Siemens SINAMICS G130 Engineering Manual page 376

SINAMICS S120
Engineering Information
Key to formula:
·
R :
BR-min
·
R :
BR-max
The resistance must not drop below the value R
I = 1.5 • I is not exceeded with the response threshold V
max-Brake L-Brake
risk of tripping on overcurrent is avoided. The minimum braking resistance value is specific to the individual unit and
application, and is calculated by the follow formula:
R cold
(
-
BR min
The minimum resistance values R
to the upper response thresholds, i.e. to V
V = 1158 V at line supply voltages of 500 V to 690 V. For other response thresholds, the minimum resistance
DC-max
values R can be calculated as a function of V
BR-min
The resistance must not exceed the value R
P can be achieved with the response threshold V
max-Brake
resistance value is specific to the individual unit and application, and is calculated by the follow formula:
R ( operating
-
BR max
In this formula, the term P
Module, or the maximum total braking power of all three braking resistors, which is required for the specific
application.
In order to guarantee the required braking power and at the same time to maintain a sufficient control margin, the
actual resistance value R
temperature) if possible.
The Braking resistors are not available as standard components in the SINAMICS S120 modular system product
range. They must either be selected from the standard product ranges of suitable manufacturers, or requested from
these manufacturers, e.g. from GINO ESE (www.gino.de), as customized products dimensioned for the required
resistance value and load duty cycle.
Control of the Braking Module
With firmware version 4.3, the Motor Module which functions as a Braking Module must be operated as vector-type
drive object in "V/f control mode with independent voltage setpoint" and at constant frequency (50 Hz). The voltage
setpoint must be generated by means of free function blocks (see Function Manual "Free Function Blocks"), or by
DCCs (see Function Manual "SINAMICS / SIMOTION Description of Standard DCC Blocks"). For this purpose, a
subtractor block is used to compare the current DC link voltage with the freely programmable response threshold. If
the DC link voltage is higher than the response threshold, the inverter enable signal is issued for the Motor Module
functioning as a Braking Module. The difference between the current DC link voltage and the response threshold is
passed through a limiter stage, amplified by a multiplier and finally output as a voltage setpoint to the Motor Module
operating as a Braking Module.
With firmware version 4.4 or higher, the Motor Module which functions as a Braking Module can be operated as
vector-type drive object in V/f control mode "Operation with braking resistor". Parameter p1300 must be set to "15" for
this purpose. The settings of parameters p1360 to p1364 determine the resistance of the braking resistor, the
response threshold and the output voltage. Details are described in function manual "SINAMICS S120 Drive
Functions" and in the List Manual for SINAMICS S120 / S150.
SINAMICS Engineering Manual – November 2015
376/528
Ó Siemens AG
Minimum braking resistance value in the cold state.
Maximum braking resistance value at operating temperature, allowing
for production tolerances of typically about 10 %.
V
R
× =
state
)
BR
I
-
max Brake
are stated in the table of unit-specific technical data. They refer in each case
BR-min
'DC-max
DC-Brake
BR-max
3
× =
temperatur e )
P
max
stands for the maximum total braking power of the MoMo working as a Braking
max-Brake
(operating temperature) should be lower than the calculated value
BR
in order to ensure that the maximum braking current
BR-min
selected in each case, and thus that the
DC-Brake
×
0 7 . V
-
DC Brake
3
= =
I
-
max Brake
= 774 V at line supply voltages of 380 V to 480 V and to
according to the formula shown above.
in order to ensure that the maximum required braking power
selected in each case. The maximum braking
DC-Brake
×
æ
0 7 . V
×
ç
3 DC
×
2
V
è
3
R =
BR
P
- -
Brake max Brake
×
. 0 40415 V
-
DC Brake
.
I
-
max Brake
2
ö
- ÷
Brake
×
2
. 0 49 V
ø
=
DC
P
-
max Brake
BR-max
-
Brake
.
(operating