Axial Fans Propel the Shift from AC to EC Motors

Fans are critical system components for cooling systems, particularly in applications such as supermarket refrigeration, HVAC, and telecommunications cabinets. Electronically commutated (EC) motors changed the game for many designers because they let fans run at exactly the speed needed, unlike alternating current (AC) motors that often must run at full tilt even when a cooling application doesn’t need it.

Fans running at an appropriate speed means less energy, less noise, and less stress on components than the shaded-pole and permanent split capacitor (PSC) motors that, for many years, were the staples of fan and blower applications. The motor, however, is simply what is needed to make a fan spin, causing the necessary air movement to chill refrigeration units and cool off electronics.

Shaded-pole motors waste a significant amount of energy as heat, and operate at a fixed speed determined by the mains frequency. PSC motors offer some performance improvement, but their efficiency still peaks near full speed.

An EC motor converts AC voltage to DC and runs a fan efficiently at the appropriate speed. This enables designers to utilize smaller power supplies, reduce operating costs, and comply with modern efficiency standards.

EC motors combine brushless DC motors with integrated electronics for higher efficiency, precise speed control, and greater flexibility. Electronic commutation manages current to the motor windings in a controlled sequence, which is ideal for digital and electronically controlled applications.

Rapid adoption of EC fans

For many years, the costs of electronics and magnets made it difficult to justify the added material costs for an EC motor when a simple shaded-pole or PSC motor would get the job done. As power electronics became cheaper and energy costs climbed, EC was eagerly adopted for premium HVAC systems and other equipment where variable speed and quiet operation were prized.

With an EC motor, fans can ramp up or down in response to temperature, pressure, or network signals. Bearings last longer, start-up currents are gentler, and maintenance intervals can stretch. Plus, one fan model can be used across multiple SKUs. Fan makers responded by integrating EC technology into complete assemblies that can fit into existing designs with minimal fuss.

EC fans are now standard in many new commercial refrigeration units, HVAC blowers, and telecom racks. In North America, over half of new commercial HVAC systems ship with EC motors, and supermarket refrigeration retrofits provide fast paybacks in energy savings. AC motors haven't disappeared, of course, and often are relied on for low-cost, fixed-speed applications where part-load efficiency is not a priority.

Drop-in AxiACi replacements from ebm-papst

As an early innovator in integrating brushless DC motors with compact, high-efficiency fan designs, ebm-papst has been a driving force in the adoption of EC motor technology for fans and blowers. The company's fans combine the motor, control electronics, and aerodynamically optimized impellers in a single package, allowing for quiet operation, precise speed control, and significant energy savings.

The company’s AxiACi series fans (Figure 1) are designed as drop-in replacements for legacy AC fans, offering designers a practical path to update cooling applications with energy efficiency savings and modern performance without requiring major retrofitting.

Figure 1: The AxiACi series fans incorporate EC motors for replacing older AC-based solutions. (Image source: ebm-papst)

AxiACi units combine rugged durability and wide environmental tolerance, operating in a temperature range of -40°C to +75°C. They provide a global voltage range of 90 VAC to 264 VAC (50/60 Hz) and utilize a three-phase multi-pole motor that reduces structure-borne noise.

With a service life of 65,000 hours, the ebm-papst fans are an optimum replacement for outdated solutions. They utilize highly efficient GreenTech EC motors and EC-level efficiency in an AC package to bridge the gap between traditional AC fans and fully electronically-commutated solutions.

An AxiACi120 model, such as the 8315100190, is a solid option for replacing older AC fans in cabinet cooling, industrial ventilation, or refrigeration. The tube axial design measures 119 mm x 119 mm × 38 mm, and delivers roughly 101 CFM while running from a universal 115/230 VAC supply. It is IP65-rated for dust and water-jet protection and designed to operate in extreme ambient temperatures from -40°C to +70°C, making it an ideal drop-in upgrade. 

For designs that need a more compact option, AXIACI92U models like the 8315100286 measure 92 mm x 92 mm x 38 mm and are suitable for tighter spaces and applications that rely on lighter-duty cooling. Despite offering more moderate airflow, it delivers an impressive static pressure of 0.622 in H₂O (155 Pa) that is capable of pushing air through restrictive filters, grilles, or downstream ducts.

Conclusion

To meet the shift to EC fans for commercial refrigeration, HVAC, and industrial settings, ebm-papst's AxiACi series provides reliable, energy-efficient drop-in replacements for older AC fans. The AxiACi models offer enhanced durability, quiet operation, wide voltage compatibility, and improved performance across extreme environments, making them ideal for upgrading existing systems without extensive retrofitting. Compact versions are also available for applications with space constraints, ensuring versatile solutions for modern cooling needs.