Siemens SIMOTICS T-1FW68, Configuration Manual

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Mechanical properties
3.1 Cooling
1FW68 radial segment motors
54
Configuration Manual, 08/2021, A5E51132930B AA
Dimensioning the heat-exchanger unit
The power loss generated in the motor during continuous operation causes a thermal
flow to take place. The surrounding machine assembly dissipates a small percentage of
this thermal flow. The cooling system coolant dissipates the majority of this thermal
flow. The cooling system must dissipate 85% to 90% of the power loss that occurs.
Appropriately dimension the cooling system rating.
If you operate several stator segments simultaneously on one cooling system, then the
cooling system must be able to dissipate the sum of the individual power losses.
In continuous operation, only load the motor to the extent that the continuous rms torque
of the duty cycle M
eff
does not exceed the rated torque M
N
. In continuous operation, it is
not permissible for the operating point in the M-n diagram to be above the characteristic
for S1 duty. As a consequence, the maximum rms power loss P
V
only reaches the rated
power loss P
V,N
.
If you cannot determine the actual rms power loss P
V
then alternatively you can add the
rated power losses P
V,N
of all the stator segments to be used. The rated power losses
P
V,N
of the stator segments are listed in the data sheets. Dimension the heat-exchanger
unit based on the sum of the rated power losses determined P
V,N
.
If the sum of the rated power losses P
V,N
is greater than the actual rms power loss P
V
,
then this will lead to an overdimensioning of the cooling system.
The cooling system must be sufficiently powerful to ensure the required coolant pressure
even at the maximum volume flow rate.
3.1.2 Coolants
Provision of the coolant
The customer must provide the coolant. The motors are designed for use with an anti-
corrosion protection agent added to the water.
Note
Power derating when using oil as coolant
If you are using oil as coolant, then this can reduce the power loss dissipated by the
cooler. Appropriately reduce the motor power. Please contact your local Siemens office if
you have any questions.