VACUTAP VM – the next generation of vacuum on-load tap-changers

Maximizing the efficiency and future prospects of transformers

With a maintenance interval of 300,000 switching operations, the innovative on-load tap-changer VACUTAP® VM enables practically maintenance-free operation in all network applications.
(PresseBox) ( Regensburg, )
Power transformers that are operated for 50 or more years are not unusual these days, in particular in network operation. With the innovative VACUTAP® VM, Maschinenfabrik Reinhausen (MR) is offering a new on-load tap-changer that is ideally suited to this long service life. The retrofitable innovation in vacuum switching technology minimizes maintenance requirements, up to maintenance-free operation. In addition, the VACUTAP® VM’s unique arc control and step protection system protects against damages to the tap-changer and transformer.

The safe and reliable operation of electrical transmission networks places ever increasing demands on voltage and load flow control. At the same time, an increase in efficiency is high on the agenda. Maschinenfabrik Reinhausen GmbH (MR) offers an effective response to these rather contradictory goals with the new VACUTAP® VM. The core field of application of the innovative on-load tap-changer in vacuum switching technology is in transformers from 30 to 200 MVA and the voltage levels of 110 to 230 kV that are typical in the transmission network. However, it can also be used to full potential in arcing furnaces, high-voltage direct-current transmission (HVDC), electrolysis, rectifier and phase shifter applications. What’s more, it is just as effective when used in new transformers as it is in existing oil transformers that have been modernized.

Faster and simple exchange in plug-and-play procedures
The new VACUTAP VM is retrofitable and enables fast, simple change from oil to vacuum switching technology. The connection compatibility of the diverter switch insert to the OILTAP® M/MS ensures that not only the original of one of the most frequently used on-load tap-changers in the world can be exchanged in a plug-and-play procedure, but also similar models based on previous license or non-authorized models can be exchanged in this manner.

Maintenance-free operation in network applications
In the development of the new VACUTAP® VM, the focus is on minimum maintenance requirements and maximum reliability. The results are very impressive – the maintenance interval of 300,000 switching operations, which is both electricity-independent and time-independent, as well as the contact life of 600,000 switching operations, guarantee practically maintenance-free operation of the tap-changer over the entire service time of the transformer in almost all network applications. The lifespan of the diverter switch unit is actually 1.2 million switching operations. In addition, the on-load tap-changer oil is not polluted by the arc extinction as a result of the vacuum switching technology used, which means that neither an oil filter system nor the associated filter changes are required. In addition to a high degree of availability of the transformer, this also leads to lower operating costs.

Interrupter exchange module – faster change of vacuum interrupters
Unlike network operation, up to 200,000 tap-change operations per year are typical in heavy duty applications, such as arc furnaces, HVDC, electrolysis and phase shifters. The interrupter exchange module contributes to reductions in production downtimes due to maintenance when exchanging the vacuum interrupters after 600,000 tap-change operations. This intelligent spare part solution consists of a completely assembled and preconfigured module including a supporting unit, which enables a simple, time-saving change, thus ensuring fastest renewed availability of the transformer.

Arc control system – the operational reliability advantage
Absolutely reliable extinction of the arcing is an essential prerequisite for the trouble-free and damage-free operation of on-load tap-changers and transformers. The arc control in VACUTAP® VM performs this function. In this unrivalled protection system, the vacuum interrupters – which have been specially developed for use in tap-changers – in advanced interrupter technology, a recently patented kinematics of operation and the complete switching sequence have been optimally adjusted to each other. This ensures that the arcing is extinguished even under extreme network conditions.

Step protection – optimized overvoltage protection
The step protection system is also unique in this class. It reliably protects the diverter switch from a short-circuit between taps in the event of overvoltages in the network, due to lightning and switching operations, for example. In contrast to the spark gaps that are normally used for this function, special components from semiconductor technology are used in the step protection system. This results in a lower dispersion of tripping values, so that optimum insulation coordination within the diverter switch is achieved and damage to the insulation is prevented.

Various versions of the new VACUTAP® VM are available and are designed for selected alternative insulation liquids ex works. The new VACUTAP® VM is also suitable for operation in earthquake-prone areas. In addition, the planned ATEX certification will also enable usage in explosive areas. Further information at

VACUTAP®, OILTAP®, arc control system™ and step protection system™ are trademarks of Maschinenfabrik Reinhausen GmbH.

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About Maschinenfabrik Reinhausen GmbH
Maschinenfabrik Reinhausen GmbH (MR) is the largest company in the Reinhausen Group, with regard to both sales and the number of employees. Founded in 1901, MR, with its headquarters in Regensburg and 22 locations around the globe, is the leading global premium manufacturer of on-load tap-changers for regulating power transformers today. Worldwide, more than 50% of current flows through MR tap-changers.

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Maschinenfabrik Reinhausen GmbH, Kerstin Lochner, Falkensteinstraße 8, 93059 Regensburg, Tel: +49 941 4090-5238,,
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