Siemens SINAMICS G130 Engineering Manual page 298

SINAMICS G130
Engineering Information
The flowchart below illustrates the process for doing this.
Flowchart illustrating the process for calculating Braking Module and braking resistor
To reduce the voltage stress on the motor and converter, the response threshold of the braking unit and thus also the
DC link voltage V which is generated during braking can be reduced in operation at low line supply voltages
DC link
within the relevant line supply voltage ranges (380 V to 400 V, 500 V or 660 V). However, this also means a
corresponding decrease in the attainable peak braking power due to P
k = (lower response threshold / upper reponse threshold)
The upper response threshold is set in each case at the factory. The settable response thresholds and corresponding
reduction factors k are shown in the table below.
Line supply voltage
380 V – 480 V 3AC
500 V – 600 V 3AC
660 V – 690 V 3AC
Response thresholds of Braking Modules and corresponding reduction factors k
Example calculation:
The purpose of this calculation is to determine for a SINAMICS G130 converter Chassis unit with an output power
rating of 450 kW at 400 V whether the braking unit with a continuous power rating of P
available for the Power Module is suitable for the application described below. The diagram shows the required
braking power characteristics over time.
Braking power
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Response threshold V
DC link
774 V (k=1) or
967 V (k=1) or
1158 V (k=1) or
~ (V
peak DC link
2
.
with corresponding reduction factor k
673 V (k=0.756)
841 V (k=0.756)
1070 V (k=0.853)
2
) / R with the reduction factor
= 50 kW or P = 200 kW
DB 20