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Direct On Line (DOL) Starter

​Our Direct-On-Line (DOL) Starters provide reliable control and protection for medium voltage motors ranging from 1 kV up to 13.8 kV. As one of the simplest and most widely used motor starting methods, the DOL starter operates by directly connecting the motor to full line voltage through a contactor or vacuum circuit breaker, enabling straightforward and efficient motor starting.

All our DOL starter panels are type-tested in accordance with IEC standards, ensuring high levels of safety, performance, and compliance with international requirements.

Key Features:

  • Compact design with a small footprint

  • User-friendly and simple operation

  • Cost-effective solution with minimal maintenance requirements

  • No major spare parts required

  • Harmonic-free operation

  • Reliable and proven motor starting method

Starting Characteristics:

  • Motor starting current is typically 6–8 times the full load current

  • May result in mechanical stress and torque shock, especially in pumps and heavy-load applications

Variants of DOL Starters

1. DOL Starter with Vacuum Contactor

  • Suitable for ratings up to 13.8 kV, 400 A, 40 kA / 3s

  • Equipped with main disconnector switch and earthing switch

  • Electrical and mechanical interlocks ensure safe operation

  • Includes line fuses for protection along with a vacuum contactor

  • Features capacitive voltage indicators, indication lamps, and a motor protection relay

  • Provides complete safety for both motor and equipment

2. DOL Starter with Vacuum Circuit Breaker (VCB)

  • Suitable for ratings up to 13.8 kV, 1600 A, 40 kA / 3s

  • Available in fixed or withdrawable VCB configurations

  • Interlocked earthing switch and VCB for enhanced safety

  • Includes capacitive voltage indicators, indication lamps, and motor protection relay

  • Designed to ensure maximum protection of personnel and equipment

Optional Features:

  • Capacitor bank with 2% detuned reactor, along with fuses and contactor

  • Heater control circuit and oil pump supply for chiller applications

  • Flexible cable entry options (top or bottom) for incomer and outgoing cables based on site requirements

Enquiries

For further information, technical details, or customized solutions, please contact us to discuss your project requirements.

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