Frequency inverter of the latest generation

On the road to a Smart Factory: Frequency inverters by NORD DRIVESYSTEMS

In addition to excellent quality and reliability, drive solutions from NORD DRIVESYSTEMS also feature a great depth of production. In addition to research and development, the drive specialist produces all quality-relevant components in its own facilities. Since 1984, NORD in Aurich, East Frisia, has repeatedly presented significant innovations in drive electronics. The latest highlight is the new NORDAC PRO SK 500P control cabinet inverter, which is currently going into series production.

Whether they are operated in Europe, China or the US, every electronic NORD device was produced in the NORD production plant in Aurich, East Frisia. Since the early 1980s, NORD DRIVESYSTEMS, one of the world’s leading full-range suppliers of electrical, mechanical and electronic drive technology, has had its own electronics production facility in the north-west of Lower Saxony. Over the years, the range of inverters, motor starters and electronics was continually expanded and now includes electronic drive technology up to 160 kW. The production location has also been continually extended. NORD Electronic DRIVESYSTEMS GmbH now employs 130 people and produces more than 125,000 units per year in an area of 5,000 m², with an upward trend.

Technical innovation and evolution

The first frequency inverters were developed and produced in Aurich as early as 1984, at that time in a cooperation between NORD and Enercon. These were analogue devices which were still completely assembled and fitted by hand using THT (Through Hole Technology). With the first digital SK series, produced from 1989 to 1996, it was already possible to offer significantly more compact devices, which were then further refined from 1991 to 1996.

NORD achieved a decisive technological breakthrough: vector control, which was established from 1995 to 2008. A decisive miniaturisation leap followed from 1999 onward with the SK 700E series of inverters. For the first time, their dimensions were those that are now standard for control cabinet inverters.

The first decentralised SK 300E series (2002 – 2013) finally made it possible to mount the inverter directly on the drive and to implement chokes and filters directly on the circuit board in the device to guarantee mains stability. As of 2005, NORD introduced the SK 500E inverters to the market that are still being used in many installations around the world today, and in the following years continued to expand the family of decentralised devices with the SK 200E and SK 1x0E series.

Lean logistics – efficient processes

NORD opened a new chapter in 2016 with the NORDAC LINK decentralised field distributor, for which production capacities were again considerably expanded and reorganised. As with its products, NORD also relies on the latest technologies and the highest quality in production engineering. The automated and flexible production structure in Aurich is state-of-the-art and allows any size of order to be processed in the same manner. Even small batch sizes are possible thanks to flexible production. The NORDAC LINK is produced directly on order by the customer. It is configured in SAP at the final assembly level and then fitted and assembled to the customer’s order. This enables the customer to configure considerably more features. There are also advantages for the production process: The entire production process is controlled via a central order. All data and information are combined online and can be accessed from anywhere at all times. Among other things, placement and test plans are automatically generated from the individual configuration, both in THT production and in the SMD (Surface Mounted Device) area. This is a novel approach to module assembly. Using a QR code on the module, the work plans can be displayed at the individual THT assembly stations. This not only ensures that the right component is placed in the right device, but also allows for greater flexibility. An automated guided vehicle (AGV) system also ensures greater efficiency. The AGV system has been in operation for one year and is responsible for transport from goods receipt to the automatic small parts warehouse. It is planned to use it on more routes.

From printed circuit board to finished field distributor

The efficient process begins as early as at goods receipt. In order to bring as little packaging as possible into production, each package is freed from its outer packaging and transferred to standard crates. The downstream transport is handled by the AGV system. Each item is given a 2D code so that it can be fully tracked until it is used, or inversely from the serial number of the device back to the goods receipt.

The automated small parts warehouse is the hub featuring over 2,000 six-segmented standard crates, and being centrally integrated into the production processes. It serves not only as a warehouse for components, but also for semi-finished products and for linking the production processes. After the SMD department, the assembled modules are returned to the small parts warehouse, from where they are removed for further THT processing. This implements an automatic FIFO procedure (First In – First Out) within the production process.

High performance with maximum flexibility

In SMD production, the eight placement machines place as many as 65,000 components per hour at top speed. In order to ensure fault-free production, all modules are checked using an in-line AOI system (automatic optical inspection) after placement and soldering in a nitrogen atmosphere. Defective modules can thus be intercepted before the next work step and repaired if possible. In THT production, the wired components and other components are added. Here too, soldering is carried out in a nitrogen atmosphere, followed by a 100% functional test of the modules. From THT production, the modules are conveyed to the final assembly Kanban warehouse. As all products are produced directly according to customers’ orders, only a short production lead time and little storage space are required.

Eliminate sources of error, maintain quality standards

To maintain the high quality standard, appropriate quality controls are integrated in Aurich at all production stages. This starts with component checks in goods receipt and continues with the upgrading of the automatic placement machines. The AOI (automatic optical inspection) test in the in-line system is set up so that even the slightest deviations are registered. After THT production, all modules are tested once again. Final testing of the complete devices includes the final inspection of all analogue and digital inputs/outputs as well as a final performance test under full load. All tests are based on the individual configuration. This ensures additional safety – as do the visualisation of the assembly instructions and the laser marking of the devices. This is the only way of guaranteeing the high quality and reliability of NORD products.

Maximum functionality, connectivity and modularity

The most recent innovation leap concerns the control cabinet inverters and is currently going into series production in Aurich just as flexibly: The new NORDAC PRO family of products. This series comes with an impressive number of interfaces for communication and field buses, innovative features as well as plenty of extension possibilities. It can thus be easily integrated into all automation architectures. The new control cabinet inverters have a power range from 0.25 to 5.5 kW and are equally suited for operation with synchronous and asynchronous motors. Various device versions can be optimally allocated to various application requirements. The functions of the modular series can be extended by plug-in control, safety and option modules. Users also benefit from a particularly compact design in book-size format. The slim design saves space in control cabinets and enables side-by-side installation.

Flexible communication options

One highlight is the multi-chip for Industrial Ethernet that enables the use of the major real-time Ethernet standards via a single interface. Whether for ProfiNet, EtherNET IP or EtherCAT, the required protocol can be easily set by means of parameters. In conjunction with a USB connection (type C) for parameter setting even without external power supply (parameter loading in the box), an SD card slot for parameter data storage and transfer, a CANopen interface and the RS485 serial interface, the new control cabinet inverter is an absolute communications professional. It is available as a machine inverter (SK 500P) with fewer interfaces and as a fully equipped application inverter (SK 530P and SK 550P). The dimensions of the smallest size are just 65 mm wide, 135 mm deep and 200 mm high. This compact design was made possible by using new technical processes and by the unbroken trend towards miniaturisation in the electronics industry, which is making components such as capacitors, IGBT power modules, memory chips and processors ever smaller and more powerful. This opens up completely new technical possibilities in terms of performance, range of functions and safety. The heat sinks were also optimised in terms of airflow and heat dissipation so that they can be as small as possible. The inverters in sizes 1 and 2 are also implemented as a single-board solution: All electronic components are placed on a single circuit board. This not only makes the devices more compact, but also more efficient. At the same time, the overall concept has been revised, so that the SK 500P inverter series from NORD DRIVESYSTEMS provides a new future-proof platform which promises many years of power and performance.

Company background

With more than 4,000 employees, NORD DRIVESYSTEMS has developed, produced and sold drive technology since 1965, and is one of the leading global full-service providers in the industry. In addition to standard drives, NORD delivers application-specific concepts and solutions for special requirements such as energy-saving drives or explosion-protected systems. In the 2019 financial year, annual sales amounted to €750 million. NORD now has subsidiaries and sales partners in 98 countries worldwide. The extensive sales and service network guarantees optimal availability, enabling short delivery times and customer-oriented service. NORD produces a very diverse range of drives for torques from 10 Nm up to over 250 kNm, supplies electric motors in the power range of 0.12 kW to 1,000 kW, and supplies the required power electronics with frequency inverters of up to 160 kW. Inverter solutions are available for conventional control cabinet installations as well as for decentralised, fully integrated drive units.

https://www.nord.com