OHF: high drive temperature
OHF covers the superheat of the drive. It is distinguished from the thermal protection of the engine: the framework context and the load are part of the diagnosis.
The case in 60 seconds
OHF covers the superheat of the drive. It is distinguished from the thermal protection of the engine: the framework context and the load are part of the diagnosis.
Count ambient temperature, now, load and service life before shutdown.
The code or symptom directs research, but does not show the fault component alone.
Diagnostic map
Follow the rows in order. Each phase must produce evidence before moving to the next.
| Phase | Controls | Evidence to obtain | Next decision |
|---|---|---|---|
| 01Recognize and collect |
| Event context and complete initial data. | If a data is missing, do not reset to attempts: complete the initial picture first. |
| 02Check and separate hypotheses |
| External causes, configuration, circuit and separate process. | If the data does not match, return to the correct schema and revision before changing parameters. |
| 03Interpret and demonstrate |
| Cause supported by repeatable data and authorized evidence. | If the cause is not proven, stop changes and involve manufacturer, OEM or machine manager. |
Reading and observation
Recognize and collect
- Count ambient temperature, now, load and service life before shutdown.
- Observe from outside or under safe conditions any ventilation obstructions; do not restart immediately.
Event context and complete initial data.
If the result does not matchIf a data is missing, do not reset to attempts: complete the initial picture first.
Qualified technician
Check and separate hypotheses
- Check ventilation status, cleaning and mounting conditions according to the installation manual of the size.
- Compare the actual load with the approved configuration and check that the cooling of the picture is available.
External causes, configuration, circuit and separate process.
If the result does not matchIf the data does not match, return to the correct schema and revision before changing parameters.
Specialist deepening
Interpret and demonstrate
- Use the thermal monitoring of the drive to correlate the event with current and environmental conditions.
- See the applicable declassification and assembly conditions; do not transfer thresholds between formats or revisions.
Cause supported by repeatable data and authorized evidence.
If the result does not matchIf the cause is not proven, stop changes and involve manufacturer, OEM or machine manager.
What to avoid
- Use repeated resets as a diagnostic test.
- Transfer codes, thresholds or parameters from one Drives family to another.
- Change a protection before connecting symptoms, measurement and phase of the cycle.
- Wait for the restoration of the conditions permitted by the manufacturer. If the problem reappears, stop the tests and verify the thermal cause.
When the problem is really solved
The closure requires documented thermal and load conditions, with stable operation in the planned cycle.
- The cause is supported by data and not only by the momentary absence of the alarm.
- The cycle that generated the problem has been repeated in authorized conditions.
- Final configuration, measurements and outcome are consistent with applicable machine, drive and documentation.
Applicable documents
Always check size, firmware, options and revision. These sources do not extend the case to other families.
- Primary source of the caseOpen the official source la
- Schneider Electric · Programming and DiagnosticManual · EN · NVE41295 · Official PDF
- Schneider Electric · InstallationManual · EN · NVE41289 · Official PDF