Siemens SINAMICS S 1PH7, Configuration Manual

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Mechanical properties of the motors
3.3 Bearing version
1PH7 induction motors (Machine tools)
Configuration Manual, (APH7W), 04/2009, 6SN1197-0AD72-0BP0
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3.3.2 Bearing lifetime
The bearing lifetime is limited by material fatigue (fatigue lifetime) or lubrication failure
(grease lifetime). The fatigue lifetime (statistical bearing lifetime L
10h
) is mainly dependent on
the mechanical load. The inter-dependency is shown in the radial force/axial force diagrams.
The values are determined according to DIN/ISO 281.
The grease lifetime is mainly dependent on the bearing size, speed, temperature as well as
the vibrational load.
The grease lifetime can be extended by especially favorable operating conditions (low or
average speed, low bearing temperatures, low radial force or vibration load).
A reduction of the grease lifetime can be expected for difficult operating conditions and when
motors are mounted vertically.
Lifetime lubrication (without re-lubricating)
For lifetime lubrication, the grease lifetime is harmonized with the bearing lifetime L
10h
.
Bearing change interval (t
LW
)
The recommended bearing change intervals are obtained from the inter-dependencies
mentioned above for a specific operating point such as:
● Coupling output or belt coupling
● Horizontal mounting position
● Cooling-medium temperature up to max. +40 °C
● Complying with the permissible radial and axial forces (refer to Chapter "Radial and axial
forces")
● Complying with the maximum permissible speeds (refer to Chapter "Technical data and
characteristics")
● The bearing change intervals are reduced for unfavorable operating conditions, for
example
– Average speed > as specified in the following table
– Vibration and shock load
– Frequent reversing operation
Note
When replacing the motor bearings, we also recommend that encoders with their own
bearings are also replaced.