Bearings with term CN

[magneticted]

Customer insisting on using anti friction bearing for AC motor with CN type ( Could be CM )I know nearly all motors have bearings with C3 fit. What do you think he may be reffering to

 

[raisinbran]

CN is a "normal fit" bearing, somewhere between a C2 and a C3 fit.
Raisinbran

 

[petronila]

Hello Magneticted,

You could find the two terms: CN and CM.

And both refers to the internal bearing´s clearance. this is the space providede the elements for a thermel expansion and grease film in order to avoid and prevent early bearings failures due to preloading.

The clearance are specified as C0,C2,C3,C4 and you could find some special manufacturers with C5.

CN is normal bearing clearance and is between C2 and C3 range,the tolerance of thermal effects is high whe the clearance is higher. The lower clearance are necessaries when you must be restric Vibration and noise.

CM Clearance is specified in some manufacturers designs where internal clearance help to reduce the noise.

Regards
Petronila