Product Description
The SoftStarterPro LSRQ900 series is an industrial-grade three-phase motor soft starter specifically engineered for 25HP (18.5kW) AC motors operating on 480V-500V systems. With advanced control features and robust protection mechanisms, it delivers reliable performance and extends motor service life.
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Dual Voltage Compatibility: Optimized for 480V and 500V three-phase systems
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Enhanced Current Rating: 31A capacity for 25HP motor applications
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Advanced Motor Protection: Reduces inrush current and mechanical stress during startup
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Smart Communication Interface: RS485 and 4-20mA analog control capabilities
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Energy-Efficient Operation: Automatic bypass mode activation after successful startup
Applications
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Industrial pumping systems
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HVAC and ventilation equipment
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Compressor and refrigeration units
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Material handling conveyors
Note
This soft starter requires professional installation and proper configuration according to specific motor parameters. Ensure correct voltage settings match your power supply system for optimal performance.
Advanced Specifications
| Parameter |
Specification |
| Starter Type |
Bypass Type |
| Starting Method |
Current Limiting / Voltage Ramp / Surge Voltage Ramp |
| Stop Method |
Free Stop / Soft Stop |
| Current Limit Range |
50% ~ 600% adjustable |
| Voltage Ramp Time |
1s ~ 120s adjustable |
| Soft Stop Time |
1s ~ 60s adjustable |
| Cooling Method |
Natural Cooling |
| Communication |
RS485 Modbus RTU |
| Protection Class |
IP20 |
| Ambient Temperature |
-25°C ~ +40°C |
| Installation |
Wall-mounted |
Comprehensive Motor Protection Functions
| Protection |
Description |
| Overload |
Adjustable grade 0–30, startup & running |
| Over/Under Voltage |
Trips at abnormal supply voltage |
| Phase Loss |
Input & output phase loss detection |
| Phase Imbalance |
Adjustable threshold, auto shutdown |
| Underload |
Prevents pump dry-running & cavitation |
| Overtemperature |
Internal thermal monitoring |
| SCR Fault |
Thyristor breakdown detection |
| Fault Memory |
Last 12 fault records stored |
Frequently Asked Questions
Q: What is the difference between bypass type and online type? Which should I choose?
A: Bypass type switches to a bypass contactor after startup, eliminating SCR heat loss — lower energy consumption and easier wiring. Online type keeps the SCR active during running. We recommend bypass type for most applications, especially if you want simpler installation and lower running costs.
Q: How do I select the right soft starter size for my motor?
A: General rule:
- Heavy-duty loads (compressors, conveyors): choose 2 sizes up from motor rating
- Light-duty loads (fans, pumps): choose 1 size up or match motor rating
👉 For detailed selection guidance, refer to our soft-starter-selection-guide
Q: Can a soft starter control motor speed?
A: No. A soft starter only controls startup and stop — it cannot vary speed during running. If you need variable speed control, please choose a VFD (Variable Frequency Drive) instead.
Q: Is it compatible with synchronous motors?
A: No. This soft starter is designed for squirrel cage induction motors (asynchronous) only. It is not compatible with synchronous motors or wound rotor (slip ring) motors.
📄 Download Manual LSRQ900 Series Soft Starter Manual
