Explore our top-tier collection of high-voltage and efficiency-focused industrial motors, engineered to deliver unparalleled power across complex load applications.
An authoritative engineering breakdown of motor configurations, thermal dynamics, and heavy industrial drive mechanisms.
In heavy industrial processing, starting high-inertia loads is a severe test for electrical grid infrastructure and mechanical drivetrains. A Slip Ring Motor, also known as a wound rotor induction motor, provides an optimal solution. Unlike standard squirrel cage induction motors with short-circuited rotor bars, a slip ring motor features a three-phase wound rotor. The rotor windings are connected to external slip rings and carbon brushes, allowing engineers to insert external resistance into the rotor circuit during start-up.
This design allows for precise control of starting characteristics. Adjusting the external resistance matches the starting torque to the load requirements, achieving up to 250% of full-load starting torque. Crucially, this is accomplished while maintaining the starting current at a low level, typically 1.5 to 2 times the full-load current. In comparison, a squirrel cage motor can draw 6 to 8 times its rated current, potentially causing severe voltage drops in localized power distribution networks. Once the motor reaches operating speed, the external resistors are bypassed, and the slip rings are short-circuited, enabling highly efficient, continuous operation.
Our commitment to engineering excellence is reflected in every structural element of Shandong Sunvim's heavy-duty slip ring motors. We utilize high-grade materials and advanced manufacturing technologies to ensure high reliability in challenging industrial applications:
Industrial operations worldwide face strict energy efficiency requirements and grid-connection limitations. In regions such as the European Union, Australia, and North America, grid codes prohibit large electric machinery from drawing high inrush currents that could destabilize local power systems. In these environments, heavy industrial installations require advanced motor configurations.
Shandong Sunvim Motor Co., Ltd. addresses these requirements by integrating traditional mechanical robustness with modern digital management systems. Our slip ring motor installations are often paired with intelligent Liquid Resistance Starters (LRS) or modern variable frequency drives (VFD) for complex speed control. This enables global heavy industries (such as cement plants in Spain, mining operations in South Africa, or marine yards in Singapore) to balance high starting torque with grid compliance. Our industrial solutions include comprehensive engineering, including starting simulations, torsional vibration analysis, and customized protection relay schemes.
Empowering global industries since 1963 through robust electric motor R&D, precision manufacturing, and professional support.
Backed by the powerful resources of Sunvim Group—a multi-billion RMB conglomerate—Shandong Sunvim Motor Co., Ltd. benefits from strong financial stability and strategic growth. Our expansive facilities house over 400 sets of advanced manufacturing, precision testing, and automated supporting equipment, driving an impressive annual production capacity of up to 3 million kilowatts.
Today, Sunvim Motor has evolved into a premier enterprise seamlessly integrating R&D, world-class manufacturing, global distribution, and dedicated customer service. The SUNVIM brand has earned widespread international recognition. Our high-performance electric motors are trusted by global OEMs and industrial buyers across premier markets, including Germany, Italy, Greece, Spain, Belgium, Denmark, South Africa, Slovakia, Australia, Singapore, Indonesia, Malaysia, and Taiwan.
Our facility is equipped with over 400 sets of advanced testing and production machines, ensuring precision in every manufacturing phase.
From local origins to a global high-tech electric motor manufacturer.
Gaomi Electric Appliance Factory was established. In 1988, renamed as Weifang Electric Machinery Factory.
Mr. Sun, then the factory director, left the Gaomi Electric Appliance Factory and set up Gaomi Towel Factory, the predecessor of Sunvim.
Weifang Electric Machinery Factory was acquired by Sunvim, and Shandong Sunvim Electrical Machinery Co. Ltd. was formally established.
A new factory was completed in the Sunvim Industrial Park, and the company was renamed Shandong Sunvim Motor Co. Ltd. to mark its global modernization.
Over 60 years of production expertise allows us to manufacture durable machinery, supported by generations of engineering knowledge and modern precision technology.
Our manufacturing processes are certified to meet international standards for quality, safety, and reliability across different regions.
ISO9001：2015
CE Mark
UKCA Compliance
UL Standards
SABS Standards
CCS Marine Approval
ABS Classification
DNV Marine Certification
Our heavy-duty induction and slip ring motors provide high reliability and torque across demanding industrial environments.
Integrating digital diagnostic systems and high-efficiency topologies for next-generation industrial drivetrains.
The modernization of heavy industrial slip ring motors relies on predictive maintenance. Shandong Sunvim is developing digital sensor arrays designed for slip ring assemblies. Our future product lines will feature integrated real-time monitoring, including:
Global regulations demand higher efficiency levels across all motor classifications. Sunvim is addressing this by improving the thermal and structural performance of our slip ring and asynchronous motors:
Clear, technical answers to common questions about selection, installation, and preventative maintenance.
While Variable Frequency Drives (VFDs) are effective for speed control, they require a significant capital investment and generate harmonic distortion on the power grid. For applications that require high starting torque under heavy loads (such as large crushers, sag mills, and long conveyor belts), a slip ring motor paired with a Liquid Resistance Starter (LRS) offers a robust, cost-effective solution. This configuration delivers full-load starting torque with low inrush current, avoids high-frequency electrical harmonics, and withstands harsh environmental conditions better than sensitive power electronics.
Regular maintenance is necessary for the slip rings and carbon brushes. Standard maintenance involves inspecting carbon brush wear, verifying that the spring tension is within 1.5 to 2.5 N/cm², and clearing carbon dust with dry, compressed air. Periodically check the surface of the bronze slip ring for pitting, grooving, or eccentricity. Precision manufacturing, such as Sunvim's automatic shaft machining, helps reduce runout and carbon brush wear, which extends service intervals.
Our modular motors are engineered with heavy-duty steel plate structures and customizable enclosures. The YKK series features an air-to-air heat exchanger (IC611 cooling) that isolates the internal motor components from dusty or humid environment air, making it suitable for mines and chemical plants. The YKS series uses water-to-air cooling (IC81W), which provides efficient cooling in high-ambient-temperature environments where water supply is available. The YL series features a compact, open design (IP23) for cleaner, ventilated rooms.
Shandong Sunvim motors are manufactured and certified to international standards, including UL for North America, CE and UKCA for Europe, and SABS for Southern Africa. We design our wound rotors to work with local grid requirements. By engineering custom rotor impedances and matching them with modern starters, we keep startup current below 150% of the nominal current. This avoids voltage drops, satisfying strict utility grid codes globally.
VPI is critical for high-voltage motors (above 3kV). The process places the fully wound stator and rotor under a vacuum, drawing out air and moisture, before injecting solventless epoxy resin under high pressure. This ensures complete resin penetration through the winding insulation. The result is a solid, thermally conductive structure that resists moisture, carbon dust, vibration, and thermal expansion, preventing internal electrical faults.
Yes. Historically, slip ring motors adjusted speed by inserting resistance into the rotor circuit, though this method is less efficient at lower speeds. For modern applications requiring speed regulation, slip ring motors can be paired with a slip energy recovery system (Scherbius drive). This system feeds slip power from the rotor back into the main grid, offering efficient speed control over a limited range without the full expense of a high-power VFD system.
Our engineering team designs custom heavy-duty modular motors, variable frequency drives, and efficiency-focused induction units for complex industrial requirements.
Shandong Sunvim Motor Co., Ltd. supplies customized high-voltage motor topologies, including:
High-output configurations designed to minimize energy consumption in continuous duty cycles.
Offers high reliability without rare-earth permanent magnets, reducing lifecycle maintenance costs.
Custom high-voltage asynchronous motors built for regional utility grids and process control.
Sunvim Motor
