Page 6 - Catalogue
P. 6
D. NOISE TESTING
The testing cooling fan runs in free air?ow and a noise meter is Set to 1 meter away from air
entrance and at 90degree to the fan in an echo-free room with background noise lower than
15db. The test result is depicted with sound pressure level frequency band . In DBAS .
E.BEARING TYPE
Bearing is an important part in the evaluation of the performance of the fan, and it is generally
used for sleeve bearing and ball bearing. The characteristics of the two kinds of bearings are
as follows：
NO. Item Sleeve Hydro Ball A?ect
1 Material Copper Copper Steel Expected Life
2 Support Surface Surface Point Friction heat
3 Tightness Open Open Close Expected Life
4 Oil volatility Easily Easily Not easily Expected Life
5 Mounting Vertical Vertical All angle Expected Life
6 Speed range Low speed Low speed All speed Expected Life
7 Temperature -10°C ~ +60°C -10°C ~ +60°C -20°C ~ +70°C Use environment
8 Expected life 20000HRS. 30000HRS. 50000HRS. Expected Life
9 Noise High High Low and stable Expected Life
10 Cost Cheap Cheap Expensive Price
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