Functions
7.2 Current limiting function
SIRIUS 3RW50 soft starter
124
Manual, 09/2019, A5E35628455002A/RS-AA/001
Parameter
Parameter
Description
Current limiting value In order to ensure that the drive can reach its rated speed, the minimum
current limiting value that you select must be high enough to generate
sufficient torque in the motor.
A typical value is 3 to 4 times the rated operational current (I
e
).
As soon as the current limiting value is reached, the motor is started with this
value until it has reached its rated operating speed. In this case, the motor
starting times may be longer than the maximum parameterizable ramp up
time.
The maximum possible current limiting value for the 3RW50 soft starter
("max." position) is 7x the value of the maximum rated operational current for
the 3RW50 soft starter, where this value is identical to 7x the value of the
maximum rated operational current I
e
which can be set.
This value is independent of the actual rated operational current I
e
of the
motor set at the 3RW50 soft starter.
•
Factory setting: 4 x I
e
•
Setting range: 1.3 ... 7 x I
e
The setting "max" corresponds to the 7-fold value of the maximum rated
operational current I
e
of the 3RW50 soft starter.
Example
①
Rated operational current I
e
of the motor: I
e motor
= 350 A
②
Current limitation of the 3RW50 soft starter: 4 x I
eMotor
= 4 x 350 A = 1 400 A
③
Maximum current limitation that can be set on this 3RW50 soft starter:
I
max
= 7 x 570 A = 3 990 A
