Changing The Power Block On Air-Cooled Power Units In Chassis Format - Siemens SINAMICS G130 Engineering Manual

General Engineering Information for SINAMICS
Engineering Information
Setting the temperature of the air conditioner
It is strongly recommended that the setpoint temperature of the air conditioner is not set too low. Very low settings for
the internal temperature of the cabinet can lead to excessive wear on the cooling unit, extremely high condensate
formation, unnecesarily high power consumption and high levels of relative air humidity with the risk of condensation
that can potentially result in the failure of the drive equipment inside the cabinet.
Furthermore, when there is a very large difference between the temperature inside the cabinet and the ambient
temperature outside the cabinet, there is a risk that condensation will form when the cabinet doors are opened.
For these reasons, the setpoint temperature of the air conditioner must be set according to the maximum predicted
relative air humidity at the installation location and the setting must not be too low. With a relative air humidity of up to
60 %, the temperature should be set approximately 10°C lower than the permissible ambient temperature of the built-
in units. With a relative air humidity of up to 90 %, the setpoint temperature should be only approximately 5°C lower.
Furthermore, the switching hysteresis on air conditioners with two-step controllers should be only a few °C. With a
permissible ambient temperature of 40°C for SINAMICS built-in units (without current derating), it is therefore
advisable to set the air conditioner to approximately 30°C. The switching hysteresis should equal ≤ 3°C if possible.
Use of climate control systems
The same principles apply analogously to systems used to control the climate of rooms in which SINAMICS cabinet
units are installed. To prevent the risk of condensation, the room temperature setting should not be too low and the
outlet openings of the climate control system should not guide cold, moist air directly into the air inlets of the cabinet
units, but should be arranged such that the cold, moist air expelled by the climate control system has the opportunity
to mix with the slightly warmer, dry room air before it can enter the air inlets of the cabinet units. The same
information given above regarding air conditioners also generally applies with respect to the setpoint temperature of
the air conditioner as a function of relative air humidity and to the switching hysteresis of the two-step controller.

3.7 Changing the power block on air-cooled power units in Chassis format

An installation fixture which is a helpful tool for replacing the power blocks in air-cooled Chassis units and air-cooled
cabinet units is available as an option. It is designed to simplify mounting and dismounting of the power blocks.
Installation fixture for the power blocks of air-cooled SINAMICS units in Chassis format
The installation fixture is placed in front of the power block to be replaced and fixed to the frame of the power unit.
The telescopic rails on the fixture allow it to be adjusted to the mounting height of the relevant block. After the
mechanical and electrical connections on the power block have been detached, it can be withdrawn from the power
unit. As it is removed, the power block is guided and supported by the guide rails on the installation fixture. The block
can then be lifted off the fixture.
SINAMICS Engineering Manual – November 2015
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Ó Siemens AG