Brochure
Mtd. Ball
Bearings
G-225
®
Mounted Ball Bearing Engineering Section
Mounted Ball Bearing Selection -
New Applications:
Using variations of the life formulas and application
information, it is possible to select bearings based
on desired life, load applied, and shaft speed. This
method can only be applied where axial load is less
than or equal to 1/2 the radial load.
1. Determine required application hours (Lna).
2. Calculate L
10
using adjustment factors:
L
10
=
3. Calculate Basic Dynamic Radial Rating (Creq).
Creq = P x
P = Constant Equivalent Radial Load (lbs)
N = Speed (RPM)
4. Use Table No. 4 and 5 on page G-227 to G-229, nd
a basic Dynamic Radial Rating Value greater than or
equal to Creq calculated in step # 3.
5. Select any bearing from the row in step # 4 or larger.
If Creq is greater than the largest Basic Dynamic Radial
Rating Value of Table No. 4 or 5, go to the Mounted
Roller Bearing Section H and I.
6. If Ball bearing is selected, proceed with housing,
seal, and lock selection.
Typical operating temperature range for standard
bearings is -20° to 200° F for Browning and -20°F to
220°F for Sealmaster Gold. For operating tempera-
tures outside this range, contact Application Engineer-
ing. For Maximum speed information, see tables on
pages G-235 and G-243
Application Examples:
Example #1 - Pure Radial Load
Question #1:
What is the adjusted bearing life (L
na
hours) for an NP-
39 Sealmaster Ball Bearing with no shock conditions
and the following application criteria?
Design Load (P) = 1300 lbs.
Speed (n) = 1000 RPM
Shaft Size = 2 7/16 in.
Operating Temp. = 125°F
Solution:
1. Begin with the L
10
life formula:
L
10
= (C/P)
3
x
Look up the insert of an NP-39 on page G-31. From
Table No. 4 on page G-228, the Basic Dynamic Radial
Rating is 11,789 lbs.
L
10
= x = 12,430 hours
2. Apply the life adjustment factors:
L
na
hours = L
10
x a
1
x a
2
x a
3
L
na
hours = 12,430 x 1 x 1 x 0.456
L
na
hours = 5,700 hours
16667
1000
L
a
a
1
x a
2
x a
3
L
10
x N
16,667
(
1/3
(
Load Ratings and Life Continued
16667
n
11789
1300
(
3
(