Product Description
The SoftStarterPro LSRQ900 series is a high-voltage three-phase motor soft starter engineered for 50HP (37kW) AC motors operating on 690V systems. This industrial-grade controller provides reliable motor protection and smooth startup performance for demanding high-voltage applications.
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High Voltage Operation: Designed for 690V three-phase systems
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Optimized Current Rating: 44A capacity for 50HP motor applications
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Advanced Communication: RS485 interface for system integration
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Comprehensive Protection: Reduces inrush current and mechanical stress
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Energy-Saving Design: Bypass operation after startup completion
Applications
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High-voltage industrial pump systems
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Mining and quarry equipment
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Large compressor applications
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Heavy-duty conveyor systems
Note
This soft starter is specifically designed for 690V high-voltage applications. Professional installation and correct parameter configuration are essential for safe and 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
