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4.6.1.3. Dual speed three-phase motors
The diagram in fig. 29 shows the connection of a TWO-
SPEED MOTOR with two separate windings to the power
supply. TCF installs motors of this kind on its Units:
- 220/380 V for power ratings up to 5.5 kW
- 380/660 V for power ratings over 7.5 kW.
This type of electric motor permits delta-star connection
with starter.
The two-speed motors with a single DAHLANDER
commutable winding (fig. 30) (side connection) offer the
advantage of generating greater power than motors of the
same size but with separate windings.
4.6.1.4. Permitted start time
With regard to the temperature increase. the start-up
time of a motor may not exceed the value shown in table
1. In the case of repeated starts with unchanging rated
power the temperature of the motor must be the same as
it was before the first start. Therefore, in order for the
values in the table to be valid. it is assumed that the motor
is cold.
4.6.1.5. Recommended
connection
and
protection
accessories
Table 2 recommends, depending on the electric motor
installed in the Unit:
- the cross-section of the connecting cable, in copper or
aluminium
- the overload cut-out
- the fuse
lsp = starting current intensity
IN = rated current intensity
14
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