Mounting; Connecting The Ground Conductor - Siemens 1LA8 Series Operating Instructions Manual

Vertical and horizontal position
The following measures are required in order to
compensate any radial offset at the coupling and to
horizontally adjust the electric motor with respect to
the driven load:
Place shims under the motor feet to position it
vertically and to avoid stressing/distorting the
machines. The number of shims should be kept as low
as possible i.e. stack as few as possible.
To horizontally position the machine, push it laterally
on the foundation and ensure that the axial position is
maintained.
When positioning the motor, ensure that there is a
uniform axial gap around the coupling.

3.4 Mounting

Overview
In order to ensure smooth, vibration-free motor
operation, a stable foundation design is required, the
motor must be precisely aligned, and the components,
which are to be mounted on the shaft end, must be
correctly balanced.
Notice
Please refer IS: 12075: Mechanical vibration of rotating
electrical machines with shaft heights 56mm and
higher – Measurement, Evaluation and Limits of
Vibration severity.
Note
Motors that are attached by their mounting feet to the
wall (IMV5 or IMV6 construction) must be supported
by a wall strip.
Where belt drive is used it is of advantage to use
sliding rails to mount the motor so as to be able to set
the correct belt tension.
Caution
The bearings and shaft can be damaged if the
belt tension is too high. It is essential, therefore,
that you adhere to the permissible values.
Use machine fixing bolts with the necessary
strength class to IS: 1367-Part 3 (ISO 898-1)
(e.g. 10.9) for reliable mounting and safe
transmission of forces resulting from torque.
When selecting the bolts and the design of the
foundation you must take into account the
maximum forces occurring in the case of a fault
(e.g. short circuit or system transfers in phase
opposition).
10

3.5 Connecting the ground conductor

Connection to the motor
The motor earth conductor cross-section must be
compliant with the installation and erection
regulations, for example in accordance with IS: 3043
for cross-sections greater than 35 mm² of the phase
conductor, with a minimum of 50% of the cross-
section of the phase conductor.
There is a hexagon bolt with flat and spring washer on
the stator frame at the designated connecting point
for the earthing conductor. This is suitable to connect
multi-core conductors with cable lugs or straps with
appropriate conductor ends.
When making connections, ensure that
• The contact surface is clean and bright, and is
protected with a suitable anticorrosion agent, e.g.
Acid-free Vaseline.
• The flat and spring washers are located under the
bolt head.
• The maximum permissible clamping thickness for
the cable lug or strap of 10mm is not exceeded.
• The minimum required screw-in depth and the
tightening torque for the clamping bolts as given in
the following table are observed.
These differ depending on whether cable lugs or earth
terminals are used:
Tightening torques of bolts (cable lug)
Bolt Screw-in depth
M12 x 25 > 16 mm
M16 x 35 > 20 mm
Tightening torques of bolts (earth terminals)
Bolt Screw-in depth
M6 > 9 mm
M8 > 12 mm
M10 > 15 mm
M16 > 20 mm
Connection in the terminal box
In the terminal box, the labeled connection terminals
for the ground conductor should be used.
Tightening torque
38 Nm
92 Nm
Tightening torque
8 Nm
20 Nm
40 Nm
170 Nm