Derating data for the chassis format

SINAMICS S120 Cabinet Modules and the associated system components are rated for an ambient temperature of 40 °C and installation altitudes up to 2000 m above sea level.

For ambient temperatures > 40 °C the output current must be reduced. Ambient temperatures above 50 °C are not permissible.

At installation altitudes > 2000 m above sea level, it must be taken into consideration that with increasing height, the air pressure decreases and therefore the air density. As a consequence, the cooling efficiency and the insulation capacity of the air also decrease.

Due to the reduced cooling efficiency, it is necessary, on one hand, to reduce the ambient temperature and on the other hand, to lower heat loss in the Cabinet Module by reducing the output current, whereby ambient temperatures lower than 40 °C may be offset to compensate.

The following table specifies the permissible output current as a function of the installation altitude and ambient temperature for the various degrees of protection (the permissible compensation between installation altitude and the ambient temperatures < 40 °C – air intake temperature at the entry to the Cabinet Module – has been taken into account in the specified values).

The values apply under the precondition that it is a guaranteed that the cooling air, as specified in the technical data, flows through the units as a result of the cabinet arrangement.

As additional measure for installation altitudes from 2000 m up to 5000 m, an isolating transformer is required in order to reduce transient overvoltages according to EN 60664-1.
For additional information, please refer to the SINAMICS Low Voltage Engineering Manual.

Current-derating factors for Cabinet Modules as a function of the ambient/air intake temperature, the installation altitude and the degree of protection.

Current derating for SINAMICS S120 Motors Modules, chassis format as a function of the pulse frequency

To reduce motor noise or to increase output frequency, the pulse frequency can be increased relative to the factory setting. When the pulse frequency is increased, the derating factor of the output current must be taken into account. This derating factor must be applied to the currents specified in the technical data.
For additional information, please refer to the SINAMICS Low Voltage Engineering Manual.

Derating factor of the output current as a function of the pulse frequency for units with a rated pulse frequency of 2 kHz

Derating factor of the output current as a function of the pulse frequency for units with a rated pulse frequency of 1.25 kHz

The following table lists the maximum achievable output frequency as a function of the pulse frequency:

Derating data for the booksize format

SINAMICS S120 Cabinet Modules with power units, booksize format and the associated system components are rated for an ambient temperature of 40 °C and installation altitudes up to 1000 m above sea level. If SINAMICS S120 Cabinet Modules with power units, booksize format are operated at ambient temperatures higher than 40 °C and/or installation altitudes higher than 1000 m above sea level, then the corresponding derating functions must be taken into account as a function of the ambient temperature and/or the installation altitude. These derating factors are different from the derating factors for the chassis format power units and are listed in Catalog PM 21.

Overload capability

SINAMICS S120 Cabinet Modules have an overload reserve e.g. to handle breakaway torques. If larger surge loads occur, this must be taken into account when configuring. In drives with overload requirements, the appropriate base load current must, therefore, be used as a basis for the required load.

Permissible overload assumes that the drive converter is operated at its base load current before and after the overload occurs, based on a duty cycle duration of 300 s.

For short, repeating load cycles with significant load fluctuations within the load cycle, the appropriate sections in the SINAMICS Low Voltage Engineering Manual must be observed (as PDF file on the CD-ROM provided with the catalog).

Motor Modules chassis format

Motor Modules with power units in the chassis format can be configured on the basis of different base load currents.

The base load current for a low overload I_L is the basis for a duty cycle of 110 % for 60 s or 150 % for 10 s.

Low overload

The base load current for a high overload I_His the basis for a duty cycle of 150 % for 60 s or 160 % for 10 s.

High overload

Motor Modules booksize format

Motor Modules with power units in the booksize format have the following overload capabilities:

High overload

Line Modules chassis format

The base load current for a high overload I_H DC is the basis for a duty cycle of 150 % for 60 s or I_max DC for 5 s.