Baldor PC SEries Bedienerhandbuch PDF herunterladen (Seite 13)

MN1240 Installation 2-5

Life Determination

How Life is Determined

A life estimate is a calculated, statistical expectancy and is defined as the

length of time, or the number of revolutions, until fatigue develops. This life

depends on many different factors such as loading, speed, lubrication,

operating temperature, contamination, plus other environmental factors. It’s

impossible to predict precisely.

Statistical calculation estimates are based upon L

life. This is the life that 90

percent of a group, of apparently identical parts, will reach or exceed. Typical

bearing radial load capacity curves presented in the literature are based upon

bearing L

life of 20,000 hours.

Using the Curves

First determine your load (or force), location (or distance) from the bearing the

load will be applied, and speed (or RPM). Typical bearing radial load capacity

curves presented in the literature are based upon bearing L

life of 20,000

hours for a BSM80 Motor, (Figure 2-3). Second, plot these points on the

curve. For example, a force of 80 lbs (352 N), applied 1 inch (25mm) from the

bearing, with a motor speed of 2,000 RPM, would relate to a bearing L

life

estimate of 20,000 hours.

Figure 2-3

X"

(Radial Force)

Operating 24 hours / day, which is 8500 hours, this would provide a L

life

estimate of: (20,000 hours) (8500 hours/yr)=2.35yrs.

If Plotted Point Does Not Match your RPM

Many times the point plotted (force and distance), is not specifically on your

applications speed curve, so an estimate for life is calculated as follows:

16667

Where: L

= 20,000 hours

S = RPM

C = capacity of system

F = Force or Load (lb)

1 2 ... 8 9 10 11 12 13 14 15 16 17 18 ... 23 24

Keine Kommentare

Baldor PC SEries Bedienerhandbuch Seite 13