The Problem
Most axial fans of the "compact class" still use the old shaded-pole motor AC technology, despite the very poor efficiency of these motors compared to DC technology. Intelligent fan control and monitoring options are also very limited. Until recently, the main barrier to improvement has been that DC technology could not be operated directly from the AC mains supply. A solution became available with the introduction of the ebm-papst ACmaxx series of compact axial fans.
The Goal
The aim in developing the ACmaxx series was to raise the technology standard of the conventional AC fan significantly, while facilitating the transition to the new technology. The latter goal was accomplished by retaining the mounting dimensions of the equivalent AC fans and by providing the capability in a single fan to operate on AC mains power around the world. Raising the technology standard was achieved through a new drive concept.
The Design
The drive concept of the ACmaxx is based on ebm-papst Green Tech EC (Electronic Commutation) technology combined with an internal power conversion module. The result is outstanding motor efficiency, with energy consumption up to 77% lower than comparable AC fans. Since the energy saved is no longer being turned into waste heat that would otherwise increase motor temperature, the motor bearings run cooler and last longer. This combination of a longer service life and lower energy consumption across that life means an ACmaxx fan pays for itself in short order.
An additional benefit to the built-in electronics is that a wide variety of control and monitoring options can be offered, similar to ebm-papst DC fans. These include tachometer output, fault alarms, standby mode, temperature-dependent speed control and PWM/analog speed control.
Lastly, there is the flexibility provided by the worldwide power capability. ACmaxx fans are prepared for direct connection to the wide range of AC mains voltages and frequencies seen across the world. The fan performance remains constant between 85-265VAC and 50/60Hz. Voltage fluctuations in the power system are compensated for automatically. A single p/n can be used to simplify purchasing logistics for platforms or markets that operate on different AC mains supplies.
The Next Stage... ACi4400 series
At ebm-papst we never sit still. We anticipate the future needs of customers every day. Our next stage in the ACmaxx evolution - the GreenTech EC compact fan series - is another step toward raising the technology bar of AC mains powered compact axial fans. The initial series released for this new generation is the 119mm x 119mm x 38mm ACi4400.
It's more compact...
Although not typically an issue, the one area where ACmaxx models exceed the size of comparable AC fans is at the strut hub. The GreenTech EC compact fan design brings the hardware that protruded beyond this surface inside the fan housing, making the ACi4400 models identically sized to the AC fans they replace.
It's more efficient...
ACmaxx saves a lot of energy, and the GreenTech EC compact fan generation saves even more. While compact AC axial fans often have overall efficiencies of under 10%, the ACmaxx achieves 20-25%. The ACi4400 series reaches a remarkable level of up to 30%. This is the result of the optimization of the entire package consisting of the drive, electronics, power conversion and aerodynamics.
It's quieter...
The ACi4400 is quieter than AC fans and quieter than the existing ACmaxx generation. This was mainly achieved through further improvements in aerodynamics and in reducing structure-borne noise. This results in the ACi4400 series fans typically being 3dB quieter than an AC fan of the same size and comparable performance and as much as 6dB quieter at some operating points.
Compromises...
Advances in one area sometimes means compromises in another. One of these was the ability of a single fan to run on any AC mains power worldwide. This is still true for the 50/60Hz frequency range. But insufficient room for the necessary electronic components meant the GreenTech EC compact fan voltage range had to be handled by separate 115V and 230V models. Each of these models still accepts a wide voltage range of 85 to 132V and 195 to 265V, respectively. More importantly, the GreenTech EC compact fan performance remains constant over each voltage and frequency range, as with the ACmaxx models.
Again because of insufficient room for the needed components, the control and monitoring options available in ACmaxx models are not currently available in GreenTech EC compact fan. In the future we expect that some form of speed control or monitoring will be possible.
ACmaxx / GreenTech EC compact fan... a new choice for the compact AC axial fan world
Whether in control cabinets, refrigeration technology, filter fans, medical devices or in the myriad of other applications where AC fans are commonly used, there is no stopping the change from the old AC motor technology to ebm-papst fans with Green Tech EC technology. So out with the AC, in with ACmaxx / GreenTech EC compact fan- it's that simple.
