Technical data

5
48
Manual – Gear Units and Gearmotors
Service factor
Project Planning for Gear Units
5.4 Service factor
Determining the
service factor
The effect of the driven machine on the gear unit is taken into account to a sufficient level
of accuracy using the service factor f
B
. The service factor is determined according to the
daily operating time and the starting frequency Z. Three load classifications are taken
into account depending on the mass acceleration factor. You can read off the service
factor applicable to your application in Figure 8 . The service factor determined from this
diagram must be smaller than or equal to the service factor according to the selection
tables.
Load classification Three load classifications are distinguished:
(I) Uniform, permitted mass acceleration factor ≤ 0.2
(II) Non-uniform, permitted mass acceleration factor ≤ 3
(III) Extremely non-uniform, permitted mass acceleration factor ≤ 10
00656BXX
Figure 8: Service factor f
B
* Daily operating time in hours/day
** Starting frequency Z: The cycles include all starting and braking procedures as well as changes from
low to high speed and vice versa.
Tf T
a
•
b a max
f
B
0 200 400 600 800 1200 14001000
24* 16* 8*
0.8
0.9
1.0
1.1
1.2
1.3
1.4
1.5
1.6
1.0
1.1
1.2
1.3
1.4
1.5
1.6
1.7
1.2
1.3
1.4
1.5
1.6
1.7
1.8
Z [1/h] **
(III)
(II)
(I)