Siemens SIMOTICS-T 1FW68, Engineering Manual

Page: 118 / 180

Technical data and characteristics
6.1 Explanations
1FW68 radial segment motors
118
Configuration Manual, 04/2017, 6SN1197-0AE02-0BP1
Figure 6-1 Thermal time constant
p Pole pair number of the stator segment
M
COG
Cogging torque. This is the torque generated by the interaction between the lami-
nated core and permanent magnets at the air gap in stator segments that are in a
no-current condition.
The cogging torque can be calculated as follows:
Here, a
1
to a
n
are the amplitudes of the torque harmonics.
m
s
Mass of the stator segment without fixing screws, connectors, connecting cables
and coolant.
m
RS
Mass of the rotor segment (rotor segment without fixing screws and T-sliding
blocks).
m
R
Mass of the rotor (rotor segments without fixing screws and T-sliding blocks).
J
R
Moment of inertia of the rotor (rotor segments without fixing screws and T-sliding
blocks).
R
STR,20
Phase resistance of the winding at a winding temperature of 20 °C.
The value of the phase resistance is required for calculating the power loss,
among other things. R
20
can be converted for other phase resistances as follows:
R
STR
(T) = R
STR,20
∙ [1 + α (T – 20°C)]
with the temperature coefficients α = 0.00393 ∙ 1/K for copper.
The following applies for R
STR,130
: R
STR,130
= R
STR,20
∙ 1.4323.
L
STR
Phase inductance of the stator segment winding with installed rotor segment.