Allen-Bradley 809S-CT3 Continuous Current Transformer

The Allen-Bradley 809S-CT3 Continuous Current Transformer is a high-current current transformer with a 5 A secondary designed to feed Allen-Bradley 809S machine‑protection relays for motor protection in industrial automation. It accepts primary currents in the 42–500 A trip range and provides a 5 A secondary winding, with a continuous current rating of 750 A and an inrush capability of 3,500 A, enabling accurate sensing of motor load while tolerating brief current surges. This transformer is used in conjunction with 809S current relays (such as the 809S‑C1) to generate a trip signal when motor current exceeds programmed thresholds, helping prevent overheating and equipment damage in automated systems. Typical applications include protective monitoring of large motors and conveyors in manufacturing environments where robust, fast‑acting current sensing is required; the 809S-CT3 is part of Allen‑Bradley/MachineAlert protection solutions and is commonly paired with other 809S components for coordinated motor protection.