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Step by step towards more energy efficiency

Having successfully implemented the EFF1 energy efficiency class with new motors compliant to IE2/IE3 and excelling by a higher drive side effectiveness, the next step is to focus on the drive controllers inside the electrical cabinets.

The challenge with regard to sustainability:

For Grenzebach the use of frequency inverters has been self-evident as they allow energy savings up to 70 % compared to uncontrolled drives. (Source: KEM special edition S2 10.2011)
In addition, the Siemens made SINAMICS Active Line Module (ALM) now allows to buffer excessive motor braking energy in a controlled link circuit instead of „burning" it in the brake resistor. This link circuit, also powered by the ALM, then holds available the power to all drives connected to it.
If more energy is fed back to the link circuit than can be consumed, this recovered energy may even be returned to the customer's power network.
Special-purpose motors not compatible with the SINAMICS ALM control module shall in future have special capacitor modules instead of brake resistors to buffer the brake energy and to make it available again in the acceleration stage.

The initial situation:

Grenzebach not only focus on quality and innovation but also put energy awareness center stage.
As committed handling system supplier to the solar industry and as energy producer with a 470 kW solar power station topping the workshops of the Hamlar headquarters.
Grenzebach strives for advancement and continues improving its products – for which the motor control system is a good example. From the former primitive contactor controls via the controlled drives towards intelligent systems, which even manage energy. Either in form of energy recycling, consequent energy saving or the automatic switch-off of plant sections, which are not used. The times, when current was "burnt" in brake resistors have now significantly changed.

The solution:

Other considerable energy savings can be achieved through a consistently implemented Grenzebach standby concept for machine automation. Unused conveyor elements for example are stopped after a specific idle time to reduce unnecessary idle running and thus to avoid unnecessary energy consumption. Intelligent material flow controllers trigger such sections of plant in time to ensure reliable material conveyance. This approach spares the equipment and saves resources.

The sustainable strengths:

Grenzebach estimate that, depending on the processing line architecture, all of these measures allow to save up to 10 % energy operating costs. Considering that a float glass line has an average connected load of 250 kW and a solar module facility even up to 500 kW, the savings potential is obvious. This new Grenzebach innovation is a real surplus value for the operating company.

The inventors:

Engineering Team of Grenzebach Group

Brief profile of the company:

Name: Grenzebach Maschinenbau GmbH
Headquater: Asbach-Bäumenheim / Hamlar in Bayern
Year of foundation: 1960
Employees: 1500 worldwide / Headquaters Hamlar 500
Solutions: We design, manufacture and deliver fabrication lines and components for the production and processing of flat glass and building panels, for processing of gypsum from raw material to finished plasterboard and special equipment for cutting and drying of veneers. Further spheres of competence are production technology for display glass including clean room applications, technology for thin-film photovoltaic modules, process technology for Concentrated Photovoltaics (CPV) and Concentrated Solar Power (CSP) with Fresnel Mirrors . Grenzebach also provides automation systems for various industries as well as baggage handling equipment for airports and our Grenzebach FlightSim, the new robot-based flight simulator.
Many years of experience in mechanical and electrical plant engineering and sophisticated plant controls, designed within the Grenzebach group, guarantee optimum line functioning. Various process and optical quality inspection systems and a comprehensive spectrum offered by our Competence Center Service complement our product range. We develop, implement and integrate customized solutions for automation and optimization of complex processes. The focus of our solutions is on handling, conveyor technique, flow of material and intralogistics, complemented by high-performance, custom-made controls and components for transport and handling systems in various industries.
Internationality: World-wide with 5 manufacturing locations in the USA, China and Germany and 15 branch offices all around the globe.