Heavy-Duty Reduced Voltage Starting Solution for Large Three-Phase Motors

Product Overview

The 28kVA–1000kVA Autotransformer Motor Starter is a reliable reduced-voltage starting solution designed for medium and large three-phase induction motors. Utilizing a three-phase autotransformer during startup significantly reduces inrush current, minimizes voltage drop across the power system, and protects both motors and electrical infrastructure from excessive starting stress.

Housed in a rugged NEMA 3R metal enclosure, the starter is suitable for indoor and semi-outdoor installations where protection against rain, dust, and external contaminants is required.

Widely used in factories, mining operations, water treatment facilities, construction projects, and heavy industrial applications, it provides smooth motor acceleration and long-term operational reliability.

Protection Functions

Key Features & Advantages

Reduced Starting Current

The autotransformer starter lowers the motor starting voltage through selectable transformer taps, reducing starting current to approximately 30%–60% of direct-on-line (DOL) starting current.

Benefits include:

• Reduced voltage drop on the power network

• Lower mechanical stress on equipment

• Extended motor service life

• Improved power system stability

NEMA 3R Metal Enclosure

The durable steel enclosure protects against:

• Rain and water splash

• Dust and airborne contaminants

• Falling debris and foreign objects

Suitable for:

• Industrial workshops

• Pump stations

• Outdoor equipment shelters

• Semi-exposed installation environments

Comprehensive Motor Protection

Integrated protection functions help safeguard motors and electrical systems under demanding industrial conditions.

Protection against:

• Overcurrent

• Short circuit

• Phase loss

• Overload

• Overvoltage

• Overheating

This significantly reduces equipment downtime and maintenance costs.

Smooth Motor Acceleration

Multi-tap autotransformer technology provides a gradual voltage increase during startup, ensuring:

• Smooth acceleration

• Reduced mechanical shock

• Lower stress on couplings, belts, gears, and bearings

• Improved operational reliability

Easy Installation & Maintenance

The cabinet-style design offers:

• Clear wiring layout

• Convenient terminal access

• Simplified commissioning

• Easy routine inspection and maintenance

Ideal for both new installations and retrofit projects.

Technical Specifications

Typical Applications

✅ Water pumps and pumping stations
✅ Industrial fans and blowers
✅ Air compressors
✅ Conveyor systems and belt drives
✅ Ball mills and grinding equipment
✅ Crushers and mining machinery
✅ Polishing and processing equipment
✅ Water treatment facilities
✅ Metallurgical and manufacturing plants

Why Choose Our Autotransformer Starters?

✔ Reduced motor starting current and power grid impact
✔ NEMA 3R enclosure for industrial environments
✔ Complete motor protection package
✔ Smooth and reliable motor acceleration
✔ Heavy-duty construction for continuous industrial use
✔ Available from 28kVA to 1000kVA capacities
✔ Custom voltage and motor power configurations available

Contact Us for Custom Motor Starting Solutions

Looking for a reliable reduced-voltage starter for large industrial motors?

We provide:

• OEM & customized autotransformer starters

• Motor starting solutions from 22kW to 800kW

• Engineering support and technical consultation

• Fast production and worldwide shipping

📩 Send us your motor voltage, power rating, and application details today for a fast quotation and professional recommendation.