CCC certified
Three starting modes: constant current, voltage ramp, pulse kick-start
On-line current monitoring with alarm
LED operating panel
KULUN / Soft Starter
MS21-H Soft Starter (High-performance)
KULUN MS21-H: bypass-type low-voltage AC motor soft starter with on-line monitoring, 5.5-630 kW for compressors, 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 | Real-time motor current monitoring with overcurrent protection | |
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-H is a bypass-type low-voltage AC motor soft starter with on-line current monitoring, 5.5–630 kW, with constant-current, voltage-ramp and pulse kick-start modes. Typical applications:
Heavy-load starts with current monitoring
Real-time motor current monitoring with overcurrent protection, for loads where start-up current needs to be supervised rather than assumed.
Pumps, fans and compressors
Adjustable 1–120 s start and stop ramps with soft stop or coast stop, up to 10 starts per hour; external bypass contactor required.
Drives integrated into a control system
4 digital inputs, 2 relay outputs and Modbus RTU for run, stop, jog, fault and bypass signals to a PLC or host system.
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.
