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Frequency Converters

Fans and ventilation concepts for frequency converter cooling

Frequency converters are used for variable speed control of electric motors. They convert the defined frequency and voltage of the electrical energy into a variable frequency and voltage. In this way, the speed and torque of motors, machines and systems can be precisely adapted to the requirements of the respective application, and the energy efficiency of the motors or systems can also be improved.

Due to the general trend to automate plants and processes more and more, the demand for frequency inverters is increasing. The devices are being used in more and more areas to optimize motor operation and the system connected to the respective electric motor.

Increasing automation and digitalization in industry, such as small and large process plants, has led to a continuous search for better technologies and methods to increase the (energy) efficiency of production facilities. Not only in large companies, but also in commercial buildings, public buildings and small craft businesses, the speed-controlled electric motor is now a standard element.

Powerful three-phase asynchronous motors and other motor technologies such as permanent magnet motors or synchronous reluctance motors often have to be controlled with frequency converters, since in many cases direct start-up via the mains supply is no longer possible due to the high inrush current.

The power spectrum of frequency converters ranges from a few watts to more than 100 MW. Although the efficiency of frequency converters is now generally over 95%, there is always a certain percentage of power loss, typically in the form of heat.  This heat must be dissipated either by natural convection, water cooling or air cooling with the aid of fans.

For cooling frequency converters, ZIEHL-ABEGG offers fans of high reliability, long service life and optimum energy efficiency. We build and supply cooling and ventilation systems with globally recognized certifications for numerous applications in the commercial and industrial sectors.

Highly efficient ventilation and cooling concepts for contemporary engine control systems

Systems for controlling or changing the speed of an electric motor are known by various names. The terms frequency converter (FC), adjustable speed drive (ASD), variable speed drive (VSD) and adjustable frequency drive (AFD) are used particularly frequently. In this field, the term "inverter" is often used. A distinction is also made between LV drive (Low Voltage Drive) and MV drive (Medium Voltage Drive).. 

In addition to optimizing energy efficiency and controlling and improving processes, the goals for using frequency inverters include ever-improving factory automation. Furthermore, a control system with speed regulation leads to more precision, more comfort and a generally higher product quality.

Today, modern motor systems increasingly include special software that allows access to new, additional functions, thus ensuring that the importance of frequency converters in the motor system continues to grow.

The energy efficiency of the system is not only gaining in importance due to increasingly stringent standards, but modern motor technologies now fundamentally require sophisticated control. This is the only way to ensure optimum operation in every speed range. In addition, the continuous improvement of energy efficiency is an important step on the way to environmentally friendly technologies, which are characterized above all by energy savings and optimum energy utilization.

several big frequency inverters in a row

Challenges in frequency converter cooling

All over the world, frequency converters are operated on different supply networks. Therefore, the fans used for cooling must also be able to be operated at different frequencies and voltages. The wide voltage range of ZIEHL-ABEGG fans, as well as the globally recognized certifications of our products, ensure that you always play it safe with our fan concepts and remain at the cutting edge of technology.
With our energy-efficient, quiet and reliable fan technology, we are happy to support you in the construction and operation of highly automated systems. We supply individual fans or sophisticated complete systems that are precisely suited to the area of application and the respective installation environment.

The absolute reliability and operational safety of the fan is particularly important when cooling frequency converters. Particularly in the case of larger drives with higher power, the failure of the fan can result in property damage and loss of production.
Since high temperatures can quickly develop on sensitive components in the inverter, especially during startup, the ramp-up time of the ventilation and cooling system is very important. Likewise, an interruption in cooling can lead to damage to the inverter or a reduction in the power of the drive and thus to production losses. Therefore, it is important to detect critical situations of the cooling system before a failure occurs - for this purpose ZIEHL-ABEGG offers solutions which can be implemented by the customer. To reduce the risk of failure, redundant cooling systems are often used - for this purpose ZIEHL-ABEGG provides suitable communication modules to be able to control redundant systems precisely.

Fans and air handling systems from ZIEHL-ABEGG for frequency converter cooling

A common method of cooling frequency converters is forced ventilation. Here, fans guide cool air over the hot components and thus dissipate the excess heat.
Smaller frequency inverters with lower transmission power, the LV or Low Voltage Drives, often use small axial fans for this purpose. In contrast, frequency inverters of larger design and higher transmission power, the so-called MV or Medium Voltage Drives, are often cooled with centrifugal fans. These convey the air from bottom to top through the entire inverter and must therefore overcome high differential pressures. For this purpose, the fans are either mounted on the cabinets or housings of the frequency inverters or installed in the frequency inverters.

The universal biomimetic fan concept from ZIEHL-ABEGG guarantees maximum reliability in any voltage range with compact design, low noise and best energy efficiency. We will be pleased to advise you on the fans best suited to your application and provide you with reliable and competent support from initial planning to maintenance.

ZIEHL-ABEGG is also a strong, reliable partner when it comes to retrofitting existing systems and planned system expansions or improvements. We supply technically mature products that are precisely adapted to your requirements. In addition, we convince our customers all over the world with our wide product range, on-site service and the best engineering for all necessary adaptations.

Our product highlights for frequency inverters*

* These ZIEHL-ABEGG products, which are suggested as possible solutions for these applications, are purely informative and serve as a rough guide. Consequently, individual contact with our technical sales experts is necessary and advisable with regard to a specific application so that the individual use can be checked and approved with regard to the explicit conditions.