1. Description

The 1336-CT-SP1A is a current transducer manufactured by Allen-Bradley (Rockwell Automation), designed specifically for the Bulletin 1336 series of adjustable frequency AC drives. It serves as a dedicated current-sensing component that provides real-time phase output current feedback to the drive‘s control board for vector control, overload protection, and torque regulation.

2. Application Scenarios

In a paper-converting facility, a 75 HP PowerFlex 1336 PLUS II drive running a center-winder struggled to maintain consistent web tension during acceleration and deceleration. The drive operated in open-loop V/Hz mode with calculated—not measured—motor current, resulting in tension variation of approximately ±8%. This fluctuation caused splice breaks that disrupted production.

The maintenance team installed the 1336-CT-SP1A current transducer option card and reconfigured the drive for closed-loop flux-vector operation. With real measured current feedback now available, the drive could modulate torque output based on actual load conditions rather than inferred values. Tension variation dropped to ±1.5%, splice-break incidents decreased by roughly 90%, and the line could maintain tension down to 0.3 Hz—a capability impossible with calculated current alone. As the plant‘s maintenance lead observed, adding the 1336-CT-SP1A effectively transformed a standard VFD into a precision closed-loop vector drive without changing the motor or power wiring .

3. Parameter