Siemens SIMOTICS L-1FN3 Configuration Manual page 170

Technical data and characteristics
6.1 Explanations
Physical constants
k Force constant of the motor with a rated air gap and a secondary section temperature of 20 °C.
F,20
Comment: The force constant refers to the linear (lower) section of the motor force-current
characteristic.
k Voltage constant for calculating the mutually induced voltage between the phase and the star point
E
with a rated air gap.
k Motor constant at a winding temperature of 20 °C.
M,20
Comment: The motor constant k
k (T) = k
M
R Line resistance of the winding at a winding temperature of 20 °C.
STR,20
Comment: The line resistance R
R
STR
L Phase inductance of the winding with a rated air gap.
STR
F Attraction force between the primary section and the secondary section with a rated air gap.
A
t Thermal time constant of the motor winding
TH
Comment: The thermal time constant is obtained from the temperature characteristic in the motor
winding for a sudden load with constant current at time t = 0,, see the following figure. After time t
has elapsed, the motor winding reaches approx. 63% of its final temperature T
temperature protection does not respond beforehand.
Figure 6-1
τ Pole width of the motor, corresponds to the distance between the respective centers of the north and
M
south poles of neighboring magnets on a secondary section.
m Mass of the primary section without precision cooler, mounting screws, plugs, connection cables and
P
coolant.
m Mass of the primary section with precision cooler, but without mounting screws, plugs, connection
P,P
cables and coolant.
m Mass of a secondary section without mounting screws, cover and optional heatsink profiles
S
m Mass of a secondary section with heatsink profiles, but without mounting screws, cover and coolant
S,P
168
[1 + α(T - 20 °C)] with the temperature coefficients α = 0.001 1/K for the magnets used.
M,20
(T) = R [1 + α(T - 20 °C)] with the temperature coefficients α = 0.00393 1/K for copper.
STR,20
Definition of the thermal time constant
can be calculated for other temperatures:
M
can be calculated for other temperatures:
STR
Configuration Manual, 10/2018, 6SN1197-0AB86-0BP2
TH
, if the
GRENZ
1FN3 linear motors