30 l
Installation, operation and maintenance manual – Squirrel cage motor – W Line - Horizontal and vertical 11239449
4.8.3.3
Metal base
The motor must rest evenly on the metal base in order to
prevent deformations of the frame. Occasional errors in
the height of the surface that supports the motor feet can
be corrected with shims (a maximum height of 2 mm is
recommended).
Do not remove the machines from the common base to
align them. The base must be leveled on the foundation
by using spirit levels or other leveling devices.
When a metal base is used to align the height of the
motor shaft end with the machine shaft end, it must be
leveled on the concrete base.
After the base has been leveled, the anchor bolts
tightened and the couplings checked, then the metal
base and the anchor bolts are cemented.
4.8.3.4
Anchor bolts
Anchor bolts are devices to fasten the motors directly on
the foundation when the motors are applied with elastic
coupling. This coupling type is characterized by the
absence of loads on the bearings.
The anchor bolts must neither be painted, nor present
rust, since that impairs the adhesion to the concrete,
loosening them.
Figure 4.9: Anchor bolts
4.8.4
Natural frequency of the base
In order to ensure a safe operation, the motor must be
precisely aligned with the coupled equipment and both
must be properly balanced.
As a requirement, the motor installation base must be flat
and meet the requirements of DIN 4024-1 standard.
In order to verify if the criteria of the standard are being
met, the following potential vibration excitation
frequencies generated by the motor and coupled
machine must be checked:
The motor rotation frequency;
The double of the rotation frequency;
The double of the motor electric frequency.
According to DIN 4024-1 standard, the natural
frequencies of the base or foundation must be away from
these potential excitation frequencies, as specified next:
The first natural frequency of the base or foundation
(first order natural frequency of the base) must be out
of the range from 0.8 to 1.25 times any of the potential
excitation frequencies above;
The other natural frequencies of the base or foundation
must be out of the range from 0.9 to 1.1 times any of
the potential excitation frequencies above.
4.8.5
Leveling
The motor must rest on a surface with flatness of up to
0.08 mm/m.
Verify whether the motor is perfectly leveled, both in the
vertical and horizontal planes. Make the proper
adjustments by placing shims under the motor. The
motor leveling must be checked with proper equipment.
NOTE
At least 75% of the motor foot support
surfaces must rest on the motor base.
4.8.6
Alignment
The motor must be correctly aligned with the driven
machine.
ATTENTION
Incorrect alignment can damage the
bearings, generate excessive vibration and
even break the shaft.
The alignment must be done according to the coupling
manufacturer recommendations.
The motor and driven machine shafts must be aligned in
the axial and radial directions, as shown in Figure 4.10
and Figure 4.11.
Figure 4.10: Parallel alignment
Figure 4.10 shows the parallel misalignment of the two
shaft ends and the practical way to measure it by using
suitable dial gauges.
The measurement is performed in four points 90° away
from each other with the two half-couplings rotating
together in order to eliminate effects of support surface
irregularities on the dial gauge tip. Choosing the upper
vertical point as 0°, half of the difference between the dial
gauge measurements at the 0° and 180° points
represents the vertical coaxial error. In case of deviation,
it must be corrected by adding or removing leveling
shims. Half of the difference between the dial gauge
measurements at the 90º and 270º points represents the
horizontal coaxial error.
These measurements indicate when it is necessary to lift
or lower the motor, or move it to the right or to the left on
the drive end in order to eliminate the coaxial error.
Horizontal Mounting Vertical Mounting
Radial measurement
Parallel misalignment
