Single‑winding two‑speed starters are designed for motors that achieve low‑ and high‑speed operation using a single winding with multiple taps. Speed changes are accomplished by reconnecting portions of the winding in series or parallel. Control Innovations supplies single‑winding two‑speed starters built to handle these configuration changes safely and reliably.

A single‑winding two‑speed starter provides control for motors that use one winding with multiple taps to obtain two operating speeds. The starter reconfigures the winding connections using dedicated contactors to achieve low‑ and high‑speed operation.

Key Features

Control Innovations single‑winding two‑speed starters typically include:

• Three contactors to switch the winding between series and parallel configurations
• Electrical and mechanical interlocking to prevent incorrect or simultaneous energization
• Overload protection sized for both speed configurations
• Start/stop and speed‑selection operator controls

This provides a safe and reliable method for operating single‑winding (Dahlander) two‑speed motors.

Motor & Starter Characteristics

Single‑winding two‑speed motors:

• Use one winding with multiple taps
• Achieve low speed through series connection
• Achieve high speed through parallel connection
• Are lighter and less expensive than separate‑winding motors

However, the starters required for these motors are:

• More complex
• More expensive
• Designed to manage multiple winding configurations safely

Applications

Single‑winding two‑speed starters are commonly used in:

• Fans and blowers
• Pumps
• HVAC systems
• Industrial machinery requiring two fixed speeds

They provide a cost‑effective motor solution with a more sophisticated starter design