Braking Resistors For Power Units In Chassis Format - Siemens SINAMICS G130 Engineering Manual

SINAMICS S120
Engineering Information
Braking Modules can be ordered separately as SINAMICS S120 system components or as an option in the
SINAMICS S120 Cabinet Modules product range (options L61, L62 or L64, L65). When ordered as an S120 Cabinet
Modules option, the Braking Modules are shipped as pre-installed and pre-wired components.
If Braking Modules are ordered as SINAMICS S120 system components, the matching braking resistors must be
ordered separately. When options L61, L62 or L64, L65 are selected from the S120 Cabinet Modules product
spectrum, the order automatically includes the matching braking resistors for the relevant Braking Modules.
6.8.2

Braking resistors for power units in Chassis format

Braking resistors convert excess DC link energy into heat. The braking resistor is connected to a Braking Module. By
positioning the braking resistor outside the cabinet or outside the switchgear room, it is possible to dissipate the heat
losses at a far distance from the cabinets or switchgear room, thereby reducing the level of air conditioning required.
Braking resistor in degree of protection IP20 for connection to a Braking Module
Resistors with continuous power ratings of 25 kW and 50 kW are available to match the ratings and load duty cycles
of the Braking Modules designed for mounting in air-cooled units in Chassis format. Higher power ratings can be
achieved by connecting Braking Modules and matching braking resistors in parallel.
The braking resistor temperature is monitored electronically by the Braking Module to which it is connected. The
resistor is also equipped with a temperature switch (NC contact) which responds when the permissible limit
temperature is exceeded. The floating contact of the temperature switch can be evaluated by the converter or a
higher-level control.
Installation
The braking resistors are only suitable for vertical installation and not for installation on a wall. During operation
surface temperatures can exceed 80ºC. In view of this, sufficient distance from flammable objects must be
maintained. A free-standing braking resistor installation with at least 200 mm of free space on each side for
ventilation is required. Objects must not be deposited on or above the braking resistor. The installation should not be
carried out near fire detectors as they could respone by the produced heat. It has also to be ensured that the place of
installation is able to dissipate the energy produced by the braking resistor.
The connection cables to the Braking Module must not exceed 100 m. A short circuit-proof and ground fault-proof
cable routing must also be provided.
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Ó Siemens AG