Design, Manufacturing, Commissioning & Service—Worldwide, including the USA & Central Asia.
* Standardization where appropriate—certification where required.
MKS traces its origins back to BEA, a leading manufacturer of liquid resistance starters founded in 1917.
Three strategic locations, backed by a worldwide network of service partners for rapid response.
A Liquid Resistance Starter (LRS)—also called an electrolytic starter or liquid rheostat—uses an electrolyte tank with electrodes to provide variable resistance during motor start-up. It enables controlled starting of large medium-voltage drives by limiting inrush current and controlling starting torque, particularly for slip-ring (wound-rotor) induction motors used in mills, crushers, conveyors, and shredders, even under weak-grid conditions. The result is smoother acceleration, reduced mechanical stress on the drivetrain, and lower voltage dips on the power supply, making it ideal for heavy-inertia loads and frequent start cycles.
The MFA series of liquid resistance starters impress with their straightforward and sturdy design and high level of costeffectiveness. Their specially-developed and patented blade electrode alignment allows for a very compact design that also simplifies servicing and maintenance. Liquid resistance starters of the MFA 1-5 series are excellently-suited to smaller and medium power range applications from 100 to 10.000 kW.
AFA 25–105 series liquid resistance starters are based on the original 1917 design produced by BEA. Their production and further development was taken up by MKS in 2001. These liquid resistance starters incorporate the classic BEA ring electrode system.
The SFAK series of liquid resistance starters covers a power range from 1,500 to 20,000 kW of engine output. They are usually used as liquid resistance starters for metal shredding drive systems due to their highly dynamic control and positioning characteristics.
We supply the full package: motor, LRS, switchgear and slip resistor. All components are selected and tuned to work seamlessly together — so you get fewer interfaces, clearer responsibility, and a faster path from order to commissioning.
This exceptional position results from our high standards of reliability and quality, our dedication to our customers and confidence in our products. All the more reason for being proud of our extensive reference list. MKS liquid resistance starter and drive systems can be found in more than 100 countries worldwide.
“In our business, equipment has to work — no excuses. The starter system from MKS is solid, dependable, and built for tough conditions. What stood out most was their fast response whenever we had a technical question. A very reliable partner.”
“Good technology, strong support, and a product that does what it promises. Our cooperation with MKS was straightforward and professional. Delivery coordination took slightly longer than expected, but the overall result and product performance were excellent.”
“MKS supported us with exactly the level of technical clarity we needed. Alex personally took the time to understand our operating conditions and guide us toward the right solution. We truly appreciated the personal service, the professional communication, and the reliable performance from day one.”
“What we value about MKS is their practical mindset. They do not just supply a component; they help find the right solution for the application. The quality is convincing, the communication is clear, and the support feels personal.”
“We appreciated the structured and engineering-focused approach of MKS throughout the project. Mr. Krekker was personally involved and gave us clear, practical engineering advice whenever it mattered. That level of personal service made the cooperation smooth and gave us great confidence in the final solution.”
MKS Engineering Inc. was awarded a contract by NASA to supply a liquid resistance starter for a 15,000 HP slip ring motor and replace the existing LRS for the Unitary Plan Wind Tunnel at NASA Ames Research Center.
Following a successful Factory Acceptance Test at the MKS Anlasser- und Elektrotechnik GmbH facility in Jülich, Germany, the MKS Liquid Starter was approved by NASA’s project engineers. The starter was subsequently shipped to NASA Ames Research Center, where it was successfully installed and commissioned.
We are proud to have contributed to this prestigious project and to have supported NASA with a reliable and customized starting solution. Being part of the commissioning team was an honor and a valuable experience for everyone involved.
The most important questions about how an LRS works, where it fits best, and what’s needed for proper sizing.
A Liquid Resistance Starter (LRS)—also called an Electrolytic Starter or Liquid Rheostat—is a motor starting system that uses an electrolyte tank with electrodes to create a variable resistance. It is commonly used to start large motors in a controlled way, helping manage starting current and starting torque, especially on slip ring (wound rotor) induction motors.
An LRS is primarily used with slip ring motors / wound rotor induction motors (WRIM), often in medium-voltageand high-power applications. These motors are typically selected when high starting torque is needed while keeping the starting current and grid impact under control.
An LRS is a strong choice when:
An LRS uses an electrolyte and electrodes to provide a controllable resistance during start-up. As the motor accelerates, the resistance is adjusted to achieve a stable, predictable run-up. Typical systems also include bypass/shorting contactors, as well as level and temperature monitoring for safe operation.
Yes. Recycling and shredder drives often face highly variable loads and require robust, controlled torque behavior. In these applications, dynamic resistance control can help stabilize start-up and operation. For example, solutions like MKS SFAK are typically used in metal recycling / shredder drive systems where demanding conditions require a proven, heavy-duty approach.
Yes. Depending on the application, LRS concepts can be designed for multi-drive setups or parallel motor systems, allowing coordinated start-up behavior and improved handling of load peaks in complex industrial drive trains.
For a fast and accurate pre-selection, it helps to provide:
Modern LRS systems are designed for robust operation with a manageable maintenance routine. Typical checks include electrolyte level, temperature, and conductivity/concentration depending on the system design. In many cases, existing resistance starter systems can also be retrofitted or modernized to extend service life, improve reliability, and better match current operational needs.
Share a few details about your application, and our engineering team will quickly evaluate whether an LRS is the right fit for your use case.
* Request a quick technical assessment with no obligation.
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