Control Techniques / Nidec high-performance drive service reference

Control Techniques Unidrive SP / Unidrive M service platform

A family-level diagnostic record for Unidrive SP and Unidrive M cases where the service question is usually a short trip label, a hoist/winder symptom, a feedback instability complaint or a failed control-supply condition.

Model-family evidence record10 min read

Scope of this technical record

Family-level Unidrive SP/M record for collecting the exact model, option module, feedback and machine-control evidence before interpreting trips.

Safety boundary

Model-family information does not replace the exact manual and risk assessment for the installed drive, motor, brake and feedback system.

Unidrive model identity route

1Model
2Option modules
3Feedback
4Brake / load
5Service route

Exact option and feedback identity decides the correct Unidrive repair route.

Unidrive model evidence image

Unidrive SP M model evidence route option modules feedback brake load and service route
The image shows why option modules and feedback identity matter before trip-code interpretation.

Identity evidence for Unidrive

Unidrive support should start with exact model, size, option module arrangement, feedback device, motor/brake data and parameter backup status. Without that context, OI.AC or Over Volts may be wrongly treated as a failed drive instead of a machine-loop issue.

Model evidence table

The model record is the place to capture configuration before removing hardware.

Unidrive identity evidence

EvidenceWhy it mattersAffected route
SP/M family and sizeDefines power-stage and braking/cooling expectationsAll routes
Option modulesFeedback, fieldbus and I/O behaviourPS.24V / feedback
Encoder type and wiringCan cause instability or overcurrent in closed loopOI.AC / feedback
Brake/load arrangementExplains start current and regenerationOI.AC / Over Volts
Parameter backupDetermines repair versus migration difficultyModernization boundary

Field record checklist

  • Exact model
  • Option modules
  • Feedback device
  • Brake/load arrangement
  • Parameter backup

Technical basis and reference documents

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

Control Techniques Unidrive manual mirrorVFDS.com

User-guide reference for setup and trip-log context.

Related technical records

OI.AC
AC Output Overcurrent Trip

Unidrive SP or Unidrive M trips on OI.AC during enable, acceleration, load change or unstable closed-loop operation.

Open →
Over Volts
DC Bus Overvoltage Trip

Unidrive trips on Over Volts during deceleration, hoist lowering, winder stop or high line condition.

Open →
PS.24V
24 V Control Supply Overload / Fault

Unidrive reports PS.24V, loses option/module supply, or drops control logic when external loads are connected.

Open →
Feedback / encoder instability
Encoder Feedback Noise or Instability

Closed-loop Unidrive application is unstable, trips under load, hunts, overspeeds or reports feedback-related symptoms.

Open →
Circuit
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.

Open →
Circuit
Unidrive DC Bus and Braking Path

Routes Over Volts evidence through line voltage, DC bus, load regeneration, deceleration ramp, brake resistor, brake chopper and feedback-induced instability.

Open →
Circuit
Unidrive Control Supply, Option Module and Feedback Path

Routes PS.24V, thermal feedback and encoder instability through external 24 V loads, option modules, feedback wiring, sensor supply, heatsink feedback and control-board evidence.

Open →
Workflow
Unidrive OI.AC Overcurrent Diagnostic Workflow

Unidrive SP/M reports OI.AC or trips during enable, acceleration, load change or closed-loop instability.

Open →
Workflow
Unidrive Over Volts Braking and Regeneration Workflow

Unidrive reports Over Volts during deceleration, lowering, stop, winder unwind or unstable closed-loop operation.

Open →
Workflow
Unidrive PS.24V / Thermal / Feedback Evidence Workflow

Unidrive reports PS.24V, thermal feedback symptoms, O.ht/O.ht1 or feedback instability with option modules and external control wiring.

Open →
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
Prepare request →