Energy Manager

Mechanical & Plumbing
Intelligent control technology: Rexroth

Dr. Steffen Haack, Bosch Rexroth AGDrive technology offers enormous potential for efficiency improvements in plants and machinery. An integrated cost consideration, however, demands the optimization of life cycle costs, i.e. the expenditure on design and start-up as well as operating, servicing and maintenance costs. “That’s why Rexroth is going one step further and using intelligent control technology and system optimization to push overall energy consumption down systematically and permanently”, says Dr. Steffen Haack, Managing Direct Sales and Service of the Electric Drives and Controls BU of Bosch Rexroth AG, explaining the holistic approach to electric drive and control technology.

In the IndraDrive family and the frequency converters of the IndraDrive Fc series, Rexroth offers the very latest in state-of-the-art energy-efficient automation solutions. System-friendly regenerative power supply units covering the whole spectrum of outputs are available. The modular design of IndraDrive drives facilitates the exchange of oscillating process energy in the drive assembly, allowing the motors to gain braking energy through the exchange in generator operation. A surplus of energy at a particular place is not converted into useless heat, but is instead either fed back into the system or buffered in temporary storage. Add-on capacity modules transfer the buffered recovered energy to a common DC link to which all control units are connected.

The Rexroth IndraDrive Mi compact drive, an innovative motor/control combination, opens up a whole array of other options. These drives reduce cooling demand in the control cabinets and reduce line losses thanks to shorter cable lengths. Cabling can be slashed by up to 85 per cent by linking up to 20 drives to a common power supply. A 50 percent reduction in build space and up to 70 per cent reduction in control cabinet volume, also ensures considerable savings in resources for the manufacture of plant and machinery.

On the motor side, Rexroth achieves efficiencies in excess of 95 per cent from a wide range of synchronous motors with high-energy NdFeB permanent magnets in the rotor. The innovative exciter coil technology with shorter end windings, also contributes to this high efficiency by delivering a significant reduction in resistance losses. Direct drive technology offers further potential energy savings. Rexroth linear and torque motors transmit the movements without the mechanical transmission elements that cause losses.

Energy-efficient drive technology alone far from exhausts the potential for optimization. Rexroth supports the entire process - from project configuration to start-up, with end-to-end engineering tools. The possibilities range from integrated energy consumption recording in drive control units, to control-integrated software tools for cycle time and energy efficiency analysis. The tools analyze every movement and every process step of the machine online. This detailed data forms the basis for optimized motion control that combines high productivity with low energy consumption.

The IndraSize software tool also enables the user to find the optimum motor/drive configuration for his requirements quickly and easily, avoiding unnecessary over dimensioning. The calculation of DC link power ensures that the power requirement of the individual axes is calculated as a function of demand. Optimum motion control through predefined motion modules, and demand-driven control make full use of the energy efficiency of Rexroth’s drive technology.

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