Application Scenarios
A plastics extrusion line running on a 1336 FORCE drive suddenly trips mid-production with an “Output Current Sensor Fault” code. The extruder barrel is full of molten polymer, and an unplanned shutdown means hours of purging and restart losses. The maintenance technician opens the drive enclosure, and the diagnostic code points directly to the 1336-CT-SP1A—the current transducer mounted on the power module side that samples the U, V, and W phase output currents . Without a properly functioning 1336-CT-SP1A, the drive’s control board loses its current feedback loop entirely. Vector control degrades to unreliable operation, overload protection becomes blind, and the drive either trips on sensor fault or runs with compromised torque accuracy . For plants still operating these legacy 1336 drives—now discontinued since 2015—the 1336-CT-SP1A is not a consumable; it is the component that determines whether the entire drive remains viable or becomes scrap .
Parameter
| Main Parameters | Value/Description |
|---|---|
| Product Model | 1336-CT-SP1A |
| Manufacturer | Allen-Bradley (Rockwell Automation) |
| Product Category | Current Transducer / Current Transformer |
| Compatible Drive Series | 1336 PLUS II, 1336 FORCE, 1336 IMPACT, 1336STG |
| Compatible Frame | 1336STG Frame D |
| Measurement Object | Three-phase output current (U, V, W) |
| Transformation Ratio | 1:2000 |
| Output Impedance | 25 Ω |
| Supply Voltage | 24 V DC |
| Primary Function | Current feedback, overload/overcurrent protection, current imbalance detection |
| Surge Protection | Internal Metal Oxide Varistor (MOV) |
| Mounting Location | Inside drive power module, near output terminals |
| Approximate Weight | 0.27 kg |
| Factory Status | Discontinued (March 2015) |
| Certifications | UL / CE / CSA (verify on nameplate) |
Technical Principles and Innovative Values
- Innovation Point 1: Dedicated Transformation Ratio Matched to 1336 Drive Architecture. The 1336-CT-SP1A employs a 1:2000 transformation ratio with 25 Ω output impedance, precisely calibrated to the signal conditioning circuitry of 1336 series control boards . This is not a generic industrial current transformer. Third-party substitutes with different ratios or impedance characteristics introduce amplitude or phase errors that the drive’s firmware was never designed to compensate. The result is often nuisance overcurrent trips or degraded low-speed torque performance—symptoms that mislead technicians into replacing the drive itself when only the 1336-CT-SP1A was mismatched .
- Innovation Point 2: Integrated MOV Surge Protection for Power Module Environment. Operating inside the drive’s power module, the is exposed to switching transients from the IGBT output stage. The built-in metal oxide varistor clamps voltage spikes that could otherwise damage the transducer’s sensing element or corrupt the feedback signal . This integrated protection extends the ‘s service life in an environment where generic sensors would degrade prematurely.
- Innovation Point 3: Critical Role in Vector Control Feedback Loop. The 1336 FORCE and IMPACT platforms rely on accurate output current feedback for field-oriented control. The provides the phase current signals that enable the drive to decompose stator current into flux-producing and torque-producing components. Without precise feedback from the , the drive cannot maintain torque accuracy at low speeds, and load compensation becomes erratic . This makes the not merely a protection component but a performance-enabling element of the drive architecture.
