Made for generations.
    on-load tap changers from MR.

    The world's oldest MR on-load tap-changer has been in service for 65 years

    It's official: The oldest tap changer still in service anywhere in the world can be found in the UNIPER oil-fired power station in Ingolstadt. It is an OILTAP® DIII constructed in 1950. This is a great demonstration of the unique reliability and longevity of our products. Its long life is also the result of regular maintenance. We would like to take this opportunity to thank all our customers around the globe for sending in numerous photos and e-mails.


    90 years ago, Dr. Bernhard Jansen had a vision that would revolutionize the way in which we supply energy. The ingenious engineer invented a control mechanism which allowed electrical voltage to be controlled while under load and without any interruptions. When he applied for a patent in 1925, it was the start of a new era, not just in energy management, but also in the history of our company. Since then MR has not only been influential in shaping the industry but has also set new standards by constantly further developing its products. Today, 90 years later, MR is still owned by the founding families, Scheubeck and Jansen, and has proven its independence and self-reliance over the generations.
    More about Dr. Bernhard Jansen

    Even while studying for his doctorate, Dr. Dieter Dohnal, the current Executive Director Technology of Maschinenfabrik Reinhausen (MR), was looking into vacuum technology for the high-voltage sector. After joining MR in 1981, he began investigating alternatives to oil-based switching technology. He needed an alternative that would meet very stringent service-life, reliability, and economic viability requirements. He considered and rejected a large number of options. In 1986 Dr. Dohnal was appointed to the US-based joint venture between MR and Westinghouse Electric Corp. and on 1 January 1987 became the Engineering Manager of Reinhausen Manufacturing Inc., in those days still located in Alamo/Tennessee/USA. Working from the US, he stepped up work on vacuum-based switching technology together with two technical designers in Regensburg.

    1990 was a crucial year. The takeover of the Westinghouse tap-changer production was successful and further product developments were launched. For example, the first VACUTAP® with the designation RMV I, the first MR reactor-type tap-changer with vacuum-based switching technology, developed and industrialized in Regensburg for production in the USA. Just one year later the decision was made to switch from oil-based to vacuum-based switching technology for on-load tap-changers. A milestone in the company's history.

    Customer confidence is of major significance for a leap in technology on this scale. On-load tap-changers are the only moving part in a transformer and are highly relevant to operation. Reliability and safety are and have always been the number one priority for customers and MR. Customers were very quickly won over by the benefits of vacuum-based switching technology and success wasn't long in coming. Over time, the technology was further developed and MR now supplies a complete range of VACUTAP products for all applications.

    On-load tap-changers from MR have been in use around the world for almost a century. Having sold 250,000 units, we have the largest installed base and also the most operating experience, which we continuously incorporate into the further development of our products and services. Around 80 percent of our tap-changers are still in use, providing the best possible evidence of their extraordinary quality and unique reliability.

    The robust TAPMOTION® ED motor-drive unit is the result of our decades of experience.
    With 100,000 units supplied since its launch in 1997, the TAPMOTION® ED drive is synonymous with superlative safety and reliability. Tried and tested components, modular design, and the quiet transmission gear with a maintenance-free, belt-type transmission gear guarantee maximum availability for decades. On request, the drive is supplied ex factory with the new ISM automation platform. This records, stores, and analyzes the most important transformer operating data, making condition-based maintenance possible. Other functions, such as voltage regulation and cooling system control, can be integrated as options so that even complex and individual automation and monitoring tasks can be handled.

    For extreme long-term availability:
    On-load tap-changer maintenance from MR

    Our technical expertise in both development and maintenance is unique and unrivaled the world over. The on-load tap-changers we have maintained are still running perfectly even decades later. Regular maintenance ensures extreme long-term availability. This also includes genuine spare parts, which we can even provide for old makes and other manufacturers. On-load tap-changers that are maintained regularly and on time will last for the lifetime of the transformer.