Excerpt:
The low voltage solid-state soft starter cabinet is designed to provide smooth motor starting and protect low-voltage motors from inrush current and mechanical stress. It ensures reliable, energy-efficient operation and prolongs motor lifespan in industrial applications.
Low-Voltage Solid-State Soft Starter Cabinet: Complete Intelligent Motor Starting & Control Solution
01 Product Overview: Innovative Motor Starting Technology
The Low-Voltage Solid-State Soft Starter Cabinet is an advanced motor starting device using power electronics and intelligent microprocessor control, designed for three-phase asynchronous motors. By applying thyristor (SCR) phase control, it precisely regulates motor voltage and current, addressing issues of high inrush currents, mechanical stress, and energy waste associated with DOL, Y-Δ, and autotransformer start methods.
Simo Motor’s low-voltage soft starter integrates digital control, soft start/stop, real-time monitoring, and comprehensive motor protection, making it a key solution for modern industrial automation in sectors like power, metallurgy, mining, chemical, construction, and water treatment.

02 Core Technology & Structural Design
1. Intelligent Control Principle
- Microprocessor-Based Control (CPU): Controls SCR firing angles via optically isolated triggers.
- Soft Start Modes: Includes constant-current start, voltage ramp start, and flexible ramp profiles.
- Automatic Bypass: When the motor reaches rated speed, the bypass contactor engages for full-voltage efficient operation.
- Precision Control: Smooth voltage and torque ramp reduces grid impact and mechanical stress.
2. Precision Structure & Safety
- Modular Components: SCR modules, motor protection modules, communication interface, and control transformer for easy maintenance and expansion.
- Three-Chamber Isolation: Power module, control relay chamber, and main circuit connection chamber isolated to enhance anti-interference.
- Multiple Protection Mechanisms: RC snubber, static/dynamic voltage balancing, overload protection (125% rated continuous, 500% for 60s).
- Optimized Cooling: ≤75kW natural air cooling; ≥90kW forced air cooling for stable operation.
03 Core Functions & Advantages
1. Multi-Mode Start & Stop
- Current-Limited Start: Limits inrush to 100–500% rated current, reducing voltage dips and distribution upgrade costs.
- Voltage Ramp Control: Adjustable initial torque 30–90% of rated voltage, smooth acceleration for various loads.
- Pulse Kick Start: Overcomes static friction for heavy loads.
- Soft Stop: Gradually reduces voltage to prevent water hammer; adjustable 0–60s stop time.
2. Intelligent Diagnostics & Communication
- HMI Interface: LCD and keyboard for monitoring and parameter configuration.
- Remote Monitoring: RS-485 interface, supports Modbus for DCS integration.
- Fault Recording: Logs recent faults for quick diagnostics; includes over/under voltage, phase loss, overcurrent protection.
- Analog Output: 4–20mA for process control integration.
3. Efficiency & Cost Advantages
- Reduced Inrush Current: Protects the grid and minimizes mechanical stress.
- Extended Motor Life: Lowers vibration and wear, reduces maintenance and replacement costs.
- Energy Saving: Avoids unnecessary power spikes, optimizing operational efficiency.
04 Technical Specifications
| Parameter | Specification |
|---|---|
| Rated Voltage | AC 380V (-20%, +15%) |
| Control Voltage | AC 220V ±10% |
| Rated Current | Up to 630A |
| Applicable Motor | 30–630kW squirrel-cage asynchronous motors |
| Start Modes | Voltage ramp, current-limited, pulse kick, constant voltage, jog |
| Protection Level | IP20 (customizable) |
| Cooling Method | ≤75kW natural air, ≥90kW forced air |
| Operating Temperature | -25℃ ~ +40℃ |
| Humidity | ≤95%, non-condensing |
05 Application Scenarios & Industry Solutions
1. Typical Load Applications
- Pumps: High-head, circulation, or supply pumps; soft stop prevents water hammer.
- Fans & Compressors: Heavy-load start mode protects high-inertia loads.
- Heavy Machinery: Ball mills, crushers, conveyors, mixers; reduces mechanical shock.
- Conveyors: Smooth start avoids material spillage.
2. Industry Applications
- Power: Protects auxiliary motors for stable production.
- Cement: Soft start for mills, fans, crushers under frequent stop-start conditions.
- Chemical: Pumps, compressors, fans receive reliable start protection.
- Metallurgy: Protects rolling mill and fan motors.
- Mining: Ensures safe operation of hoists, pumps, and ventilation systems.
06 Selection & Installation Guide
1. Key Selection Factors
- Motor parameters: voltage, power, starting torque, load type.
- Environment: altitude, temperature, protection, and explosion-proof requirements.
- Function: communication protocols, soft stop, remote control.
- Load type: standard or heavy load; starting frequency (≤15 starts per hour recommended).
2. Installation & Maintenance
- Auxiliary Devices: Requires bypass contactor and motor protection devices.
- Environment: Fire/explosion-free, non-corrosive, low dust, vibration <0.5G.
- Cooling: Ensure adequate ventilation; forced-air models require operational fans.
- Maintenance: Periodically check RC snubbers, SCR modules, trigger circuits, and clean airways.
07 Core Advantages of Simo Low-Voltage Soft Starter
- Certified Quality: ISO9001 ensures stable and reliable product quality.
- Reliable Design: High-quality components, tested for thermal cycling and vibration.
- Intelligent Protection: Comprehensive protection for phase loss, overload, overcurrent, overheating, and start time limits.
- Flexible Configuration: Adjustable output to match actual load when nominal power exceeds load requirements.
- Full Lifecycle Service: One-stop support from design to training, with lifetime upgrade options.
Simo Low-Voltage Solid-State Soft Starter Cabinet is an ideal replacement for traditional motor starters, providing advanced control, reliable protection, energy efficiency, and smart operation. It enables industrial users to achieve intelligent, safe, and cost-effective motor starting, increasing productivity and operational reliability.





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