Derating data

SINAMICS G120P Cabinet units and the associated system components are rated for an ambient temperature of 40 °C and installation altitudes up to 1000 m above sea level.

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

At installation altitudes > 1000 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, on the one hand, to reduce the ambient temperature, and on the other hand, to lower heat loss in the inverter cabinet unit by reducing the output current.

As additional measure for installation altitudes from 2000 m up to 4000 m, an isolating transformer is required in order to reduce transient overvoltages according to EN 60664?1.

Automatic adjustment of pulse frequency

In the factory setting, the drive starts with a pulse frequency of 4 kHz and reduces the pulse frequency automatically to the associated required frequencies when loaded. When the load decreases, the pulse frequency is increased automatically up to 4 kHz. The values of the rated current apply to a pulse frequency of 2 kHz and an ambient temperature of 40 °C and are reached at any time by the automatic adaptation of the output pulse frequency.

Current derating as a function of installation altitude

Permissible output current as a function of the installation altitude for SINAMICS G120P Cabinet units, frame size GX

Permissible output current as a function of the installation altitude for SINAMICS G120P Cabinet units, frame sizes HX and JX

Note:

The connected motors and power elements must be considered separately.

Current derating as a function of ambient temperature

Permissible output current as a function of the ambient temperature

Current derating as a function of the line voltage

The SINAMICS G120P Cabinet inverter cabinet units supply a constant power over the full permissible range of line voltage.

The constant power results in current derating as a function of the line voltage.

Operating ranges

An additional dimensioning aid is available for all inverters with a PM330 Power Module. The purpose of this aid is to ensure the constant reliable operation of the inverter, in particular with regard to service life expectancy.

The dimensioning aid clearly distinguishes between continuous operating ranges and short-time operating ranges. As a result, due consideration can be given to operating ranges when the plant is configured. For further details, please refer to the diagram below and the explanatory text.

Continuous operation (green area) permissible.

Short-time operation (yellow area) permissible for 2 % of the total operating period without significant reduction in the inverter service life; no overload reaction triggered by the thermal monitoring model.

Sporadic short-time operation (red area) permissible for only very short, rare operating states lasting less than 0.1 % of the total operating period without significant reduction in the inverter service life; no overload reaction triggered by the thermal monitoring model on condition of compliance with the duty times specified in the diagram.

Overload capability

SINAMICS G120P Cabinet drive inverter cabinet units are equipped with an overload reserve to deal with breakaway torques, for example. 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.

The unit can operate in two different duty cycles in the permissible continuous operating range shown in the diagram (green area). Depending on how the system is dimensioned, the relevant base-load current is effective as a rated quantity.

The criterion for overload is that the drive is operated with its base-load current before and after the overload occurs on the basis of a duty cycle duration of 300 s.

The base-load current for a low overload I_L is the basis for a duty cycle of 110 % for 60 s or 135 % for 3 s.

The base-load current I_H for a high overload is based on a duty cycle of 150 % for 60 s.

Overload capability, low overload

Overload capability, high overload