Technical Solutions and Consultancy for Electric Drive Technology

RPT Ruhstrat Power Technology GmbH

Drive Supply Systems for Motors / Pumps
and Motor, Pump and Transformer Test Rigs

Voltage and Frequency Converters (f.e. 50/60 Hz)

RPT Ruhstrat Power Technology GmbH

Ruhstrat is a leading electrical engineering company and offers over 100 years of experience in transformer technology and develops custom built, high efficiency testing systems. Built into our products is the experience of countless projects realized all over the world in various industries and companies. These include aspects of drive systems, e-mobility, renewable energy, testing facilities, cable testing and heating tests for switchgear.

Ruhstrat, as an internationally established brand for technical testing systems, and TORNATEC, building on years of experience in drive systems, together provide your customers the best outcomes and an accompanying high product quality. We are proud to be able to confirm this level of trust again and again on a daily basis. We always maintain an overview of everything for you and offer you the best possible solution.

The product

The product consists of a custom designed, universal drive supply system (AC) with variable voltage and variable frequency that can be individually dimensioned in regard to both its powerrange and its voltage range to suit particular applications.

This system can be realised not only in a 2Q version but also as a 4Q version, that is, regenerative with active front end (AFE). The AFE can also be expanded by a generator converter connectedto the DC intermediate circuit. Such a design then even allowsregenerative load tests to be performed on electric motors,for which only the power loss of the system from the grid is recorded.

Its combination with transformers enables almost all voltage levels – including medium voltage – to be realised on both the mains side and the output side. In addition to mains filters, the systems also include sinusoidal filters to ensure the voltage quality required by the standards. Both voltage and frequency can be regulated independently of each other.


Typical applications:

  • Voltage and Frequency Converters (f.e. 50/60 Hz)
    for to connect electric devices to different international power grids
  • Electrical power supply systems for
    e.g. electric motors, pumps, fans or transformers
  • Motor testing, also according to IEC 60034
  • Pump testing, also according to EN ISO 9906
  • Transformer testing, also according to IEC 61558


Advantages and Feautures:

  • Mains voltage can almost be selected freely in low-voltage range
  • Output can almost be selected freely by means of transformer
    with/without taps connected incl. medium voltage
  • Output capacity up to 1 MW or greater
  • IT net on output connection side (increased safety)
  • Mains filter
  • Sinusoidal signal through sinusoidal filter
  • Frequency response 20-120 Hz as standard, can be optionally extended
  • Voltage and frequency controlled independently of each other
  • Soft motor start also via U~f curve
  • AFE version with grid compensation (cos phi = 1)
  • In AFE version, mains and motor inverter also with different power allocation
    (the keyword here is motor idling: here the mains inverter dimensioned for
    the effective power can generally be made smaller, and yet larger motors
    can still be started with soft starting and can be run idle)
  • AFE can be optionally extended by adding a generator converter coupled to the
    DC intermediate circuit to perform regenerative motor runs under load with
    generator (4Q)
  • Cooling types: air/water/air conditioning
  • Protection class can be selected to suit requirements
  • Operator interfaces (panel, touchbar) can be selected
  • System integration interfaces can be selected
    (bus systems, analogue and digital I/Os)
  • Custom connection terminal cabinets optional
  • Grid power meter (mains side) optional
  • Integrated voltage/current and power measurement (output side) optional
  • Control system/PLC optional to suit version and degree of automation
  • Router for remote operation optional