ATA QB S series medium voltage soft starter is designed for the start, operation, stop control and protection of medium voltage AC motors. It integrates computer control and power electronics technologies, adopting medium voltage high power thyristors as main circuit components. With an integrated circuit breaker design, it simplifies on site wiring and improves system safety and integration. By adjusting the thyristor conduction angle, it enables smooth voltage regulation and contactless motor start stop. It realizes ideal current starting, effectively lowering grid impact, equipment vibration, noise and mechanical stress, and prolonging the service life of motors and supporting devices. Boasting advanced technology, stable operation and comprehensive protection functions, this series reaches the international advanced level of similar products.
Medium-voltage thyristors serve as the main circuit components, equipped with voltage
sharing protection and over-voltage protection systems.
Advanced optical fiber or magnetic ring transmission technology isolates the trigger
detection of medium-voltage thyristors from the low-voltage control circuit.
The advanced digital signal processor (DSP) executes core control,
while the microcontroller manages data and communication—ensuring real-time, efficient
device control, intuitive display, high reliability and good stability.
Multi-level signal processing and isolation technology gives the system strong anti-interference capability.
Chinese/English display, membrane keys, simple operation and user-friendly interface.
Equipped with RS-485 or Profibus communication interfaces, enabling communication
with upper computers or central control centers.
Ramp Voltage Control, Current Limiting Control, Ramp Current Control, Soft Stop Control
Local Button Starting, Keyboard Key Starting, Upper Computer Remote Starting, Combination Starting
- Phase Loss & Undervoltage Protection
- Power Supply Overvoltage Protection
- Running Overcurrent Protection
- Thyristor Module Protection
- Instantaneous Overvoltage Protection
- Start Interval Time Protection
- Start Timeout Protection
- Interlock Control Protection
- Three-Phase Unbalance Protection
- Phase Sequence Protection
| Voltage range | 2kV-11kV |
|---|---|
| Current range | 120A-328A |
| Typical power range | 110kW-5000kW |
| Starting current limit | 150%-800% of rated current, adjustable |
| Starting modes | Voltage start / Ramp start / Current-limit start |
| Stop modes | Free stop / Soft stop |
| Protection functions | Phase Loss and Under-voltage Protection / Input Over-voltage Protection / Running Over-current Protection / Thyristor Module Protection / Instant Over-voltage Protection / Start Interval Protection / Start Timeout Protection / Instantaneous Over-current Protection / Interlock Protection |
| Communication interfaces | RS-485 and Profibus interfaces (optional) |
| Operating temperature | -20 to +50 degrees C |
| Altitude | Up to 1500m,(Derating is required for altitude >1500m) |
| Enclosure protection class | IP20 - IP54 (According to customer’s request) |
| Certifications for this specific model | CE / EAC |
| Equipment types this model is suitable for | Pumps / Fans / Compressors / Crushers / Mixers / Belt conveyors / Ball mills / Blowers |
|---|---|
| Industries and specific use case for each | - Steel and Metal — starting large rolling mill drive motors - Mining — compressor starts in underground environments - Petrochemical — pump starts on refinery sites |
Medium‑voltage three‑phase AC motors including squirrel‑cage induction motors and synchronous motors.
The core difference between QB‑S and QB‑H lies in structural design and power range: QB‑S adopts an integrated design with an extra built-in circuit breaker yet is limited to low power ratings, while QB‑H is the standard version capable of supporting high-power applications without the integrated breaker setup.
Soft start time 0~120s, soft stop time 0~60s, initial voltage 20~80%, kick start time 0~3s.
QB‑S adopts natural air cooling and is designed for indoor installation with a maximum protection grade of IP43; it can only be mounted under covered semi-outdoor eaves and is forbidden for open-air exposure.
Yes. It supports RS‑485 or Profibus interfaces, local pushbutton, keypad, host computer remote, and combined start modes.
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