Braking Resistors; Description - Siemens SINAMICS S120 Manual

DC link components

5.2 Braking resistors

5.2 Braking resistors
5.2.1

Description

The excess energy of the DC link is dissipated via the braking resistor.
The braking resistor is connected to a Braking Module. The braking resistor is positioned
outside the cabinet unit or switchgear room. This enables the resulting heat loss around the
Basic Line Modules, Smart Line Modules, Active Line Modules, or Motor Modules to be
dissipated. This reduces the level of air conditioning required.
Resistors with rated powers of 25 kW and 50 kW are available.
Greater outputs can be implemented by connecting Braking Modules and braking resistors in
parallel. In this case, the Braking Modules are installed in the air duct of the Line Modules
and Motor Modules. Depending on the size of the respective module, up to three mounting
locations are available.
Since the braking resistors can be used in converters with a wide voltage range, the voltage
can be adjusted (for example, to reduce the voltage stress on the motor and converter) by
setting the response thresholds on the Braking Module.
A thermostatic switch monitors the braking resistor for overtemperature and issues a signal
on a floating contact if the limit value is exceeded.
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Manual, (GH3), 01/2013, 6SL3097-4AE00-0BP3
Chassis power units