Siemens SINAMICS S120 - Page 370

SINAMICS S120
Engineering Information
SINAMICS Engineering Manual – November 2015
Ó Siemens AG
370/528
Braking Module
+ 24 V
Fault output
0 V
Inhibit input
0 V
X21
21.6
21.5
21.4
21.3
21.2
21.1
Inhibit
Fault
Connection to the
DC link
DCPA
DCNA
J
D
Braking resistor
T1
T2
R1
R2
Connection of Braking Module and braking resistor with SINAMICS S120 Chassis
The diagram below illustrates the power definitions and specifies the permissible load duty cycles for the Braking
Modules and matching braking resistors. The information is valid for the factory-set response thresholds.
Power definitions and load duty cycles for Braking Modules and braking resistors
How to determine which Braking Modules and braking resistors are required
The process for calculating the continuous power rating of Braking Modules and braking resistors required for a
particular application is explained below.
1. Calculating the mean braking power P
mean
First of all, the mean braking power P
mean
needs to be calculated on the basis of the specified load duty cycle.
· For periodic load duty cycles with a duration of T ≤ 90 s, it is necessary to determine the mean braking power
P
mean
over the whole load duty cycle duration T.
· For periodic load duty cycles with a duration of T > 90 s or for sporadic braking operations, it is necessary to
determine the mean braking power P
mean
over the time interval during which the maximum mean value occurs. A
period of 90 s must be applied as the time base for calculating the mean value.