Warner Electric PTB-BL3 - Manual (Page 8)

8 Warner Electric • 800-825-9050 819-0368
Overhung Load Data
Note: Shaft extensions are not recommended.
When an overhung load (side load) is applied to
the shaft, verify that this load does not exceed
the maximum allowable. You will need to know
your operating speed and where your load is
applied to the shaft (See dimension 'A', Figure
8). For your speed, determine the speed coeffi-
cient from the coefficient table. Also, determine
the allowable overhung load from the chart
based on dimension 'A'. Multiply the load from
the chart times the speed coefficient to deter-
mine the allowable load for your application.
A (inches)
R (lbs)
Figure 8
Overhung Load
Allowable Overhung Load
Type A R A R A R
(In.) (Lbs.) (In.) (Lbs.) (In.) (Lbs.)
POC/POB-0.3 .40 30 .50 28 .90 22
POC/POB-0.6 .40 45 .50 42 1.0 29
POC/POB-1.2 .40 52 .70 43 1.4 31
POC/POB-2.5 .40 88 .90 67 1.7 48
PTB2.5-BL3
POC/POB-5 .40 204 1.1 136 2.2 93
PTB-5BL3
POC/POB-10 .40 313 1.3 235 2.6 159
PTB-10BL3
POC/POB-20 .40 379 1.4 265 2.8 198
PTB-20BL3
POC/POB-40 .40 581 1.8 432 3.6 324
POC/POB-80 .40 860 2.2 648 4.3 498
Note: This table is based on 1000 rpm and
6000 hours bearing life. Also, this table
assumes that no thrust load is applied.
For most applications, the overhung load is
caused by pulleys or sprockets. The smaller the
pitch diameter (P.D.) of the pulley or sprocket,
the higher the belt tension, and therefore the
higher the overhung load. To determine the mini-
mum pulley diameter for your application, use
the following equation:
Min. P.D.(in.) = 24 T K
C R
T - Torque (lb. ft.) This is the torque actually
being transmitted, not necessarily the maximum
torque capacity of the unit.
K - Safety factor for the tension in the type of
drive.
Use: 1.2 to 1.5 for sprockets
2 to 4 for belts
C - Speed coefficient from table.
R - Allowable Overhung Load from table.
Example: Determine the minimum sprocket
diameter that can be used on a POB-5.
Dimension A is 1.11 inches, required torque is
20 lb. ft. and the speed is 600 RPM.
Min. P.D.(in.) = 24 x 20 x 1.5
1.2 x 136
= 4.4 inch minimum P.D.
Speed Coefficient
Speed Speed Speed Speed
(rpm) coefficient (rpm) coefficient
50 2.74 1000 1.00
100 2.18 1200 0.95
200 1.72 1400 0.89
400 1.37 1600 0.86
600 1.20 1800 0.82
800 1.09 2000 0.80