Siemens SINAMICS S120 - Rating; Braking Time and Deceleration Distance

Motor components
6.4 Brake resistances (armature short-circuit braking)
Synchronous Motors 1FK7
Configuration Manual, (PFK7S), Edition 12.2006, 6SN1197-0AD16-0BP1
85
Ordering address
Frizlen GmbH & Co. KG
Gottlieb-Daimler-Str. 61, 71711 Murr
Germany
Phone: +49 (0) 7144 / 8100 - 0
Fax: +40 (0) 7144 / 2076 - 30
E-mail:
info@frizlen.com
Internet at:
www.frizlen.com
Note
We cannot accept any liability for the quality and properties/features of third-party products.
6.4.2 Rating
The ratings of the resistors must match the particular I
2
t load capability. The resistor can be
dimensioned so that a surface temperature of 300 °C can occur briefly (max. 500 ms).
In order to prevent the resistor from being destroyed, braking from the rated speed can occur
max. every 2 minutes. Other braking cycles must be specified when ordering the resistors.
The external moment of inertia and the intrinsic motor moment of inertia are decisive when
dimensioning these resistors.
The kinetic energy must be specified when ordering in order to determine the resistor rating.
W = ½ ∙J ∙ ω
2
W [Ws]
J [kgm
2
]
ω [s
-1
]
6.4.3 Braking time and deceleration distance
The braking time is calculated using the following formula:
Braking time:
%
1WRW
%
•9.55
•
=
M
nJ
t
Braking time t
B
[s]
Rated speed n
N
[RPM]
Moment of inertia:
H[WWRW PRW
+= JJJ
Average braking torque M
B
[Nm]
Moment of inertia J [kgm
2
]
Braking distance:
•=
%PD[
stV
2
1
Braking distance s [m]
Velocity V
max
[m/s]