Siemens SIMODRIVE 611A, Installation And Planning Manual

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SIMODRIVE 611 (PJ)
Resistor rating
The resistor ratings can be dimensioned, so that (max. 500 ms), a surface tem-
perature of 300
°
C can briefly occur. In order to prevent the resistor from being
destroyed, the drive may only be braked from rated speed every 2 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.
J
w
1
2
2
W=
W in [Ws]
J in [kgm
2
]
w
in [s
–1
]
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 from the following formula:
J
tot
9.55
t
B
=
1
2
nrated
M
B
J
tot
= J
M
+J
external
s = V
max
t
B
J [kgm
2
]
n
N
[RPM]
M
B
[NM]
t
B
[s]
s [m]
V
max
m
s
[ ]
Braking
time:
Moment of inertia:
Braking travel:
!
Important
When calculating the run–on travel, then for example, the friction (include in M
B
as supplementary factor), the mechanical transmission elements and the
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.
General information on AC servomotors
3 Functions – options