Should high-temperature equipment (such as oven fans) choose C3 clearance?

High-temperature equipment (such as oven fans) typically requires C3 radial internal clearance for bearings, and here's the detailed reasoning:

Compensation for thermal expansion
High-temperature environments (often exceeding 100°C for devices like oven fans) cause significant thermal expansion of bearing components-including inner rings, outer rings, and rolling elements. C3 clearance, which is larger than the standard C0 (basic group) clearance, creates essential space to accommodate this expansion. Without this extra clearance, expanded parts would rub against each other, leading to increased friction, overheating, and even sudden bearing seizure.

Adaptation to operational stress
Equipment like oven fans not only operates at high temperatures but also endures continuous rotational stress and potential vibration. C3 clearance helps distribute this stress more evenly across the bearing, reducing the risk of localized wear (e.g., on raceways or rolling elements) and extending the bearing's service life. This is particularly critical for long-running, high-demand thermal equipment where downtime is costly.

Limitations to note
C3 clearance is not a "one-size-fits-all" solution. It is unsuitable for low-temperature, low-speed, or precision-sensitive equipment (e.g., small electronic cooling fans). For such cases, smaller clearances like C1 (extra small) or C2 (small) are more appropriate. The selection of C3 must always align with the equipment's specific temperature range, rotational speed, and load capacity (light, medium, or heavy).