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QZB Series 3 phase reduced voltage Autotransformer Motor Starter
Product Overview
The QZB Series Autotransformer Motor Starter is a three-phase industrial reduced-voltage starting transformer designed for short-time motor starting applications. Widely used in global industrial projects, it is primarily used for the soft starting of three-phase squirrel-cage induction motors.
By reducing motor starting current, the QZB starter effectively minimizes voltage drops in the power grid while protecting motors, electrical equipment, and upstream distribution systems from the impact of excessive inrush current.
Designed and manufactured according to international industrial standards, the QZB series offers stable performance, high reliability, and efficient motor starting for heavy-duty industrial equipment such as:
Fans
Water pumps
Air compressors
Crushers
Large conveyor systems
It is an ideal motor starting solution for industrial plants, mining projects, water treatment facilities, and power systems worldwide.
Working Principle
The QZB starter operates using autotransformer reduced-voltage starting technology.
During motor startup, the transformer lowers the input voltage through built-in voltage taps, significantly reducing the motor starting current. Once the motor reaches a stable operating speed, the system automatically switches to full-voltage operation.
The transformer is designed only for short-duration starting duty and does not carry a continuous load during normal operation, ensuring:
Energy-efficient operation
Extended service life
Reduced thermal stress
Standard Technical Specifications
| Item | Specification |
|---|---|
| Operating System | Three-Phase AC 50/60Hz |
| Rated Input Voltage | 380V / 415V / 660V / 690V (Customizable) |
| Starting Voltage Taps | 65% / 80% Standard Dual Taps |
| Starting Current Reduction | Limits current to 40%–65% of rated current |
| Applicable Motor Power | 14kW – 500kW |
| Insulation Class | Class H (180°C) |
| Cooling Method | AN Dry-Type Self-Cooling |
| Protection Rating | IP21 Standard (IP54 Optional) |
| Enclosure Finish | Industrial Anti-Corrosion Coating |
| Standard Color | RAL7035 Light Gray |
| Duty Type | Short-Time Intermittent Starting Duty |
Key Features & Advantages
High-Quality Silicon Steel Core
Manufactured using high magnetic permeability cold-rolled silicon steel laminations for:
Low no-load loss
Reduced operating noise
Stable electrical performance
Improved energy efficiency
Full Copper Windings with Vacuum Impregnation
The transformer uses high-quality copper windings combined with vacuum varnish impregnation technology to provide:
Excellent insulation performance
Moisture resistance
Corrosion resistance
High-temperature durability
Ensures reliable operation in demanding industrial environments.
Dual-Tap Reduced Voltage Starting
Equipped with standard 65% and 80% voltage taps to match different motor load conditions.
Benefits include:
Smooth motor acceleration
Reduced mechanical shock
Lower electrical stress on the power system
Improved equipment protection
Compact & Maintenance-Free Design
Features a compact modular structure for:
Easy installation
Simplified wiring
Minimal maintenance requirements
Suitable for industrial control systems and integrated motor starter panels.
Protects Power Systems & Equipment
Effectively reduces the impact of heavy motor startup on:
Distribution transformers
Power grids
Mechanical transmission systems
Industrial electrical infrastructure
Widely used in:
Factories
Water treatment plants
Mining operations
Power stations
Industrial processing facilities
Suitable Operating Environment
Designed for standard industrial environments:
Ambient temperature: -5°C to +40°C
Altitude: ≤2000m
Indoor installation
Non-corrosive atmosphere
No severe vibration conditions
Suitable for global industrial power systems.
Typical Applications
✅ Industrial motor starting systems
✅ Water pump systems
✅ Air compressor equipment
✅ Mining machinery
✅ Conveyor systems
✅ Crushers and heavy-duty machinery
✅ Industrial production lines
✅ Water treatment plants and utilities
Product Advantages Summary
✅ Reduced motor starting current and voltage drop
✅ Protects motors and power distribution systems
✅ Full copper winding with high insulation performance
✅ Dual-tap voltage starting for flexible applications
✅ Compact structure with easy installation
✅ Reliable operation for heavy-duty industrial equipment
✅ International industrial standard design
Contact Us for Motor Starter Transformer Solutions
Looking for a reliable reduced-voltage motor starter for your industrial project?
We provide:
OEM & customized autotransformer starters
Flexible voltage and motor capacity solutions
Engineering support for industrial applications
Fast production and worldwide delivery
📩 Contact us today with your motor specifications and project requirements for a fast quotation and professional recommendation.
