Fluidlexikon

Nominal mode of operation

The nominal mode of operation describes the basic loading of an electrical machine. It is defined in international standard IEC 60034-1. It helps provide an initial assessment of whether a component (motor, hydraulic power pack) is suitable for a particular application.

If no nominal mode of operation is indicated on the machine’s type plate, it is designed for continuous operation with a constant load. The other nominal modes of operation require additional information, such as the switching cycles per hour and the duty cycle.

The following modes of operation are also used for hydraulic power packs:

Code
Description
Development of power (torque) and temperature
S1
Continuous operation with constant load
Load duration is sufficient to achieve thermal equilibrium.
Dauerbetrieb_rechtecke
Dauerbetrieb_Kurve
S2
Short period operation
The thermal equilibrium is not reached during the load period. In the pause between the load cycles, the duration to allow the motor to reach its cold state again is adequate.
kurzzeitbetrieb_rechtecke
kurzzeitbetrieb_Kurve
S3
Periodic intermittent operation
(also: standby mode)
A sequence of identical cycles, each of which contains a constant load and a pause. The starting current is insignificant for heating.
Aussetzbetrieb_rechtecke
Aussetzbetrieb_Kurve
S6
Continuous periodic operation
(also: continuous operation with intermittent load)
Periodic operation with a succession of equivalent cycles, each of which contains a constant load and a no-load time. No pause occurs.
Ununterbrochener_Betrieb_S6_rechtecke
Ununterbrochener_Betrieb_S6_Kurve
Table: Nominal modes of operation for hydraulic power packs