Thermal management as part of VSD servicing — complete cabinet airflow design and inspection guide

A fully repaired VSD installed back into a cabinet with inadequate airflow will fail again within months, and the root cause will be misattributed to electronics rather than thermal environment. This article makes the case for treating thermal auditing as a mandatory element of every drive service. Section one explains airflow pressure drop budget calculation accounting for fan count, filter dimensions, equipment layout, and ambient factory temperature. Section two covers actual CFM measurement with a digital anemometer against the original design specification; a measured drop greater than 15% typically indicates a clogged filter or damaged fan blade. Section three teaches IR thermography use for identifying hotspots on bus bar terminals, IGBT modules, and braking resistors — including guidance on safe measurement distance and emissivity settings for metallic surfaces. Section four addresses cable routing: the effect of cable paths on airflow patterns, required clearance between power cables and air exhaust channels, and the thermal risks of tangled cable bundles. The article concludes with our standard thermal audit report form for documenting cabinet thermal status before and after service.