SIEMENS
Selection and ordering
HT-direct motors 1FW4 air-cooled
3/9
Siemens D 86.2 · 2007
3
■
Additional information
Structure
Basic structure of the air-cooled HT-direct motor 1FW4
HT-direct motors have two cooling circuits that can be used to
achieve intensive and effective cooling:
•
The aluminium fan within the motor provides air circulation be-
tween DE and NDE. This cools, in particular, the stator winding
overhang, the magnetic rotor and the bearings.
•
The heat from the internal air is dissipated across the surface
of the motor housing. The external fan provides an even cool-
ing air-flow over the complete speed range of the HT-direct
motor.
Frame design
The housings are the same as the well-proven cast-iron hous-
ings of the 1LA4 series (H-compact motors). The condensation
water drainage holes are present and they are sealed during
transport. For certain applications (e.g. in shipbuilding and the
chemicals industry), external components made from aluminium
are not permitted.
In these cases, aluminium components (e.g. terminal boxes) are
replaced with other materials.
Forced ventilation
Forced ventilation is necessary to achieve even, intensive cool-
ing so that even at low speeds a high torque density can be
achieved.
Data of the external fan unit
G_D086_XX_00019
External fan unit
for motor type
1FW4 . . .
Fre-
quency
Voltage
Cur-
rent
Input
Air
flow
rate
Hz
V
A
kW
m
3
/s
. . . 401/403/405/407
50
230
d
11.1
1.6
1.7
400
*
6.4
60
460
*
6.2
2.8
2.02
. . . 451/453/455
50
400
d
8.2
2.3
2.10
690
*
4.7
60
460
d
7.9
4
2.5
. . . 503/505
50
400
d
11.4
3.6
2.75
690
*
6.6
60
460
d
10.9
6.3
3.3