CCC certified
Three starting modes: constant current, voltage ramp, pulse kick-start
LED operating panel
KULUN / Soft Starter
MS21-M Soft Starter, Bypass Type, 5.5–630 kW
KULUN MS21-M: standard bypass-type low-voltage AC motor soft starter with microprocessor control, 5.5-630 kW for pumps, fans and crushers.
Mains Voltage RangeAC 110–440 V (mains)
Matched Motor Power5.5–630 kW
Features
Specifications
Input | Mains supply | AC 110–440 V, 45–65 Hz |
Control supply | AC 220 V, 50/60 Hz | |
Output | Output type | Bypass type; external bypass contactor required |
Rated range | 5.5–630 kW | |
Operating characteristics | Starting modes | Constant current, voltage ramp, pulse kick-start |
Duty | Short-time duty, max. 10 starts per hour | |
Key features | Stopping modes | Soft stop, coast stop |
Start / stop time | 1–120 s | |
On-line monitoring | Not supported | |
Inputs | 4 digital inputs (run, stop, jog, programmable) | |
Outputs | 2 relay outputs (fault, bypass), NO contact, AC 240 V/3 A, DC 24 V/5 A | |
Communication | Modbus RTU | |
Current transformers | 3 built in | |
Protection rating | IP20 | |
Protection | Mains fault | Protection on mains frequency out of range, undervoltage or input phase loss |
Phase imbalance | Protection when load current exceeds the imbalance threshold | |
Overheating | Protection when thyristor temperature > 85 °C | |
Overcurrent | Protection when output current reaches the set multiple | |
Motor phase loss | Protection when load current falls below the threshold setting |
Typical Applications
The MS21-M is a standard bypass-type low-voltage AC motor soft starter, 5.5–630 kW, with constant-current, voltage-ramp and pulse kick-start modes. Typical applications:
Pumps and fans
Standard three-phase motor starts where soft stop or coast stop is sufficient, with adjustable 1–120 s ramp and up to 10 starts per hour.
Compressors
Constant-current or voltage-ramp starting limits inrush on compressor drives; an external bypass contactor is required after start-up.
General three-phase motor drives
Crushers, conveyors and similar loads driven from AC 110–440 V mains, with 4 digital inputs, 2 relay outputs and Modbus RTU.
FAQ
How to confirm output voltage and current range?
AC 110–440 V (mains); 5.5–630 kW (matched motor power).
Which applications does it suit?
Three-phase AC motor drives — compressors, pumps, fans, crushers — with constant current, voltage ramp or pulse kick-start modes for heavy loads.
What information is needed for selection?
Site voltage, current, load type, control mode, installation conditions and process requirements.
Selection Inquiry
Share your industry, load conditions, voltage, current, power range and site environment — our engineers will help you confirm the right configuration.
