Control technology at Ziehl-Abegg AG
In 1980 Ziehl-Abegg started its activities in the control technology sector.
ZETADYN and ZETAREC were created as system names, and as of 1982 they were joined by ZETAVENT. The three control systems were based on the principle of voltage regulation. The ZETADYN control system was used to equip elevators and rack serving units, ZETAREC was used for cranes and ZETAVENT for ventilation systems.
ZETAREC was, for example, deployed in the core research center in Karlsruhe, where a 50-ton load had to be positioned with absolute accuracy. During the startup years the controllers were bought in, with Ziehl-Abegg being responsible for the technical consulting, initial startup and service. 1982 saw the startup of the first in-house developments, which resulted in 1985 in the first series production of a single-phase voltage regulator. This in turn resulted relatively quickly in a series of different models, and from 1987 onwards the range of three-phase voltage regulation units was introduced.
In the area of frequency inverters, 1984 saw the start of the first customer-specific developments. The first project was for the Kassel streetcar: A fan which cooled the braking resistances of the streetcar lines was controlled by a frequency inverter. After this, various track applications were used in which some output filters were also deployed. Continuation of this development resulted in the launch of the "Fcontrol" frequency inverter product range from 2001 onwards.
Mains powered EC-drives (EC: Electronically commutated direct-current motor) have been used by Ziehl-Abegg since 1985. The first mass-production products were delivered in 1991. Initially these were deployed primarily in digital telephone exchanges (DIV), being set up at the time by the German Federal Postal Administration (Telekom predecessor). The call for tenders for the DIV air-conditioning units evaluated not only the procurement price but also the energy costs over 10 years. The outstanding efficiency of the EC-fans from Ziehl-Abegg resulted in them being deployed by all of the renowned DIV equipment suppliers. In the first EC applications the motor and the electronics were separate units. From 1998 on, Ziehl-Abegg supplied the first axial fans from the FH035-065 and FC040-063 model range with an integrated EC controller. These fans from the "ETAvent" model range were mainly deployed in the fields of thermodynamics and agriculture. The product range was extended from 2000 onwards by the introduction of three-blade agricultural fans, namely models FE071 and FE091.
Because the range of controllers available from Ziehl-Abegg AG – often for specific customer applications – has, in a manner of speaking, "grown historically", the outlay for support in the technical departments and documentation has constantly increased. The production and customer support areas also demonstrated that the great variety of end products, assemblies and parts was becoming increasingly more difficult to control.
As from 2002 greater efforts were made to ensure that the design for operation and electrical connection of all the unit series was – as far as possible - identical. As a result, contemporary Ziehl-Abegg controllers were standardized to the extent that, the underlying technical principle (phase shift, frequency converter, EC-controller) plays practically no role at all for operators.
The positive resonance exhibited by customers demonstrated that Ziehl-Abegg was on the right track with its control-specific product range.
During the initial development years, sales, support and service were primary considerations in the control technology sector. Production of the control technology division was initially restricted to controller assembly and final inspection. Indeed. as early as 1983, a wave soldering system was available, but this was only used to solder printed circuit boards for "transformer control units". These printed circuit boards had very little in common with electronics, but rather they were mainly intended to simplify the circuit layout for these units, which were also known as "transformer actuators".
Right up to the start of the nineties. assembled printed circuit boards for electronic controllers were purchased from external suppliers.
During this period Ziehl-Abegg recognized that control technology products would be an extremely important and trend-setting supplement to the previous core products of "motors" and "fans". The control technology sector was then accordingly promoted and expanded.
In the production area, 1992 saw the start – in contrast to the trend among many other companies – of an in-house assembly process for printed circuit boards for the company’s own product range. Whereas, until then, the wave soldering machine, which was now 10 years old, had only been used once a week, now it was running at full capacity almost every day. In 1998 a production line for manual assembly with six workplaces and an automatic wave soldering machine was installed. This in turn served to improve quality, boosted efficiency and – through the use of low particle "no-clean fluxing agents" – the environment also benefited.
2001 was an important year for production in the control technology division. The relocation of part of the motor winding room to another site, freed-up space in Künzelsau. The control technology sector urgently required this space for an extension of its production capacity. The "printed circuit board production" department was taken out of the assembly department and set up as a separate department. The manual assembly capacity was able to be significantly increased from six to ten workplaces.
However, the most important step during this year was the move by Ziehl-Abegg into in-house SMD-assembly. The decisive reason for this lay in the fact that the procurement of externally produced printed circuit boards starting with inquiries to external assemblers and on to series production, was simply taking too long – several months - and thus was no longer market-specific. With its own SMD assembly system, the final gap in in-house production was closed so that it was then possible to supply a new product - following approval by the development department - within an extremely short period of time.
The production facilities for SMD assembly are designed for the large model variance of the Ziehl-Abegg controllers: A pick-and-place machine from the MIMOT company with its single-feeder design is extremely setup friendly, a vapor-phase soldering system requires very few soldering programs and was also designed at the procurement phase for subsequent unleaded soldering processes.
Functional test systems were available since the start of the nineties for the testing of populated assemblies, with which program-assisted PCB testing could be conducted in a vacuum adapter. In the meantime, the equipment has been expanded by several multifunction test systems, which enable both the individual components on a PCB ("in-circuit test") and the functions of the assemblies to be tested. The resulting high fault detection rate contributes in a major way to the high quality standard associated with Ziehl-Abegg controllers.
A major challenge for any electronic production process was the EU Directive 2002/95/EG "…for restricting the use of certain hazardous materials in electrical and electronic equipment" – better known under the term "RoHS". This directive was adopted into German national law with the "ElektroG" in March 2005.
Although products from Ziehl-Abegg do not fall under the categories of electrical equipment encompassed by this Act because of their application fields, Ziehl-Abegg AG viewed it as a matter of course to banish the substances that would be hazardous to the environment as listed in the RoHS Directive from its products – even without any statutory obligation – by no later than the deadline of 1st July 2006.
The most significant challenge with regard to control technology production was the conversion from well-established tin-lead alloy soldering processes that had been used for decades to alloys without lead. Due to the fact that years prior to the passing of the "ElektroG" Act this very subject had already been under consideration, it was then possible in 2005, i.e. the year prior to the statutory deadline, to changeover completely to unleaded soldering.
The first step in May 2005 saw the SMD production change to "unleaded". That was relatively simple to do, as in principle only one unleaded soldering paste had to be used, whereby the temperature in the vapor-phase soldering process had to be increased from 200°C to 230°C. The temperature stress for components and printed circuit boards for this process is considerably lower than for the conventional reflow soldering method, in which soldering temperatures of between 250 and 260°C are required.
The outlay for unleaded manual population was greater. The conversion to unleaded solder for the wave soldering system which had only been procured in 1998 would only have been possible with an immense outlay and lengthy loss of production. This is why a new soldering system was procured, which, following an extended test operation, was able to enter series production as of October 2005.
Therefore, all electronic assemblies manufactured by Ziehl-Abegg since October 2005 have been assembled without any lead. The time up to the 1st July deadline was able to be used to sell off the assemblies and end products still in the warehouse that did not comply with RoHS.
The level of proficiency attained during the course of the past twenty-five years with regard to development and production of controllers has enabled Ziehl-Abegg AG
In the area of frequency inverters, 1984 saw the start of the first customer-specific developments. The first project was for the Kassel streetcar: A fan which cooled the braking resistances of the streetcar lines was controlled by a frequency inverter. After this, various track applications were used in which some output filters were also deployed. Continuation of this development resulted in the launch of the "Fcontrol" frequency inverter product range from 2001 onwards.
A major challenge for any electronic production process was the EU Directive 2002/95/EG "…for restricting the use of certain hazardous materials in electrical and electronic equipment" – better known under the term "RoHS". This directive was adopted into German national law with the "ElektroG" in March 2005. 
