15
Installation and maintenance - Three-phase induction motors
4850 en - 2018.11 / f
ASSEMBLY
2.5.4 - Terminal block wiring diagram
All motors are supplied with a wiring diagram in the terminal
box*.
The connector links required for coupling can be found inside
the terminal box.
Single-speed motors are fitted with a block of 6 terminals
complying with standard NFC 51 120, with the terminal
markings complying with IEC 34 - 8 (or NFC 51 118).
Particular attention must be paid to the
information on the nameplate in order to choose
the correct type of connection for the supply voltage.
2.5.5 - Direction of rotation
When the motor is powered by U1, V1, W1 or 1U, 1V, 1W from
a direct mains supply L1, L2, L3, it turns clockwise when seen
from the drive end.
If 2 phases of the power supply are changed over, the motor
will run in an anti-clockwise direction (make sure the motor has
been designed to run in both directions of rotation).
Warning: motor with backstop: starting in the wrong direction
destroys the backstop (see arrow on motor housing).
If the motor is fitted with accessories (thermal protection or
space heater), these should be connected on screw dominos
or terminal blocks with labelled wires (see section 2.4).
Temperature probe
2.5.6 - Earth terminal
This is situated inside the terminal box; in some cases, the
earth terminal may be situated on one of the feet or on one of
the cooling fins (round motors).
It is indicated by the symbol:
It is compulsory to earth the motor. Earthing
must be performed in accordance with current
regulations (protection of workers).
* If required, this diagram should be obtained from the supplier,
specifying the motor type and number (shown on the motor
nameplate).
2.5.7 - Connecting the power supply cables to
the terminal block
The cables must be fitted with connectors suitable for the cable
cross-section and the terminal diameter.
They must be crimped in accordance with the connector
supplier’s instructions.
Connection must be carried out with connector resting on
connector (see the diagrams below):
Tightening torque (N.m) on the terminal block nuts
Terminal M4
M5
M6
M8
M10 M12 M14 M16
Steel
1
2.5
4
10
20
35
50
65
Brass
1
2
3
6
12
20
-
50
If using cables without connectors, attach some calipers.
If any nuts on the brass terminal block are lost, they must be
replaced by brass nuts, not steel ones.
When closing the box, ensure that the seal is correctly
positioned.
As a general rule, check that no nut, washer or
other foreign body has fallen into or come into
contact with the winding.