11239449 Installation, operation and maintenance manual – Squirrel cage motor – W Line - Horizontal and vertical l 29
4.8
MECHANICAL ASPECTS
4.8.1
Foundations
The foundation or structure where the motor will be
installed must be sufficiently rigid, flat, free of external
vibration and capable to withstand the mechanical
loads to which it will be submitted;
If the dimensioning of the foundation is not carefully
executed, this may cause vibration in the foundation,
on the motor and the driven machine;
The foundation structural design must be done based
on the dimensional drawing, on the information about
foundation mechanical loads, and on the motor
anchoring method.
ATTENTION
Place shims of different thicknesses between
the motor supporting surfaces and the
foundation in order to allow a precise
alignment.
NOTE
The user is responsible for dimensioning and
building the foundation where the motor will
be installed.
4.8.2
Foundation loads
Based on Figure 4.7, foundation loads can be calculated
by the equations:
Where: F1 and F2 - Reaction of the feet on the base (N)
g - Acceleration of gravity (9.81m/s²)
m - Motor mass (kg)
Cmax - Maximum torque (Nm)
A - Obtained from the motor dimensional drawing
(m)
Figure 4.7: Foundation loads
4.8.3
Base types
4.8.3.1
Concrete base
Concrete bases are the most widely used for the
installation of these motors.
The type and size of the foundation, bolts and anchoring
plates depend on the motor size and type.
Example of preparation:
Remove all the dirt from the foundation to ensure a
proper binding between the foundation blocks and the
mortar.
Fasten the foundation blocks to the motor feet using
bolts.
Use shims of different thicknesses (total thickness of
approximately 2 mm) between the motor feet and the
foundation surfaces in order to obtain a precise vertical
alignment.
In order to ensure the centralization of the bolts
regarding the foot holes, use a metallic or a cardboard
(prespan) sheet as bushing, making possible a precise
horizontal alignment later.
Place shims or leveling bolts under the foundation
blocks to ensure proper leveling and perfect alignment
of the motor with the driven machine. After the mortar
is applied, the alignment must be precisely controlled.
Occasional small corrections may be done with
washers or metal sheets or by readjusting the
clearance of the fastening bolts.
Tighten all the fastening bolts firmly. Make sure the
motor feet surfaces are supported evenly without
distorting the motor frame.
For precise fixation, introduce the tapered pins after
finishing the test.
4.8.3.2
Sliding base
In case of pulley drive, the motor must always be
mounted on a sliding base (rails), and the lower part of
the belt must be tightened.
The rail closer to the driving pulley must be mounted so
that the positioning bolt is placed between the motor and
the driven machine. The other rail must be mounted with
the bolt in the opposite position, as shown in Figure 4.8.
The motor is bolted on rails and positioned on the
foundation.
The driving pulley is then aligned so that its center and
the center of the driven pulley are in the same plane, and
the motor and machine shafts are perfectly parallel.
The belt must not be stretched too much. After the
alignment, the rails are fixed.
Figure 4.8: Sliding base
)
(
max)
4
(
.
.
.
5
.
0
1
A
C
g
m
F
)
(
max)
4
(
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5
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0
2
A
C
g
m
F
