Capacitors For Improving The Power Factor - Siemens 3RW44 Manual

Note
There are two possibilities of protecting against a short-circuit:
Protecting against short-circuits in accordance with type of coordination 1:
the device may be defective after a short-circuit and must be replaced. Chapter Feeder
component layout (standard circuit) (Page 270) contains details of fuses/circuit breakers for
short-circuit protection in accordance with type of coordination 1.
Protecting against short-circuits in accordance with type of coordination 2:
the device is not damaged by a short-circuit. Type of coordination 2 is recommended for high
plant availability. The soft starter has internal protection to prevent overloading of the
thyristors during normal operation. This internal thyristor protection function is not sufficient,
however, in the event of a defect in the motor windings or a short-circuit in the motor's power
supply cable, for example. Special semiconductor fuses, e.g. SITOR fuses from SIEMENS,
must be used for this purpose.
NOTICE
Risk of property damage
Type of coordination 1 in accordance with IEC 60947-4-1: The device is defective following
a short-circuit failure and therefore unsuitable for further use (personnel and equipment
must not be put at risk). Type of coordination 2 in accordance with IEC 60947-4-1: The
device is suitable for further use following a short-circuit failure (personnel and equipment
must not be put at risk). The type of coordination only refers to soft starters in conjunction
with the stipulated protective device (motor starter protector/fuse), not to additional
components in the feeder.
4.4

Capacitors for improving the power factor

NOTICE
Capacitors must not be connected to the output terminals of the soft starter. If so, the soft
starter will be damaged.
Active filters, e.g. for power factor correction, must not be operated parallel to the motor
control device.
If capacitors are to be used to correct the power factor, they must be connected on the
device's line side. If a contactor disconnector or main contactor are used together with the
electronic soft starter, the capacitors must be disconnected from the soft starter when the
contactor is open.
3RW44 soft starters
Manual, 03/2017, NEB535219502000/RS-AB/008
Installation, connection and feeder configuration
4.4 Capacitors for improving the power factor
41