IndustrialDriveDataDrive Board & Diagnostic Database
Inverter output / closed-loop control

Unidrive Output Current, Vector Control and Feedback Path

Routes OI.AC and unstable closed-loop behaviour through motor cable, output bridge, current feedback, brake release, encoder feedback, shielding and tuning context.

Circuit-path evidence record9 min read

Scope of this technical record

Maps Unidrive output current, vector-control and feedback evidence from output bridge to motor cable, brake, encoder and control loop.

Safety boundary

Secure machine motion before testing output or feedback paths.

Unidrive output/vector path

1Output bridge
→
2Current feedback
→
3Motor / brake
→
4Encoder
→
5Vector loop

OI.AC requires both output hardware and feedback-loop evidence.

Unidrive output/vector path image

Unidrive output current vector feedback path output bridge motor brake encoder control loop
The image places OI.AC inside both output and feedback loops.

Output path plus feedback loop

Unidrive OI.AC cannot be mapped only as U/V/W output hardware. In closed-loop machines, current demand is shaped by feedback and brake/load behaviour. The path includes output bridge, current feedback, motor cable, brake, motor, encoder, feedback option and vector-control loop.

Path table

Use each node to decide whether the next action is field work or drive repair.

Unidrive output/vector path

NodeEvidenceFault route
Output bridge/current feedbackTrip persists after field proofPower-stage route
Motor cableInsulation or movement evidenceExternal path
Brake/loadHeld brake or jamMachine path
EncoderDirection/noise/supplyFeedback path
Vector loopHunting or unstable currentParameter/tuning route

Field record checklist

  • Output bridge
  • Motor cable
  • Brake/load
  • Encoder
  • Control loop

Technical basis and reference documents

This is an independent editorial technical reference. Original manufacturer documentation remains controlling for installation, repair and commissioning decisions.

Unidrive SP trip-code referenceDrives and Automation

Public context for OI.AC and related trips.

Evidence intake

Turn this record into a qualified service request

A repair decision is much more reliable when the request includes the exact identity of the drive, the first fault evidence and the machine condition when the symptom appeared.

  • Complete drive type code / MLFB or nameplate model
  • Fault code, fault value and first event before reset
  • When the event appears: power-up, enable, ramp, run, decel or stop
  • Motor/cable connected or isolated during the symptom
  • Visible board, option-card, module and connector identifiers
  • Previous repair history, replacement parts and repeat-failure pattern
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