LOAD- AND TEST RESISTORS
Customised solutions – optionally with control system and switchgear
Testing under the use of ohmic loads is an important aspect of the development work of
many industries, schools, universities and research facilities.
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CONTENTS
INTRODUCTION
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DESIGN / CONFIGURATION
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TEST RESISTORS
6
LOAD RESISTORS
10
RLC LOAD UNITS
12
SWITCHGEAR
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OPERATION
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LOAD- AND TEST RESISTORS – FROM THE CONCEPTUAL DESIGN THROUGH TO SERVICING
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INTRODUCTION
Ruhstrat power resistors – Quality since 1888
Ruhstrat has decades of experience in the development and
manufacture of coilware for use in electrical engineering.
Ruhstrat develops and manufactures power resistors for various applications in the power range from 10 W to 5,000 KW.
We offer more than innovative technology, are a reliable partner and support our customers with optimal solutions that are
adapted to their needs.
Ruhstrat is distinguished not only by the wide application range
but mainly by the expertise for the project planning of the many
different resistor systems.
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DESIGN / CONFIGURATION
Whether for test purposes, for testing batteries, transformers,
generators, power generation units and power supply equipment or as load bank for your test facility, Ruhstrat provides you
with an economic solution for every application case.
On request, the load resistors can also be provided with an inductive and/or capacitive component to simulate various loads
with different phase shift angles or specific reactive powers for
generators, switching, contactor and control loads.
Continuous operation outputs of several megawatts as well as
special designs can also be realised. The devices which are
customer-specific in almost all cases can be equipped with any
kind of step circuit, regulation, measurement and control.
We dimension and manufacture the required load and test resistors in accordance with the requirements profile of the respective project as:
 Tube resistor
 Wirewound resistors
 Steel grid resistor
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TEST RESISTORS
For low inductive resistors, the ceramic tubes are bifilar or
sheathed with a cross winding.
In order to be able to realise high outputs for the same voltage with resistance tubes, it is possible to provide the ceramic
tubes with a stepped winding. Advantage: this design is significantly more space-saving.
For tapping different resistance values, the tube resistors can
be provided with regulating clamps or alternatively use variable
resistors.
There are cases where the continuously adjustable resistor is
in an inaccessible location, the resistance must be set very precisely and / or regularly or a specific resistance profile should
be displayed via PLC.
We provide a practical solution for this: the resistor can be adjusted by spindle using a motor (230 V AC or 24 V DC).
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▴ Fig.:
Cross winding
TEST RESISTORS
Ruhstrat tube resistors are available as fixed resistors, rheostats or variable resistors.
Isotan CuNi44 with very small temperature coefficient is used
for the resistor winding.
▴ Fig.:
Stepped winding
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TEST RESISTORS
Wound resistance elements are particularly suitable for the
design of precise load resistors, especially for the test facility
area. Due to the use of regulating clamps, production accuracies of up to 2 % can be achieved!
Resistance round wire or tape made of Isotan CuNi44 with very
small temperature coefficient is used for the resistor winding.
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Our resistance elements are particularly suitable for applications where high resistance accuracy over a wide temperature
range is required.
TEST RESISTORS
No tolerances for the resistance values arise due to the high
resistance accuracy. The resistance elements are used for designing large load resistors.
The resistance elements can be used universally due to their
space-saving construction, flat design and modular structure.
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LOAD RESISTORS
Made of chromium alloyed, heat-resistant steel sheets, the output per steel grid is 500 W.
Various protection types can be realised by installation in an
enclosure that is externally ventilated for increased outputs.
Larger outputs are achieved with the assembly of several steel
grids into one resistor block.
These steel grid resistors make it possible even with smaller
piece counts to provide an optimally adapted solution for many
different applications.
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LOAD RESISTORS
Ruhstrat provides load and test resistors with steel grid resistors in the power range of 500 W – 5,000 kW.
This type of load and test resistors can be adjusted with a resolution of 1 kW using a control panel installed in the cabinet door.
If required, the load banks can be equipped with remote control
(cable lengths up to 1,000 m).
A convenient operating unit with a modern touch panel is also
available in combination with an optional PLC controller.
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RLC LOAD UNITS
In order to test the effect of long cable routes (e.g. for PV systems), voltage peaks (e.g. for CHPs) or off-grid operations (e.g.
wind turbines), it may
ay not only be necessary to use ohmic load
resistors but also to
o plan inductive or capacitive components.
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Ohmic, inductive and capacitive load units are used to simulate
various loads with different phase shift angles.
RLC LOAD UNITS
Ruhstrat provides many different versions of RL or RLC systems
here. Resistance elements, tube resistors or steel grid resistors
are suitable for the realisation of the ohmic load resistors.
We manufacture these inductive components (chokes) with different levels of ohmic resistance.
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SWITCHGEAR
As option for the load and test resistors, we provide complete
switchgear panels with fuses, contactors, measurement, operation and monitoring elements.
These switchgear panels are usually installed in a separate
switch cabinet at the load resistor.
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Many circuits combined with each other of ohmic, inductive or
capacitive components in parallel and in series, star and delta
operation can also be realised.
SWITCHGEAR
If required, high accuracy (up to 0.5 % of the final measurement
value) and flexible adjustment options can be realised with
high quality measuring components.
We work in the resistor area with the Siemens S7 1200 as standard. We are pleased to observe special requirements of our customers.
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OPERATION
Diverse customer requirements can be realised for switching,
regulating and controlling the installed switchgear panels.
The operation can be performed at the unit, on an operating
panel, with a remote control and / or via control room.
The display of current, resistance and voltage values, power,
frequency and overvoltage and undervoltage monitoring are
planned and implemented by us.
Illuminated toggle switches or buttons, circuit breakers, touch
panel or the PC keyboard in the control room represent operating possibilities.
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OPERATION
Analogue or digital measuring instruments, indicator lamps,
built-in multimeter in the front panel, touch panel or monitor in
the control room are provided as display elements.
Profibus or Profinet is used as standard for communication.
However, other communication paths can be used on request
(such as GSM / GPRS).
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CUSTOMISED PRODUCT SOLUTIONS – MADE IN GERMANY
LOAD- AND TEST RESISTORS – FROM THE CONCEPTUAL DESIGN THROUGH TO SERVICING
Ruhstrat is a leading technology supplier with the main focus
on electrical testing, voltage optimizing transformers and power
resistors.
Founded in 1888, the electro-technical company has established itself world-wide as the main supplier of customized solutions.
Our company contributes actively to the Central Association of
the German Electrical and Electronics Industry (ZVEI) and cooperates intensively with universities, technical colleges and research
institutes. This sustainable process of exchange is a constant
source of new impulses in our own research and development.
Since mid-2015, Ruhstrat operates under the name Eisenmann
Thermal Solutions, which is a subsidiary of Eisenmann SE.
Eisenmann is a leading global industrial solutions provider for
surface finishing, material flow automation, environmental engineering and thermal process technology. The company develops and builds custom manufacturing, assembly and logistics
plants that are highly flexible, energy- and resource-efficient.
Today, Eisenmann has a workforce of approximately 3,600
worldwide, with subsidiaries in Europe, the Americas and the
BRIC countries.
>> Facts
 More than 125 years of experience
 Economical, eco-friendly engineering
 Certified according to ISO 9001 since 1993
 Energy-efficient and space-saving design
 Competent project consultation and implementation
for customised solutions – worldwide
 Expert implementation and manufacture of all
equipment based on international standards
 Everything from a single source
 Professional installation and commissioning – worldwide
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Peripheral equipment from in-house development
and production
In-house research and development and close
cooperation with institutes and universities
In-house production and high vertical product
diversification makes us flexible and dynamic
with respect to requests for modifications
In-house electrical and mechanical
design engineering
In-house programming
 Theoretical and practical training of customer personnel
 Extensive after-sales support – also for third-party products
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Maintenance and servicing
Spare parts
System optimisation
Repairs
Modifications / adaptations
Maintenance contracts
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Eisenmann Thermal Solutions GmbH & Co. KG
Leinetal / Auf der Mauer 1, 37120 Bovenden, Germany
Phone: +49 5 51 820 830 – 0, Fax: +49 5 51 820 830 – 50, E-Mail: info@ruhstrat.com
www.ruhstrat.com
2015 © Eisenmann Thermal Solutions GmbH & Co. KG I 11-2015 | 01
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