The SHZK ZKRZ-N Series is an online intelligent motor soft starter / soft-starter cabinet built to eliminate the damaging starting shock of large AC induction motors. Unlike a VFD, which controls motor speed continuously, a soft starter controls only starting current and torque — ramping the motor up smoothly, then dropping out to a bypass so the motor runs on full line power at full speed. It is the simplest, most cost-effective way to protect pumps, fans, conveyors, crushers and compressors from start-up spikes.
ZKRZ-N Series at a Glance
| Specification | ZKRZ-N Series |
|---|---|
| Drive type | Online intelligent motor soft starter / cabinet |
| Input voltage | AC 220 V / 380 V / 660 V optional |
| Motor power | 5.5 kW – 400 kW (standard); up to 630 kW on high-current models |
| Rated current | 11 A – 800 A (up to 1200 A on 660 V models) |
| Rated frequency | 50 / 60 Hz (auto-detect) |
| Suitable motor | Three-phase squirrel-cage AC induction motors |
| Starting modes | Voltage ramp, current limit, torque start |
| Stopping modes | Free stop, timed soft stop |
| Motor connection | Star or inner-delta (in-line soft starter) |
| Enclosure | Soft starter unit or integrated control cabinet |
| Protection | Phase loss, overcurrent, overload, over-temperature, phase sequence, current imbalance, short-circuit, plus more |
| Communication | RS485 Modbus RTU, 4-20 mA analog output, programmable relays |
| Display | Chinese + English interface on removable panel |
Why Use a Soft Starter Instead of Direct-On-Line (DOL) Starting?
Across-the-line (DOL) starting can pull 6–8× the motor’s full-load current and apply a violent torque spike the instant the contactor closes. That shocks the motor, stresses the driven machinery, and causes voltage dips on the whole supply network. The ZKRZ-N solves this with three selectable soft-start curves:
- Voltage ramp start — ramps voltage smoothly from a preset level to full voltage over a chosen time.
- Current limit start — caps starting current at a set multiple of rated current.
- Torque start — controlled torque build-up for heavy or high-inertia loads.
Soft stopping is equally important: the timed soft-stop mode lets a pump or conveyor decelerate gracefully instead of slamming to a stop, preventing water hammer and mechanical stress. A free-stop option is available when a rapid come-to-rest is acceptable.
Key Functions & Protection
Intelligent Protection
The ZKRZ-N continuously monitors the motor and drive and provides comprehensive, field-adjustable protection:
- Input & output phase loss
- Running overload (inverse-time) & underload
- Starting & running overcurrent
- Over-voltage & under-voltage
- Over-temperature / soft-starter overheating
- Phase sequence (rotation) failure
- Three-phase current imbalance
- Output short-circuit
Built-In Bypass & Control Options
After start-up, an internal bypass contactor closes so the motor runs directly on line power at full speed — the soft starter is then idle, so there is no continuous power loss or heat. Control is flexible:
- Front-panel soft key operation
- External terminal remote control (two-wire / three-wire systems)
- RS485 Modbus RTU for PLC / SCADA / host-plant integration
- 4-20 mA analog output and programmable relay outputs (7 selectable functions)
For water-supply systems, the ZKRZ-N offers dedicated pump-match modes (float switch, electric contact pressure gauge, supply/drain level relays) wired through the 24 V control loop.
Soft-Starter Unit or Control Cabinet?
Two physical configurations are available under the ZKRZ-N name:
- Soft-starter unit — the bare drive, designed to be wired into your existing panel or motor starter cabinet.
- Integrated soft-starter cabinet — a complete wall-mount or floor-standing enclosure with branch breaker, starter, bypass and terminal blocks, ready to connect.
The model code tells you which you are ordering, for example …-011A-Z for an 11 A soft-starter unit and …-S for a comprehensive cabinet.
Applications
- Water & irrigation pumps — soft start and soft stop, water-hammer reduction
- Fans & blowers — low starting torque, long fan and belt life
- Conveyors & belt systems — controlled torque transfer
- Air compressors — reduced inrush on screw and piston compressors
- Crushers, mills & heavy machinery — high-inertia starts without network sag
ZKRZ-N Model Naming
Model numbers are built as: [Product/Company] – [Series] – [Rated current] – [Device type]. For example, 011A means the drive is rated for 11 A; the final letter Z indicates a soft-starter unit and S a comprehensive control cabinet.
Technical Documentation
Download the full ZKRZ-N Series operation manual (PDF, ~1 MB) for complete wiring diagrams, terminal definitions, panel operation, parameter setup and the full fault-code table.