Product Description
The SoftStarterPro LSRQ900 series is an advanced three-phase motor soft starter that provides smooth acceleration for AC motors up to 15HP (11kW). With intelligent control features and robust construction, it protects motors and mechanical systems during startup.
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Dual Voltage Operation: Compatible with 440V and 460V three-phase systems
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Motor Protection: Reduces current surge and mechanical stress during startup
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Advanced Communication: RS485 interface and 4-20mA analog control
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Bypass Operation: Efficient running after startup completion
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Smooth Acceleration: Controlled torque ramp-up for various loads
Applications
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Three-phase AC motor startup control
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Industrial pump and fan systems
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Conveyor belt drives
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Compressor motor control
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Industrial machinery acceleration control
Note
This soft starter must be used with compatible AC motors and properly configured for specific application requirements. Ensure correct motor parameters are set for optimal performance and protection.
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
