Starting Mode: Direct On-Line; Starting Mode: Motor Heating - Siemens SIRIUS 3RW44 System Manual

Device Functions

6.2.5 Starting Mode: Direct On-line

Run-up recognition

6.2.6 Starting Mode: Motor Heating

Typical applications for motor heating
6-10
If the "Direct on-line" starting mode is set, the motor voltage is immediately
increased to line voltage when it receives the start command. This resembles the
starting behavior with a contactor, i.e. the starting current and start torque are
not limited.
Note
Due to the high starting current of the motor, the error "Current limit exceeded"
may occur in direct on-line starting mode. It may be necessary to select a larger
dimensioned soft starter.
The soft starter features an internal run-up recognition. If a completed motor run-
up is recognized, the internal bypass contacts will close and the thyristors are
bridged.
If IP54 motors are used outdoors, condensation occurs in the motor during
cooler periods (e.g. overnight or in the winter). This may lead to leakage currents
or short circuits when the devices are switched on.
A pulsating DC current is fed into the motor winding to warm it up.
If the "Motor heating" starting mode is selected, a heating capacity can be
entered in the settings. This capacity should be chosen in such a way that the
motor will not be damaged. The setting range for the heating capacity extends
from 10 - 100 %. This corresponds to a motor current of approximately 5 - 30 %
of the motor rated current.
Used e.g. in outdoor drives to minimize condensation inside the motor.
Caution
May lead to damage to property.
The motor heating starting mode is not a continuous operating mode. The motor
must be equipped with a temperature sensor (Thermoclick/PTC) to ensure motor
protection. The motor model with integrated electronic motor overload protection
is not suitable for this kind of operation.
SIRIUS 3RW44 System Manual
GWA 4NEB 535 2195-02 DS 04