Explore our foundational range of premium asynchronous, explosion-proof, and high-efficiency standard and custom-engineered industrial motors.
Building upon over five decades of electromechanical excellence inherited from European engineering traditions (operating primary production facilities in Gussago (Brescia), Italy and certified global manufacturing hubs), our organization is recognized as a premier OEM/ODM manufacturer of industrial electric motors. We specialize in solving severe heavy-load starting challenges across mining, cement, power generation, and metallurgical sectors.
Every wound rotor motor is tailored to exact load inertias. From frame size adjustments (355mm to 1000mm) to custom shaft extensions and voltage configurations (3.3kV, 6.6kV, 10kV, 11kV, up to 13.8kV), we ensure seamless drop-in replacement or project integration.
Utilizing Class H and Class F thermal insulation systems treated with advanced solventless epoxy resin via VPI processing. Ensures zero partial discharge, high dielectric strength, and immunity against moisture, chemical vapors, and dust accumulation.
Fully compliant with international testing and safety protocols, including IEC 60034 series, ISO 9001 quality management, ATEX/IECEx explosion-proof ratings (OMEX series), and North American NEMA MG-1 specifications.
High voltage wound rotor induction motors—commonly referred to as slip ring motors (IEC frames OMA, OMVK, and OMVKS series)—are engineered specifically for applications demanding maximum starting torque with minimum starting current. Unlike standard squirrel-cage induction motors, which draw starting currents up to 6 to 7 times their full-load current (FLC), slip ring motors regulate current via an external rotor resistance system connected through heavy-duty slip rings and carbon brushes.
During startup, an external resistor—such as a Liquid Resistance Starter (LRS)—is connected to the rotor circuit. This increases the total rotor resistance, shifting the motor's maximum torque point (pull-out torque) to zero speed. As a result, the motor can deliver up to 250% rated torque while limiting inrush current to less than 150-200% FLC. This crucial characteristic prevents severe voltage dips across industrial microgrids and protects utility transformers from thermal stress.
Selecting the optimal drive topology for heavy equipment requires evaluating capital expenditure (CAPEX), operating expenditure (OPEX), environmental resilience, and grid infrastructure limits.
| Evaluation Parameter | Wound Rotor HV Motor + Liquid Starter (LRS) | Squirrel Cage HV Motor + Medium Voltage VFD |
|---|---|---|
| Starting Torque Capability | Exceptional (200% - 250% FLC) at lowest current draw | Moderate to High (150% - 200%), depends on VFD rating |
| Inrush Current Impact | Extremely Low (1.2x - 1.5x Full Load Current) | Very Low (1.0x - 1.2x Full Load Current) |
| Initial Capital Cost (CAPEX) | Substantially Lower (30-40% savings) | High (Expensive MV Inverter transformers & active front-end) |
| Grid Harmonics (THD) | Zero Harmonics Generated (Pure Sine Wave) | Requires Active Harmonic Filters (THD 3% to 8%) |
| Harsh Environment Reliability | Superior; passive external LRS handles dust & ambient heat | Sensitive cleanroom HVAC required for MV VFD electronics |
| Speed Regulation | Fixed speed (or step-wise speed control via rotor resistance) | Continuous variable speed regulation (0-100%) |
As global industrial infrastructure modernizes under carbon neutrality goals and operational efficiency mandates, high voltage wound rotor procurement is shifting rapidly towards smarter, more durable electromechanical solutions.
Next-generation slip ring motors are equipped with integrated Wireless Vibration Monitoring (tri-axial accelerometers), stator winding Pt100 RTD sensors, and brush chamber temperature/humidity detectors. Real-time data streams to cloud dashboards to predict carbon brush wear and rotor ring pitting before catastrophic failures occur.
Plant operators are increasingly mandating automatic motorized brush-lifting and short-circuiting devices. By shorting the rotor windings internally after startup and disengaging brushes from contact, routine maintenance intervals extend from 3,000 hours to over 25,000 hours.
With major mining expansion occurring in South American high-altitude Andes (altitudes >4,000m) and Middle Eastern desert environments, procurement specifications now emphasize ambient temperatures up to +55°C, customized derating insulation, and IP66 dust-proof slip ring housing enclosures.
Our wound rotor high voltage motors are operational across demanding global industrial infrastructure installations.
Conquers immense initial breakaway friction without overheating supply transformers.
Engineered for high shock loads, heavy dust concentrations, and continuous 24/7 duty cycles.
Provides robust thermal reserve and extreme pull-out torque capabilities under sudden load spikes.
Our technical engineering team in Italy and international sales office are prepared to evaluate your project requirements, load calculations, and structural dimensions to deliver optimized high voltage electric motor solutions.
