Power density, productivity, energy efficiency: Servo actuators operate at optimum

By Timo Markert and Siegfried Wallauer, Product Managers at WITTENSTEIN alpha GmbH, Igersheim 

The servo actuators in the premo® series have a modular design principle that enables application focused flexibility, consistent power density and productivity as well as energy efficient downsizing. Many engineering firms also use the cymex® 5 software to optimize the sizing of their individual premo servo actuators – and to unlock ultimate power reserves.

Hardware or software based optimization – which is better? The ideal servo actuator is a dual solution combining the best of both worlds. However, this presupposes an ingenious design principle and a smart sizing tool to match. Whereas premo servo actuators based on a modular system can be scaled according to performance needs, cymex 5 – the multifunctional sizing software – has an “Optimizer” function that allows performance dimensions, and therefore the size of the premo servo actuators, to be individually optimized with regard to productivity or energy efficiency. We refer to this as “efficiency engineering” for the perfect servo drive solution.

Figure: The servo actuators in the premo® series have a modular design principle that enables application focused flexibility, consistent power density and productivity and energy efficient downsizing

premo servo actuators: Individual, flexible configurations

premo, the fully scalable servo actuator platform from WITTENSTEIN alpha, offers top performance from a modular system: servo motors with up to 92 percent efficiency and torsionally rigid precision gearboxes with up to 97 percent efficiency can be configured extremely flexibly to obtain individual servo actuators. The coupling-free design permits a shorter installation length with maximum power density, resulting in the best possible dynamics and precision, even in tight mounting situations. The sizing process takes account of all important drive parameters such as acceleration, speed, positioning accuracy and output geometries as well as additional equipment features or different encoder designs and connectivity options including digital single-cable technology. This forms the basis for WITTENSTEIN alpha’s graduated power categories.

Graduated power categories meet individual automation and integration needs

premo XP Line – the extra class – provides optimal best technological and application performance. With their high maximum output torques of up to 450 Nm and their high tilting rigidity, these servo actuators enable particularly high productivity and versatility in machine tools. Moreover, the fully digital encoder and single-cable technology of this power category is strictly adapted to digital edge computing with Industry 4.0 connectivity. premo XP Line also ships with certified safety: the digital feedback systems have safety certification for applications up to SIL2 as defined by IEC 61508. Machine manufacturers and operators are always on the safe side with premo XP. premo TP Line – the dynamic class – is used, for example, in packaging machines. With its torsional backlash of less than one arcminute combined with high torsional rigidity, it guarantees high precision for positioning tasks where higher dynamics and forces are called for and convinces with optimum overall performance. premo SP Line – the entry level class – offers high application efficiency in regards of output torque and torsional backlash in wood processing machines and handling systems, even in demanding standard applications. Thanks to this perfect scalability, the premo actuator platform meets a wide range of performance, automation and integration needs.

 

Figure: cymex 5 comes with an “Optimizer” function which identifies downsizing potential, especially in machines, axes and drive trains that have already been configured.

 

cymex 5 sizing tool: Optimizing the optimum

With their powerful components and consistently modular concept, premo servo actuators deliver decisive performance in a variety of drive applications. They also convince with exceptional energy efficiency: the elimination of the coupling results in very low mass inertia while the digital single-cable technology reduces material use. No matter which power category is best suited for the specified task – whether in a bending machine, a press feeder, a gantry milling machine or a packaging machine – customized design using the cymex 5 sizing tool can help to unlock additional power reserves and identify downsizing potential. In addition to all components of the modular premo system in a regularly updated database, around 14,000 motor variants from more than 50 manufacturers, over 8000 different gearboxes from WITTENSTEIN alpha and more than 200 combinations of WITTENSTEIN linear systems are stored in the software for sizing servo drive systems. More than 30 years of WITTENSTEIN expertise is made available to users in this way. The graphical user interface can be customized to allow very intuitive use, either when sizing individual servo drives or when defining multiple axes in one project.

When a motor / gearbox unit or an actuator is designed, cymex 5 recommends a drive solution that is tailored for the application – taking in account motion and loads as well as currents, voltages and any other relevant information or requirements. cymex 5 then validates the design of the prototype machine by importing the actual parameters of the movement profile. Extended leeway can be identified in this way, enabling more drive power and higher machine productivity. The transparency of the sizing process and the abstraction of each customer’s individual preferences lay the foundation for an optimum drive solution.

More energy and cost efficiency with premo and cymex 5

cymex 5 also comes with an “Optimizer” function which identifies downsizing potential, especially in machines, axes and drive trains that have already been configured. The software helps to optimize energy consumption by importing a machine’s speed, current and torque profiles and then determining the most energy efficient premo servo actuator for the task at hand. At the same time, it allows existing motor / gearbox units to be replaced with a smaller and more energy efficient premo servo actuator without compromising the machine’s performance. As well as saving installation space, this also reduces the weight of moving axes – and hence the necessary kinetic energy – in moving machine structures. Finally, smaller drives are generally cheaper – and the configuration is more economical overall.

This can be illustrated with the aid of a concrete example, where both the upfront and the operating costs for the drive train were lower as a result of downsizing. With a view to reducing the energy consumption of a delta robot in a packaging machine, the manufacturer was keen to switch to a space saving drive with a smaller servo controller without any loss of productivity. A highly dynamic TP Line servo actuator – which, by eliminating the shaft coupling, achieves the specified rigidity with a more compact design and a lower moment of inertia – was able to deliver equivalent performance to that of a much larger motor offered by a market competitor. Furthermore, power consumption was roughly cut in halve. The customer could thus select both the servo controller and the supply module one size smaller – and profit from substantial savings in terms of purchase and operating costs.

Power density, flexibility, productivity, energy efficiency – premo, the fully scalable servo actuator platform, and cymex 5, the multifunctional sizing software for drive trains, complement one another perfectly and open up new potential for optimizing the hardware and software from both a technical and a commercial perspective.

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