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.

At 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 account that the air pressure, and therefore air density, decreases as the height increases. As a consequence, the cooling efficiency and the insulation capacity of the air also decrease.

Due to the reduced cooling efficiency, it is necessary to both reduce the ambient temperature and 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 currents as a function of the installation altitude and ambient temperature for the various degrees of protection. (The permissible compensation between installation altitude and 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 guaranteed that the cooling air, as specified in the technical specifications, flows through the units as a result of the cabinet arrangement.

As an 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 Motor 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 (1.25 kHz or 2 kHz). 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 specifications.
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 tables list the maximum achievable output frequency as a function of the pulse frequency:

Maximum output frequencies achieved by increasing the pulse frequency in Vector mode

Maximum output frequencies achieved by increasing the pulse frequency in Servo mode

¹⁾ Higher frequencies on request. For further information, see https://support.industry.siemens.com/cs/document/104020669

Derating data for the booksize format

SINAMICS S120 Cabinet Modules with power units in 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 in 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 factors 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 in the configuration. For 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.

Another precondition is that the Motor Modules are operated at their factory-set pulse frequency at output frequencies >10 Hz.

For temporary, periodic duty cycles with high variations of load within the duty cycle, the relevant sections of the SINAMICS Low Voltage Engineering Manual must be observed.

Motor Modules in chassis format

Motor Modules with power units in 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 I_H for a high overload is based on a duty cycle of 150 % for 60 s or 160 % for 10 s.

High overload

Motor Modules in booksize format

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

High overload

Line Modules in 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.