustable speed control, airflow can be precisely matched to the size, layout, and moisture conditions of the installation. Unlike traditional motors, EC motors remain highly efficient at all speeds, not just at full output. This results in lower energy consumption, reduced wear on components, and greater long-term flexibility if ventilation requirements change over time.

In summary, AC motors offer excellent value and proven performance, while EC motors provide superior efficiency, control, and ultra-quiet operation for high-performance and future-proof ventilation systems.

Energy Efficiency

EC motor efficiency commonly exceeds 90%, allowing EC centrifugal fans to use up to 70% less energy than conventional AC fan systems. Because power consumption drops rapidly as speed is reduced, running an EC fan at around 80% speed can deliver close to a 50% reduction in energy use, while still maintaining effective airflow. This makes EC fans ideal for continuous or long-duration operation without high running costs.

Ease of Control

EC motors continuously monitor their own operating conditions and automatically adjust power input to maintain high efficiency across the entire speed range. Unlike traditional motors, which are only efficient at one operating point, EC motors remain highly efficient even at very low speeds. Many EC motors can be reduced to around 20% of full speed while still maintaining efficiencies of approximately 85%. Speed control is achieved via simple 0–10 V signals from timers, sensors, or controllers, eliminating the need for complex and inefficient variable frequency drives.

Versatility and Performance

EC motors are capable of operating beyond their nominal rated speeds when required, allowing higher airflow to be achieved from a smaller fan assembly. This enables more compact, flexible system designs without compromising performance. The combination of variable speed control, high efficiency, and compact power density makes EC motors exceptionally well suited to modern ventilation systems where quiet operation, energy efficiency, and adaptable airflow are critical.

Our Low Profile fan housing is specifically designed for installations where access height is limited. With an oval profile measuring 340 mm wide and just 217 mm high, it offers a significantly smaller footprint than standard housings, making it ideal for shallow or restricted spaces without compromising performance.

The latest Low Profile design incorporates updated internal air deflection fins, engineered to guide airflow more smoothly through the housing. These improvements reduce internal turbulence, resulting in marginally higher airflow and slightly lower noise levels compared to the previous Normal Profile version.

By combining a compact form factor with refined internal aerodynamics, the Low Profile fan housing delivers efficient, quiet operation in installations where space constraints would otherwise limit fan selection. This makes it a reliable solution for achieving effective ventilation in low-clearance environments.

AC motors are single speed motors. They run at 100% all the time.

Our AC centrifugal fans are designed to operate very quietly in real-world installations.

It’s important to understand that decibel ratings on their own can be misleading. Noise figures are typically measured in controlled test conditions and do not account for factors such as ducting, fan suspension, building structure, or installation method. In practice, the perceived noise of a fan is influenced far more by how it is installed than by a single published dB figure.

In real installations, our AC fans are suspended using anti-vibration straps and connected to ducting on both the inlet and outlet sides. This significantly reduces structure-borne noise and attenuates airflow noise, resulting in very low perceived sound levels inside and outside the home during operation.

While AC motors operate at a fixed speed, they are engineered to run at an efficient and stable operating point. The combination of centrifugal fan design, proper ducting, and vibration isolation ensures quiet, consistent performance without the tonal motor noise often associated with lower-quality fans.

In short, our AC centrifugal fans deliver reliable airflow with impressively low noise levels, making them a proven and effective solution where simple, quiet, fixed-speed ventilation is required.

Decibel ratings are often misunderstood and, in many cases, misused. On their own, dB figures rarely reflect how loud a fan will actually sound once installed in a real building. Unfortunately, some manufacturers take advantage of this by publishing selectively measured or unrealistic noise figures that do not represent real-world performance. Some manufacturers are simply dishonest. Please see our Instagram post HERE and our Instagram video HERE for a good explanation of the issue.

Firstly, decibel ratings are typically measured under laboratory conditions that bear little resemblance to an installed environment. Measurements may be taken at unrealistic distances, at reduced fan speeds, without ducting attached, or in free-air test rigs. This makes it very easy to publish an impressive number that does not translate to real installations in homes.

Secondly, not all noise is perceived equally. The frequency of the sound (its pitch) is often far more important than the overall decibel level. Many fans with low published dB ratings produce a noticeable high-frequency motor “whine”. This type of noise travels easily through building materials and is particularly intrusive to occupants. By contrast, our centrifugal fans predominantly generate airflow noise rather than motor noise. Once installed, airflow noise is largely attenuated by ducting on either side of the fan, while motor whine continues to transmit through structures.

Thirdly, decibel scales are logarithmic, not linear. A small numerical difference in dB can represent a significant perceived difference in loudness, yet manufacturers often quote figures without context or explanation. This makes side-by-side comparisons meaningless unless the test methods are identical and independently verified.

We have been installing ventilation systems for over 15 years and have tested virtually every fan available on the market, including all major competing models. Based on extensive real-world installation experience, we are confident that our fans are quieter in installed conditions than any comparable models currently available.

Importantly, our decibel ratings have been independently tested in Australia by VIPAC Engineers & Scientists Ltd, providing credible, third-party verification rather than marketing-driven claims.

For a clear visual explanation of why published noise figures can be misleading, we recommend viewing our Instagram videos linked above, which break this issue down in simple, practical terms.

In summary, decibel ratings alone do not tell the full story. Installation method, operating speed, sound frequency, fan design, ducting, and vibration isolation all have a greater impact on perceived noise than a single dB number. This is why real-world performance and proven installation experience matter far more than headline specifications.

The fan motors are manufactured by ebm-papst in Germany.

Yes. All of our fan housings are custom injection moulded in Melbourne by Shale HVAC, exclusively for Fresh Ventilation. They are manufactured using high-quality, virgin ABS resin with a V0 fire retardant rating, providing excellent strength, durability, and fire performance.

Producing our fan housings locally allows us to maintain strict quality control, refine designs based on real-world installation feedback, and ensure the housings are suited to Australian conditions. The result is a robust, purpose-built housing that supports quiet operation, reliable airflow, and long-term performance in demanding environments.

Yes. Our fans have been independently tested and certified for Australian electrical safety compliance. They carry the Regulatory Compliance Mark (RCM), confirming they meet the relevant Australian Standards and are registered under the Electrical Equipment Safety System (EESS) for legal sale and safe use in Australia.

All testing and certification was conducted by VIPAC Engineers & Scientists Ltd, an accredited independent testing authority. This provides assurance that our fans meet strict Australian requirements for electrical safety, performance, and compliance, giving you confidence that the equipment is safe, reliable, and approved for use in Australian homes.

For residential electrical installations in Australia, fan motors are required to be manual restart as part of meeting safety expectations under the Regulatory Compliance Mark (RCM) framework.

In this context, manual restart refers to how a motor behaves when a fault is detected, such as overheating or internal electrical failure. A manual restart motor shuts down and remains off once a fault occurs. The motor must then be repaired or replaced before it can operate again. This behaviour is intentional and forms a critical safety mechanism, preventing continued operation of a faulty appliance.

By contrast, auto restart motors are designed to stop temporarily when a fault is detected and then automatically attempt to restart after a delay. If the underlying fault remains, the motor can repeatedly stop and restart. This fault-cycling behaviour significantly increases electrical stress and heat build-up and may cause a fire.

Australian residential electrical safety requirements are deliberately conservative in this regard. The expectation is that appliances installed in homes should not repeatedly re-energise themselves after a fault, as this presents an unacceptable fire risk.

Many fans available on the Australian market are nevertheless auto restart. This is largely because they are designed for overseas markets where this requirement does not exist. Australia represents a very small portion of the global fan market, and many manufacturers simply supply globally standard products that are compliant elsewhere but not appropriately configured for Australian residential use. In many cases, this distinction is not clearly disclosed.

Based on our understanding of the local market, we believe our fans are among the very few available in Australia that are genuinely manual restart, specifically selected and configured to meet Australian residential electrical compliance expectations under RCM.

This is not a marketing feature — it is a safety requirement. And it is one that is often overlooked.

The fan motors have a 5 year warranty.

AC motors have a protection rating of IP 44.