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More air performance and high energy efficiency

New Plug Fans exceed today the requirements of tomorrow

With the coming into effect of the ErP (Energy related Products) Implementation Directive for fans, manufacturers are required to design their products for the European market in compliance with defined efficiency standards. These standards affects all fans in the power range 125 W to 500 kW, regardless of whether or not they are used as stand-alone units or as components within another item of equipment or system. Great savings potential can be achieved with the fans employed in ventilation air-conditioning technology, for these are often run with a high operating factor. Modern fans with energy-efficient EC technology have numerous advantages here. Not only do they satisfy both current and future mandatory requirements, they actually exceed them by far, even today. This is equally beneficial to the environment and to the consumer’s purse.

Gallery: the new Plug Fans series

For energy-efficient use in ventilation and air-conditioning technology, ebm-papst Mulfingen has developed the so-called Plug Fans series of fans with GreenTech EC technology, which has already been successfully established on the market. In order to cover higher air performance ranges, the existing range has been extended upwards. Now, the backward curved centrifugal fans with impeller diameters ranging from 250 to 900 mm and power output ranging from 400 watts to 6 kilowatts cover practically every feasible application in the field of ventilation and air-conditioning technology. The volume flow that can be achieved is between 300 and approximately 30,000 m³/h with the necessary pressure increase of up to 1200 Pa. Typical applications include the cooling of large inverters in the field of photovoltaics or for cooling the generators on wind turbines. The fans are available with a special corrosion-resistant hygienic coating, enabling them to be used in hospitals and swimming pools without further ado.

Modern EC technology and thought-out design details

Plug Fans are also available with a special corrosion-resistant hygienic coating

With the development of the series, the overall efficiency of the fans has been optimised with respect to the current and expected future minimum efficiency standards. This was made possible by the choice of materials, by thought-out design details and by the use of the latest EC technology in the drives. Motor, electronics and impeller are optimally configured in order to achieve maximum overall efficiency and material usage, and to avoid unnecessarily large dimensions. For example, the blade geometry of the impeller with diagonal trailing edge improves the aerodynamic characteristics and the running smoothness. The same thing applies for the vent contours realised on the new series. Previously, a standard pressure tap was integrated here to regulate differential pressure via a threaded nipple. A ring circuit is possible on request. The position of the impeller on the external rotor motor has been chosen to produce both aerodynamic advantages and installation advantages.

The motors also satisfy the very highest standards. Even today, the EC drives used in the Plug Fans are just as efficient as motors of efficiency class IE4. In other words they exceed by far the current requirements of the ErP Directive with respect to efficiency. The integrated electronic control system allows their speed to be adapted continuously to the requirements and enable them to work extremely efficiently. They thus consume far less energy than AC drives with the same air performance. However, this energy saving potential is not only realised in full load operation, but primarily when they are operated under partial load. Noise development is very important in connection with ventilation and air-conditioning units. Here too, EC drives are the better choice, because they do not produce any motor noise in a controlled state.

Compact and easy to install

The efficiency plume shows that the fans exceed the required values

Another advantage of Plug Fans is their compact design. The electronically commutated external rotor motor is integrated directly in the impeller. A belt drive between the motor and the fan, which is otherwise commonly used, is not needed (see Fig. 5). This reduces the necessary installation volume. This effect is always desirable, especially in ventilation and air-conditioning units; firstly because the air-conditioning unit can be made smaller, so it needs less material, and secondly because it reduces the amount of space it needs. Machine rooms etc. can then be designed to be smaller from the very beginning. At the same time, fewer parts are subject to wear and less maintenance is needed compared to belt-driven systems, keeping service costs down in the long term. The electronics integrated in the motor also have another practical benefit. The electrical connection only needs an unscreened wire.

Plug Fans are available in various installation versions, e.g. with a “spider mounting” or with a fitted mounting plate for simple anti-vibration mounting. The power electronics integrated in the EC motors are compatible with all common supply voltages; depending on the motor type, either from 200 V to 277 V for single-phase AC or 380 V to 480 V for three-phase current supply. All versions work with a frequency of 50 or 60 Hz. Air performance and efficiency are not affected by the different frequency. In other words, the same type of fan can be used without further ado on various networks worldwide. The choice of the right fan for the application concerned is made easier by an officially certified selection program which is available either as a stand-alone software package or as a DLL module for integration in the user’s specific equipment configuration programs. This can also be used to calculate the life cycle costs for the fan concerned. The user thus knows from the very beginning what savings potential the new Plug Fans can offer him in practical use.

ModBus interface for a simple connection to the control technology

Practical control options are a matter of course with the modern fans. The electronics integrated in the drives are not only ideally matched to the EC motors used, they can also be controlled with either a 0 … 10V analogue signal or digitally with a ModBus interface (greater than 500 W). This makes the connection to the higher order building control system straightforward and practical. Bus networking has important advantages, especially if more than one fan is in use: Starting from configuration during commissioning right through to service, fault diagnosis and maintenance, working with the technical fittings is made substantially easier if the fans can be accessed from a central PC. Apart from the necessary PC software, there is now a smartphone-compatible version available that can be used to remotely (i.e. without cable connection) program, monitor and control the networked fans via a Bluetooth interface.

For maximum air performance

Save space by using EC fans (top), as opposed to systems with AC fan and belt drive (bottom)

For greater air performance, e.g. in centralised air-conditioning units or for cooling IT centres, it is no problem to wire several fans in parallel. Detailed measurements have shown that installation from a distance of about half the impeller diameter between the fans has no significant influence with respect to reducing the air volume and noise behavior.
Such combinations not only increase the air performance but also operating reliability. Should one of the fans fail, the remaining fans will compensate for the lacking air volume. In addition, smaller and lighter fans are vastly easier to install and remove than a large unit. However, this service case is unlikely to occur in practical use. Plug Fans are considered to be extremely reliable and dependable. To keep the bearing load on the motors low and to sustainably withstand the high circumferential speeds, the impellers and their seven backward curved blades are made completely out of aluminium. The material is beneficial for the weight of the fans and at the same time offers a high measure of stability. The individual blades are welded with a continuous seam, which also benefits stability and service life. The fans are designed for a service life of more than 40,000 operating hours. That corresponds to a continuous operation of more than 4.5 years, operating under full load and at the maximum permitted ambient temperature. In partial-load operation or at low ambient temperatures, the service life is substantially longer. This Plug Fan series with GreenTech EC technology gives the user durable, highly efficient, easy-to-control and high-performance fans for many different applications in ventilation and air-conditioning technology.

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  • Proplas on said:

    Thanks for this article, was an interesting read, the developments are certainly interesting!