High-efficiency, explosion-proof, and custom high-voltage motor lineups engineered for extreme industrial environments.
In large-scale medium and low-voltage heavy-duty power systems, managing transient mechanical loads and inrush currents is one of the key engineering challenges. Direct-on-Line (DOL) starting of high-capacity three-phase asynchronous motors can pull up to 8 times the nominal current from the power grid. This inrush current often leads to voltage dips in plant grids, causes severe electromagnetic stress in the stator windings, and induces shock loads in gearboxes, fans, and coupling components.
Custom Star-Delta (Wye-Delta) starting configurations provide a balanced, cost-effective solution for reducing startup current draw. By utilizing six winding terminals, the motor stator windings are initially configured in a Star (Y) connection during startup. In this mode, the phase voltage across each motor winding is reduced to 57.7% (1/√3) of the line voltage, which drops the startup torque and current to approximately 33.3% (1/3) of their full DOL values. Once the rotor accelerates to near-nominal operational speed, the terminal contacts switch to a Delta (Δ) configuration, restoring full rated voltage and torque characteristics.
Xi'an Lite SIMO Motor Co., Ltd. provides robust, custom-engineered three-phase motors optimized specifically for Star-Delta switching operations, ensuring reliable insulation, durable winding construction, and long service life under high-frequency switching cycles.
Founded in 1955, Xi'an Lite SIMO Motor Co., Ltd. (often referred to as LITESIMO or SIMO Motor) has established itself as an elite pioneer in the Chinese mechanical and electrical machinery manufacturing sector. Over more than 60 years of dedicated development, SIMO has grown into a comprehensive manufacturing and service supplier, integrating motor design, high-precision machining, custom mold design, structured assembly, and state-of-the-art testing systems.
With a registered capital of 21.5 million RMB and 3 specialized manufacturing factories plus one subsidiary factory, SIMO controls fixed assets valued at over 380 million RMB. Our production infrastructure houses more than 1,172 sets of advanced equipment, enabling high-precision machining, automated coil winding, and vacuum pressure impregnation (VPI). Our workforce features over 1,200 employees, including a core engineering force of 260+ technical engineers, 21 senior engineers, and 15 state-level expert engineers, driving our continuous technological innovation.
Technical comparison of Star-Delta starters against other common industry technologies for three-phase asynchronous motors.
| Performance Indicator | Direct-on-Line (DOL) | Star-Delta Starter (Wye-Delta) | Solid-State Soft Starter | Variable Frequency Drive (VFD) |
|---|---|---|---|---|
| Inrush Current Draw | Extreme (600% - 800% of nominal) | Moderate (200% - 250% of nominal) | Controlled (150% - 400% variable) | Low (100% - 150% maximum) |
| Initial Starting Torque | High (150% - 250% rated) | Reduced (approx. 33% of rated) | Adjustable (30% - 80% range) | Fully Adjustable (up to 150%) |
| Mechanical Wear Profile | Severe shock loads on shafts | Moderate stress during transition | Smooth, linear acceleration | Minimal mechanical wear |
| Harmonic Grid Distortion | None | None | Minimal during starting phase | High (Requires filtering / active front-end) |
| Capital Expenditure (CapEx) | Very Low | Low (Relays, contactors, 6-wire motor) | Medium | High |
| Physical Footprint & Complexity | Compact, simple setup | Moderate panel space required | Compact electronic panel | Large size, cooling required |
How global sectors optimize their processes using custom Star-Delta three-phase motors built for extreme demands.
Mining operations rely on flameproof systems. Our China YBK3 series flameproof motors operate safely in coal mines with high methane concentrations, using Star-Delta starting configurations to prevent grid collapse in remote areas where line capacity is restricted.
In hazardous chemical plants, the OEM YBX3 and YBX4 explosion-proof asynchronous motors provide flameproof protection. By using Star-Delta configurations, starting currents are limited to prevent overheating of terminal connectors and cables, ensuring safety.
Large municipal pumping stations use high-efficiency systems. Large YKK and YKS high-voltage three-phase motors utilize Star-Delta startup to prevent water hammer effects in pipelines during startup phases, reducing mechanical shock across the system.
The global industrial sector is undergoing a rapid transition toward high energy efficiency and integrated digital intelligence. At Xi'an Lite SIMO Motor Co., Ltd., we are designing our three-phase motors to exceed the IEC 60034-30 standard for IE3, IE4, and IE5 energy classes.
Our technology roadmap focuses on three main developments:
Over 60 years of technical progress in heavy industrial machinery, motors, and high-voltage design.
SIMO's R&D and manufacturing encompass a broad spectrum of electric motor classes. Our design portfolio spans 34 major series, over 1,800 varieties, and more than 19,500 distinct specifications. The power capacity ranges from 0.35kW up to 25,000kW.
Key motor products include:
SIMO products undergo strict testing to meet international safety and performance criteria.
Technical answers to key questions about Star-Delta three-phase motors and startup configurations.
Heavy industrial synchronous, DC, and variable speed motors engineered for processing mills, extruders, and heavy mining machinery.
Lite Simo
