When we use open type bearing (Non-ZZ) and closed type (ZZ)

[jonos]

Dear Everybody,

Would you like to give reference/article about bearing open type (non-zz) and closed type (zz)?
When I use bearing non-zz and zz type? I have some information, if the motors below 15kW, is more better use bearing closed (zz) type and if the motor more >15 kW, is more better bearing open type.
Is it correct?
Thank you for your explanation
Best regard,
jonos

 

[GusD]

Hi jonos

Some small motors are not equipped with inner bearing covers.In this case you have to have something to stop grease from working itself out of the bearing.If motors have inner bearing caps and grease fittings, than you should use the non ZZ bearings .Normally, if a motor does not have an inner bearing cap,you leave the shield (z) on that side and remove the other on the other side,so you will be able to regrease bearing.

GusD

 

[jbartos]

Suggestion: Visit

http://www.ntnamerica.com/Engineering/PDFs/2200/mini_xs.pdf

http://www.precision-bearing.com/technical.html#shield

http://www.precision-bearing.com/technical.html

http://www.ca.nsk.com/page.asp?ID=443

(for specialty designed seals/shields)
etc. for more info