Configuration Manual AC Induction Motors 1PH4 - Siemens ...

Motor Description
1.9 Mounting
Natural frequency when mounted
The motor is a system which is capable of vibration at its natural frequency. For all
1PH motors, this resonant frequency lies above the specified maximum speed.
1-32
When the motor is mounted onto a machine tool, a new system capable of vibration
is created with modified natural frequencies. These can lie within the motor
speed range.
This can result in undesirable vibrations in the mechanical drive transmission.
Note
Motors must be carefully mounted on adequately stiff foundations or bedplates.
Additional elasticities of the foundation/bedplates can result in resonance effects of
the natural frequency at the operating speed and therefore result in inadmissibly
high vibration values.
The magnitude of the natural frequency when the motor is mounted depends on
various factors and can be influenced by the following points:
� Mechanical transmission elements (gearboxes, belts, couplings, pinions, etc.)
� Stiffness of the machine design to which the motor is mounted
� Stiffness of the motor in the area around the foot or customer flange
� Motor weight
� Machine weight and the weight of the mechanical system in the vicinity of the
motor
� Damping properties of the motor and the machine tool
� Mounting type, mounting position (IM B5; IM B3; IM B35; IM V1; etc.)
� Motor weight distribution, i.e. length, shaft height
�
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AC Induction Motors, 1PH4 (APH4) – 04.06 Edition