3.4.1 Earthing; Checking The Insulation Resistance - Siemens 1SE0 Operating And Maintenance Manual

In both the cases 6 terminals are brought
out & connection is made externally by
terminal links. Select the size of supply
cables as required for the particular current
rating. Connect the supply cables in
accordance with the connection diagram
shown inside the terminal box cover.
Danger
All work on the motor must only be
performed by qualified personnel, with
the motor in a stationary state. The sup-
ply should be secured so that it cannot
be switched back on again. Check that
no voltage is present before commenc-
ing work.
Connection and arrangement of the
terminal links must agree with the diagram
provided in the terminal box.
Refer fig. 3 and fig. 4 for various Terminal
box arrangements.
Please refer to the table below for
tightening torques for terminal bolts and
nuts (except for terminal strips).
Thread-ø Nm M4 M5 M6 M8 M10 M12
Tightening Min 0.08 0.18 0.28 0.56 0.92 1.43
Torque(Nm)
Max 0.12 0.25 0.41 0.82 1.33 2.04
Ensure that the direction of rotation of
the motor is as required. For induction
motors, the direction of rotation can be
reversed by interchanging two supply
phase connections in the terminal box. All
motors of type 1SE0 / 1LA2 are suitable for
bi-directional rotation.
Before closing the terminal box ensure
that:
– Interior of the terminal box is clean and
free of cable residue.
– All terminal screws and bolts are firmly
tightened.
– Minimum air-clearance (>10mm
upto 500V. >14mm upto 1000V) is
maintained.
– Unused cable entries are sealed off with
the plugging elements firmly screwed in.
– All sealing surfaces have adequate
contact.
In humid environments, motors which
are not in used should be connected to
Anti-Condensation Heaters to prevent
condensation of moisture. In case there
are no anti-condensation heater, a suitable
voltage (1ph) approximately 4 to 10 % of
the rated motor voltage should be applied
to stator terminals U1 and V1; 20 to 30
% of rated motor current is generally
sufficient to heat the motor enough to
prevent condensation. For safety reasons,
rotor should be locked to prevent rotation.
When the motors are provided with anti-
condensation heaters, ensure that the
supply to heaters is switched off before
switching on the motor.
Before starting and during operation,
make sure that all the relevant safety and
statutory regulations pertaining to the area
of operation is complied with.

3.4.1 Earthing

Connect the earthing conductor to the
terminal with the earth marking in the
Terminal box as well as on the Stator
housing.
Clean the area underneath the earthing
terminal and smear it with petroleum jelly
before making earthing connections.
3.5

Checking the insulation resistance

The insulation resistance of the windings
must be measured prior to initial startup
of the machine, and after long periods
of storage or standstill (approximately 6
months).
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