bearings for electric motors

[manzory]

hello,
is there a genaral rule when to use c3 bearings for electrical motors?
thanks.

 

[diskullman]

yes, always, some applications c4

Russell Giuliano

 

[caoimhin1]

Depends on the size in my experience. Medium to large motors tend to use C3. Smaller motors and ones used in home appliances and power tools tend to use CN.
I never understood why they use C3 on larger motors, I can't see the need personally. Are there large heat differentials?

 

[Fugeguy]

IMHO, motors use a variety of fits (including heavy presses) and temperature ranges.

Since the L10 penalty for a little too much clearance is a lot less than the penalty for things being too tight, C3 is used across the board, even though it is often not required.

 

[crjones]

The rotor also moves as the coils are energized and it seeks its magnetic center. So C3 allows it to move without adding preload to the bearing

 

[electricpete]

I tend to think Fugeguy is correct.

=====================================
Eng-tips forums: The best place on the web for engineering discussions.

 

[Fugeguy]

It all sounds good to me.

 

[Skogsgurra]

Good and down-to-earth reasoning. I also see mostly C3. Never asked why. Good to have an answer

Gunnar Englund

http://www.gke.org

--------------------------------------
100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...

 

[manzory]

thanks everyone!!!!
Yaniv.