Product Description
The SoftStarterPro LSRQ900 series is a versatile three-phase motor soft starter engineered for 25HP (18.5kW) AC motors operating on 380V-420V industrial power systems. With wide voltage compatibility and advanced control features, it provides reliable motor protection and smooth startup performance.
-
Wide Voltage Compatibility: Suitable for 380V, 400V, and 420V three-phase systems
-
Optimized Current Rating: 36A capacity for 25HP motor applications
-
Comprehensive Motor Protection: Reduces startup current surge and mechanical stress
-
Advanced Communication: RS485 interface and 4-20mA analog control
-
Energy-Saving Bypass: Automatic switch to bypass mode after startup completion
Applications
-
Industrial pump and compressor systems
-
Fan and blower motor control
-
Conveyor and material handling equipment
-
Machinery in regions with 380V-420V power standards
Note
This soft starter requires proper configuration for specific motor parameters. Ensure correct installation and voltage settings match your local power supply 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
