Overtemperature faults cluster in the first heat wave, which tells you most of them are installation debts, not component failures. The drive gives you separate clues — read them separately.
Which temperature tripped?
Heatsink overtemperature points outward: blocked filters, dead or tired fans (measure RPM or current, do not trust the blur), recirculating hot air in a packed panel, ambient beyond spec, or altitude derating nobody applied. Internal/electronics air points to the drive’s own microclimate: internal fan, or a sealed panel whose only cooling plan was hope. Motor temperature (thermal model or sensor) is a different investigation entirely: actual overload, missing motor ID poisoning the model, PTC wiring, or a motor whose own fan is gone at low speed duty — self-ventilated motors starve below ~50 % speed under torque.
The forensic details that solve repeat offenders
- Trend, don’t sample: log heatsink temperature across a shift; the shape (steady climb vs load-correlated peaks) separates airflow problems from duty problems.
- Panel design math: sum dissipation of everything in the enclosure against the cooling actually installed — retrofit panels accumulate devices without anyone re-running the thermal budget.
- Derating honesty: switching frequency raised for acoustic reasons costs real thermal headroom; check what commissioning “improved”.
FAQ
Can I just add a bigger external fan on the panel door? If filters and airflow paths are designed for it — random fans create random airflow. A proper air-path (in low, out high, filtered) beats raw CFM.
The drive derates itself before tripping — is that okay long-term? Automatic derating (reducing switching frequency/current) is graceful degradation, not a solution. Treat every derate event as a scheduled maintenance item.
Zone Otomasyon does thermal surveys on drive panels each spring — cheaper than August downtime. Book one.