Evidence to watch
The function is proved by changed behavior, not by a parameter value alone.
- Active and historical fault code
- Current, DC bus and temperature
- Command, reference, actual speed and load state
D-01 · vendor-neutral function
VFD Fault Codes and Diagnostic Method
A VFD fault code identifies which protection function operated; it does not by itself prove the failed component. Diagnose with the code, first-changing measurement, trip history and machine condition together.
Why it matters
The behavior behind the parameter.
The same overcurrent code can follow a short circuit, seized load, bad motor data or an acceleration ramp that is too aggressive. Evidence-led diagnosis prevents random parameter changes and repeat trips.
- Codes are vendor-specific; causes and electrical evidence are transferable.
- Remove the active cause and stop the run request before resetting.
- Preserve the trip history before cycling power.
Interactive proof
Test vfd fault codes and diagnostic method in three passes.
Keep the motor, load and starting condition constant. Change one function at a time, then use the electrical and mechanical evidence to explain the result.
- 01
Inject one fault in the diagnosis bay and record speed, current, DC bus and temperature.
- 02
Use the active code and measurements to separate supply, motor, drive and mechanical causes.
- 03
Remove the condition, clear the command and prove the reset permissive.
Common commissioning mistakes
These errors can make a healthy drive appear faulty or create a misleading test.
- Replacing the drive based only on the code.
- Resetting repeatedly while the cause remains active.
- Power-cycling before recording history and operating conditions.
Primary technical references
Transfer the concept; verify the exact drive.
This guide uses vendor-neutral terminology. For real equipment, use the manual for the installed model, option cards and firmware, plus the machine risk assessment and approved commissioning procedure.
Related VFD functions
F-41
VFD Current Limit and Stall Protection
Current limiting caps drive output current and therefore available motor torque. The drive may slow or extend acceleration instead of immediately tripping when the load demand reaches that limit.
Read and test F-22VFD Stop Modes: Ramp, Coast, Quick Stop and DC Brake
A VFD can ramp the frequency down, remove torque and coast, use a faster quick-stop ramp, or apply DC injection braking. Each produces a different current, torque, stopping time and DC-bus response.
Read and test S-01VFD Safe Torque Off (STO)
Safe torque off prevents the drive from generating motor torque when its safety channels are de-energized. It does not isolate mains power and does not necessarily stop a moving machine quickly.
Read and testFrom explanation to evidence