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General Information on AC Servomotors
3 Functions – Options
AL S
ALS/3-34
Resistor rating
The resistor ratings can be dimensioned so that a surface temperature of 300°
C can briefly occur (max. 500 ms). In order to prevent the resistor from being
destroyed, the drive may only be braked from rated speed every two minutes. If
you require other braking cycles, then please specify these when ordering. The
external moment of inertia and the motor moment of inertia are decisive when
dimensioning the resistors.
The kinetic energy must be specified when ordering so that the resistor rating
can be determined.
1
J w
W=
2
W
in
[Ws]
J
in
[kgm
w
–1
in
[s
Braking times and braking travel
In order to calculate the maximum braking times and braking travel, the average
braking torque, the complete moment of inertia and the rated speed must be
known. The braking time is calculated using the following formula:
Braking time:
Moment of inertia:
Braking travel:
Important
!
When calculating the run–on travel, then, for example, the friction (included in
M
as supplementary factor), the mechanical transmission elements and the
B
switching delay times of the contactors must be taken into account. In order to
prevent mechanical damage, mechanical end stops must be provided at the
end of the absolute traversing range of the machine axes.
2
2
]
]
J
<
tot
nrated
t
=
B
9,55
<
M
B
J
= J
+J
tot
M
ext.
1
<t
s =
V
max
B
2
Siemens AG 2000 All rights reserved
SIMODRIVE Planning Guide Motors (PJM) – 11.00 Edition
09.00
2
J [kgm
]
n
[RPM]
N
M
[NM]
B
t
[s]
B
s [m]
m
V
[
]
max
s
6SN1197–0AA20
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